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I am currently renovating my new first home and I need to do this to my entire house (external solid walls) Just wondering, did you need to get Building regulations approval to do this ? I'm a little confused where I stand with this. I have to do attic, walls and insulate under the raised floor.
I wonder if you have secured/ painted external walls. To be honest, I wouldn't go for that internal installation. Better would be external for longer run.
I built a two storey extension as a granny annex in 2003 using 40mm laminate plasterboard dob and dabbed onto 9" solid block work. I recently put new doors and windows in and uncovered a lot of the original wall surface. Not a hint of mould or condensation. External walls are rendered pebbledash. I am now doing the same to the main house external walls as i replace the old leaded light windows. If you try and consider all the issues you come to the conclusion its not worth it bearing in mind the cost and no one can get give a definite way to do it. however I need to be warmer as i get older in the winter. This time I am using adhesive foam which almost removes any gap behind the insulation as it needs perfect contact (keep pressure applied for half-hour plus across the whole board with temporary wood support and of course mechanical fixings). We do intend to open windows as much as possible to reduce humidity issues. in 10 years time I'll let you know if it worked!
Interesting video Charlie. Not to be only pointing out issues but I see two potential problems with this arrangement. Firstly there are many unventilated cavity spaces right where the dewpoint position is (internal face of the brickwork wall), surely that is perfect conditions for mould. Secondly, with the batten fixed directly to the brickwall they will act as cold bridges, a studded frame build independently say 20mm off the brickwork would have avoid the cold bridge, or even a "warm" batten with 25mm insulation fixed behind the batten. Regardless an interesting subject where it is near impossible to satisfy all requiments!
Positive ventilation unit pushing air into the cavity space if its a continuous maze gap with trickle vent exits? would that cause any issues with the inner shell?
Eager to see how you achieve this. I am going through a renovation myself and we have decided against internal wall insulation due to several factors. and will therefore try to attempt external insulation in the future. I spent ages reading about how to insulate, and even airtightness, and too many approaches out there to say the least. It was too confusing and tradespeople did not help.
What's important to me from this video is you have taken the time to really think about the insulation - which I find hard to do with work consuming my life. Thank you for the research
Woodfibre insulation fully bonded to the wall with lime plaster over or Diathonite insulated plaster would have been the best option. Standard best practice is to not leave a cavity next to the wall as you will get mould growth just like you did before. It is almost impossible to prevent air ingress into that cavity. You also need to remember to insulate between the joists in the inter floor void next to the wall having parge coated first around the joists to prevent air ingress.
Hmm, yet perhaps to reduce service penetrations you could perform your insulation then have a horizontally battened service cavity with airtightness layer behind traditional plasterboard. This means religiously taping that barrier behind each socket box and penetration before mounting the plasterboard.
Better still simply tape the airtight barrier to the Lime insulation, then attach the electrics taking care to seal around the screws. The same dedication would have to be taken for the screws mounting the plasterboard battens. Then attach the boards..
I would use Steico's system of applying wood fiber board to a masonry surface and then finish with either a vapor permeable wallboard or a lime plaster which is also vapor permeable. I would then finish with a vapor permeable paint. You are relying on a cold air cavity to control moisture which will over time probably fail. You are also not allowing the walls to dry out causing them to deteriorate over time. The walls were made to breathe, you have to let them.
Charlie says its a '2 brick course with no cavity' - we dont know if its a lime mortar pointing(but he seems to allude to that with the proposed lime insulation solution eval). If he currently has a "mix and match" lime and cement mortar pointing(which is typically of older houses with a mix of more recent renovations). IMO Even with a lime internal plaster composite integrated insulation layer(no gap) it may not resolve the damp penetration patches and cold spots due to any prior use of cement.. Charlie's solution, basically a fancy raised dry wall inner shell concept, typically has a ~30 year life before batons and plaster/insulation degrade and damp/mould penetrates, certainly should provide a better U-Rating, terminal conductivity is limited to the wooden batons and that seems to be his No1 concern. Future concern is the stone and mortar health behind the shell (degraded lime due to lack of breathability) and mould builds up on the inner wall surface. Unless you incorporate some air pocket ventilation between the gap of outer shell and inner solid wall to wick away the moisture and control/reduce mould growth, such a wall gap ventilation system would also also help preserve the wood batons extending the life of his solution, help preserve any stone & lime mortar with his walls. Technically it would be interesting to know the temp difference between that inner shell (outer surface) and the inner wall surface and also the humidity of the air gap over time to identify and help ID level of mould and moisture damage.
if you screw your 38mm batons horizontally making a grid pattern you will limit the cold bridge. you could also insulate between the batons. Don't forget you need a ventilation system (ideally a heat recovery system) to deal with all the vapor that can now not pass through the walls. A healthy house requires heat and ventilation working in conjunction. The tighter you make a house the more important this becomes.
Agreed! Nothing will cause more issues that a house that can’t “breathe” it will cause voids to sweat etc and thats almost as bad as having a leak you don’t know about
@@therabman_5606would open trickle vents on all windows be sufficient? I’m just about to start insulating our bedrooms and don’t want to create another issue
@@peterreime3146 you put plastic on the vertical battens and then the horizon battens, you can run the electrics in between the plastic and the horizontal battens, there is enough give. You have to use soft insulation for this kind of solution or if hard insulation must be used then it must be thinner than the vertical battens. The upside to this is that you don't have any penetrations in the plastic. But there may be places where it is appropriate to cut or drill the top batten. One can also put an extra 22mm vertical batten to create space for electrics. There are many solutions to stop cold bridges and have an airtight seal.
Which is better during winter cold in a more air tight reno: ventilation (ie trickle vents) or smart dehumidifier or mix of both? retain the heat, lose the water.
I would have dabbed 50mm PIR to the walls and foil taped the joints, then mechanically fix the boards to the wall with plastic 10mm board fixers. That way you’ll get the walls nice and straight. Next, I’d have fixed the plasterboard to the surface of the PIR with expanding foam adhesive. Soudal do a great glue and very easy to use. I never buy insulated plasterboard as it’s twice the price. Battening a wall creates a cold bridge.
There are a number of internal wall insulation options that are breathable which is the best option as you get you u-value. These include but not limited to wood fiber insulation and lime render with cork or pumus stone in it put on at about 50m thick. (A friend did the latter on his listed cottage and it's amazingly warm)
@@inh415 breathability and air-tightness are two different things. Materials like wood fibre can help to prevent moisture buildup in walls by absorbing any condensation at the cold surface (assuming good contact with a breathable adhesive like a lime mix). The moisture can then be wicked back through the insulation, and when the internal humidity drops breath out into the room again. Air tightness on the other hand prevents penetration of air from outside. Wood fibre insulation, whilst not completely air tight, does obstruct airflow, and you can get vapour-open air-tight materials, both as membranes and as paint-on treatments. And intelligent valour membranes can be used to prevent/reduce vapour penetration into the wall from the room, whilst still allowing vapour to breath out into the room (usually at a certain relative humidity and temperature range).
@@DevAnubis Yep, i'm looking at this option as well, wood fibre boards from STEICO. It fits in with the "design philosphy" (if you can call it that) of an old solid brick walled house. Back in the day they didnt have the means to stop moisture at any point (sandstone block foundation) and just let it come and go. And they ran direct wood-fired stoves which kill moisture so fast you wish you had more lol. Covering up these walls from any side with anything that stops water is asking for trouble. The wood fibre board solution sounds almost too good to be true as the installation looks fairly simple and doesnt require several layers of whatnot.
Hi Charlie, you say using lime plaster wouldn't be warm, however I see other breathable materials on the market like Diathonite Thermactive, which is lime based plaster but has a thermal conductivity of 0.037 W/mK, which although performs only half-decent when compared to something like Kingspan option, but it wouldn't require the void, meaning actually you could add a thicker layer, which then starts matching the Kingspan! On top of that I see that other options like Wood Fibre or simple sheep wool also have thermal conductivity of ~0.038 W/mK, which likely would make this a simpler project and cheaper. I haven't calculated the difference in cost, but I dare to say it would make it a lot less complex and potentially less risky? What is you opinion on this?
@@montvydasklumbys7584 Now try to heat up it after insulted from inside. As soon as heating is off it cools instantly down. Air alone doesn't hold much heat.
I will be doing this very shortly in my two front rooms. I have decided use PIR straight onto the brick wall, batten a frame in front of it and screw battens to ceiling and floor joists. This way there is no compromise in the insulation. Socks can go in the void behind the stud wall.
Interested in the route you go down, I'm about to undertake this, by using 3x2 CLS stud work to the wall, filled with wood fibre, vapour barrier taped over followed by butyl tape along the studs and noggins so when the plasterboard is attached the barrier isn't compromised. My reason for this route is so that I have good fixings for shelves, radiators etc. It also allows me to get the wall level and plumb which is currently is not
Nice video, refreshing to see some common sense regarding the lime plaster. It's a nice idea but like you, the end of my house is solid brick wall and without my wood burner I'd be screwed as it gets really cold and if you can make it warmer then go for it. Interestingly I got damp problems in this part of my house after painting the outside of the house using sandtex paint. I think it stopped moisture escaping outwards, maybe a video opportunity for the future! But I think your option looks good. Unfortunately as you say, many manufacturers fail to include how to deal with sockets, ducts etc and it ultimately comes down to you to come with the best solution. Best of luck with it 👍
Thanks buddy. Sorry to hear about those problems. I've found the Emperor fantastic ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-zw_8YVFKY1M.html Problem with most exterior paints is they're only water RESISTANT and aren't breathable unlike this stuff. They also do a translucent cream for applying to brickwork you don't want to paint. 👊
For sockets there is an airtightness product that is a rubber gasket with a small hole in it to poke the cable through. I am goint to stick insulated boards directly to wall with adhesive foam with a continuous bead all the away around the edge. The rubber gasket will be stuck to back of the board where the cables will poke through. Then I may use shallow surface mounted boxes or use shallow depth boxes. If the latter I will remove plaster board and some insulation. Then line the cavity with foil tape to renew the vapour barrier. Where the boards but against each other I will use a bead of sealant, something like pro clima, to make the vapour barrier continouus at these junctions. Then foil taping over the the joints before jointing compound or plaster. At ceiling and floor I will use the foam adhesive to make up any large gaps then paintable sealant on top and possible foil tape to floor at ground which will be hidden by skirting and floor covering. Also using same sealant where the boards butt up against window frame. This the best I can come up with as a timber frame would loose me too much room space. Solid brick wall, built around 1911, recently rendered outside with sand and cement and inside with gypsum plaster. To use any of the breathable internal solutions most advise removing all cement or gypsum from the wall inside and out and I just can't bring myself to do it and EWI is eye wateringly expensive. 🤞all constructive thoughts welcome
Amazing to find a builder who actually does understand and considers how to refurb properly and follows or improves on building regs. If only every builder did this.
How much better insulation do you get from a PIR with a lambda value of 0.0022 compared to the standard 0.0037 ? In my country outer walls are getting up 700mm thick on new houses because we need more and more insulation to live up the minimum requirements. I wish there were somewhere you could compare how much more insulation it would take to get the same U value
@@otofoto Correct and that is the problem in my view. The house becomes very expensive and not much space inside compared to outside. That is why insulation like PIR is potentially interesting. If it is possible to get the house approved for thinner walls then it becomes a better option
@@jwester7009 Better look at silica gel insulation. It is inorganic and non-toxic. Unfortunately none of insulation for older buildings is economically viable. It never pays off and after 10years there are new codes and again need to change everything. None of such investments are paid off, pointless.
As you will will know Charlie internal insulation on a old wall is a risky business and there is no 100% solution to it I feel in my experience counter battern it so that there is an airflow across the wall but you will have to vent it possibly from the outside somehow also use stainless steel screws in wall when battening
I have solid walls. I'll be fitting internal wood fibre insulation to my outside facing walls. Then applying a lime plaster. Hopefully that will keep the room warm, breathable and dry. My house is having a few mould issues due to external cement render and internal gypsum plaster. I'll be removing the render over easter and chipping away room by room with IWI and lime plaster.
Hi Jay, interested in this because I'd like to do similar. Have you chosen specific products yet? It's seems very hard to find options that aren't gypsum!
@Juliette Bauccio I have yes. I will be going for the steico wood fibre insulation, 30mm for my first project then hopefully go thicker in places where I can.
@a silver oh yes, I found his videos soon after I moved into my victorian home. I honestly didn't realise how much cement and gypsum damages soft red bricks. I will be repointing all the bricks in new lime morta. I am actually going to make my own lime putty soon as its quite expensive.
Fascinating topic. I'm not sure if I'd be willing to lose c.140mm of space internally - that's a lot of volume when you think about how big your external wall is. That said, your idea does seem very comprehensive at addressing the issue of heat loss
It's really only on the one wall in the kitchen so once it was up we won't notice. More of an issue is in the other part of the room where we have a doorway that is already narrow. ..
When I’ve insulated solid brick walls, I’ve used 50 mm celotex/kingsman straight against the wall, fit the insulation to the walls through 38mm battens, set out to suit the plasterboard, and the 12mm plasterboard to the battens. You can now run cables in the void, cut out drying holes to plasterboard, without damaging the insulation, which is all kept intact & sealed.
Good stuff. Having looked into internal insulation it's clear that it's a murky area with unclear best practices. Props for trying to tackle the issue and bring clarity on different options
Agreed - I've been upgrading my home, which has a cavity wall that the previous owners insulated at some point. Trying to get any consistent information on how to boost the insulation is nigh impossible. I went with a dot-dab insulation approach like I saw on this channel before and it has been extremely effective for me in one room, now considering whether to do likewise in other rooms, it looks like there might be ways to up the game.
@Alex Barlow dot and dab is fine for most walls as long as there is no shelving or units built there like a kitchen etc. It becomes a pain in the backside though if you decide to start putting up shelves or units after. If its like 50mm insulation or higher. We went with battoning the walls like Charlie here and used two 2x2 stacked on top of each other which allowed us to fit 80mm insulation in between it with a few mm gap for air. We're very happy with it and it's very warm now, even during the last winter. But we also upgraded all the windows to triple glazed from Poland as well. Definitely recommend but either way, insulating is such a great investment. We insulated the whole lot for about £6000 and got the windows for £3500. All the work done ourselves.
Yes I'll definitely get rid of the mould Fred. I'll probably spray it with a bleach solution or something like Zinsser Mould Remover, assuming I don't hack off the render entirely.
Fix the studs top and bottom so you have no bridging back to the wall. 10mm gap for insulation is good, allows the foil to reflect infrared back. Try and stay away from PIR these days because of the poor fire performance but appreciate it's better thermally. Take a look into rockwool and a separate VCL like visqueen which you can staple to the face of the studs and cut down the joints. You also wouldn't need the gap for cables with this as its more flexible which might help offset the performance difference. FYI you can get thermally broken insulation fixings to reduce the bridging.
Hey Charlie, I haven't watched it all but there are a lot of options to insulate with lime whilst still maintaining a vapour open construction. There are cork insulated plasters which can give a good u value, also wood fibre with lime plaster would be vapour open too.
This is a far better option IMO. Insulating breathable lime render directly onto the masonry. Vapor barriers and whatnot to keep internal moisture out of the space between the plasterboard and the masonry are never going to be truly airtight and therefore moisture in the air WILL find its way behind at some point.
Suppose all well and good if you have the available space to shrink the room by net 120mm per external wall after hacking off the old lime plaster (in my case). My kitchen is 2200mm wide so just not a realistic solution. Chucking up external insulation over period features on a victorian property....the net zero lot can chuff off!
Interesting approach, look forward to seeing how it works out. Fingers crossed it works like you want it to. I came across a relatively new product that's an insulated wet plaster/render which can be used internally called proof therm by a company called proof shield. It's a traditional wet plaster with insulating materials mixed in. Showing some quite interesting u-values.
@@roscopeco2000 I just calculated, 220m brick would require an internal plaster layer at 160mm thick for that product to fall within building regs for existing fabric of U value 0.3 - not feasible really
Emissivity refers to an object's ability to emit thermal radiation, which can impact the appearance of its temperature in thermal images. Different materials have different emissivities, meaning they emit thermal radiation differently. For example, a shiny metal surface with low emissivity might appear cooler in a thermal image than a piece of wood with high emissivity, even if they are actually the same temperature. This is because the metal reflects more of the surrounding thermal radiation, while the wood emits more of its own heat.
Indeed. I have a thermal camera and can show drastic changes between materials. Also the cold spots in the corner of a room are pretty common. It’s the coldest point where the airflow is least. I would expect behind a sofa to be cold too.
Great video Charlie. There’s an interesting EU project called Ri Build. It’s essentially research being done into the best approaches for internally insulating historical buildings. They have a calc that helps determine the recommended maximum amount of insulation for a given type as too much can introduce potential issues with timber rotting and cracks forming due to frost.
Thanks buddy - that's really interesting. I'm actually going to go with a breathable system now from SWIP. There'll be a video on this later in the year. 👊
@@CharlieDIYteHi Charlie. Any progress with SWIP and your video? How was your experience? I'm looking at their products currently but need to find a local, accredited installer first.
Great video Charlie, I've been getting involved in external and some internal insulation, I have solid walls and have researched this complicated subject, I have used alutrix vapour barrier and a combination of foam fixing and insulated plasterboard. you can end up chasing cold bridges until the cows come home . Somewhere the vapour barrier has to be breached. As you rightly say, ventilation is essential as moisture will build up eventually. Interestingly I ripped down 4mm conti board pinned to batten on my dining room walls and found the external walls bone dry. Unluckily my lead roof laid 20 years ago on a warm roof where no barrier was installed erupted and dissolved to white dust. You live and learn.
I'm of the opinion that voids will always have some amount of air 'leakage' into them no matter how much foil tape and we'll made the walls are. And then you've got damp air trapped in a void with a cold wall for the moisture to condense on and with very little way for it to evaporate (after all, you've just spent lots of time foil taping it etc to try keep it out in the first place). Which is gonna lead to mold growth on the wall. It's a similar debate that the Diy campervan community has, spray foam vs wool, with a void between the insulation and the vans body skin to let it breath? Or let the insulation touch it and risk having it rust. I honestly can't think of a good solution and I've been thinking about this for 2 years now. Good luck I look forward to am update
The difference between a camper van and a solid wall though is when moisture condenses on a solid wall it will be wicked out towards the outside of the house where it will evaporate, that’s how old houses were designed to work, assisted by well breathing lime mortars. Until someone cement renders the wall, restricting the escape route for the moisture.
Internal wall insulation in cold climates (eg UK) is a bad idea full stop. Your building will rot. I know - I've done lots of it. Will only use external insulation in future. It only works if: 1) You fully seal the inside with a perfect vapour barrier, which is almost impossible in an old building. What do you do about joist ends? And in the space between floors? 2) You have a breathable cavity between your insulation and the original wall. With holes drilled to the outside. 3) You strictly control the humidity inside the house by installing a whole house MVHR system. 4) You make sure you don't insulate too well! There needs to be some heat lost through the external walls to drive the moisture out. If you do all this it will work and be fine. But it's rare to find tradesmen who will tape every single pinhole, unfortunately over time MVHR systems won't be maintained, roofs will leak into your cavities, and because you've insulated and sealed on the inside, you WON'T BE ABLE TO SEE THE LEAK until it's rotted your whole wall.
As Charlie said, he won't get enough insulation with that method. There is a good reason that you can't buy insulated lime -hemp plaster from builders merchants. It is a niche product and won't meet building regs.
Interesting video as I’m currently looking into this for my own house. I have used a product called superquilt in the past on other building projects, and it’s very effective. Not only does it provide a lay of insulation it is also a vapour barrier. You just have to make sure you tape the perimeter and overlap with silver tape. You simply batten your walls and counter batten over the top. Seems to be the best product to stop any cold bridging. I thought I’d share this with you
Thanks Craig, that's interesting. I have a wall on the south side that can't be insulated with anything too thick due to a doorway that's already tight so I'll put that into the mix 👊
VERY GOOD CHARLIE YOU IDENTIFY ISSUES & THEN RESOLVE THEM YOUR BEST BET IS YOURSELF I THINK YOU ARE A PROBLEM SOLVER, DISREGARD ALL ARMCHAIR GENERALS. REGARDS TOM😊
Have you ever heard of Gypliner ? Or its generic equivalent. It's been around for at least 30 years. Granted I just flicked through your video but I'm puzzled by your fascination with timber in these circumstances. If you are attaching timbers to such a wall what is your method of keeping the wall plum and straight in a time/motion efficient manner ?
Second this. Gypliner type system or a gypliner independent wall lining system would be a much more modern solution. Negates any issues with cold and damp bridging and not much difference in cost compared to timber battens. No shrinkage either so might negate need for the Gappo tape. Could consider installing weep vents in the cavity void for airflow.
Love the video and detail! I am in the process of applying IWI on the front external wall of a Victorian terrace. I striped back to the brick work, some which showed clear signs of spalling; not surprising given the air gap caused by Dip and Dab gypsum plasterboarding over the original Lime plaster (creating a cavity where moisture could not escape). I have applied around 30mm of Diaphonite Thermactive, then fixed 60mm Uditherm Woodfibre board on that with insulated screw fixings and using the a wet layer of Diaphonite as lime adhesive. Not sure about the results yet but interested in next winter to perform analysis to the temperature, humidity and thermal imaging (not to mention out gas bill!). Just another thing, it was pointed out to me by a builder who works at CAT that there are common misconceptions about interstitial condensation (dew point moisture) and general moisture caused by cooking, cleaning etc. As I understand it, the latter has very little to do with mould growth within the wall structure. Interstitial condensation just requires some cavity where moisture will condense from any air which pretty much always has a certain amount of moisture in it. With that in mind, a safer approach is to simply allow the moisture to escape. Lime is also alkaline and anti microbial. If anyone is interested in Diaphonite or other insulating Lime plasters, I would recommend contacting Carrington Lime in Gloucestershire who run practical and online courses/seminars on the specific products.
I don't know if I was overkill or not, but I built a stud wall 50mm from a granite wall with 100mm deep timber. I then put Kingspan pir 100mm with gapo tape. Where the sockets are I put two noggins directly above and below the box, and a bit of ply out the back and expanding foam to fill. Then I put a green vapour barrier up, and plaster board ontop, and got a plasterer in. I then used a vinyl mat paint as I hope it will block vapour also, but for me the 50mm out the back provides a ton of ventilation from the attic. Let me know if anyone can see anything wrong with the setup as I have all the other bedrooms to do this summer!
If cost was not an issue, something like aerogel backed onto a magnesium oxide board would be ideal. It’s breathable extremely efficient and thin. But very expensive.
In our solid walled home I sealed round the edges of whole sheets of foil backed PIR (celotex etc) with silicone and put that directly onto the plastered wall. Then fix 50x25 tile battens over this to mechanically fix the boards to the wall foil tape the joints then fix the plasterboard to the battens. Gives a nice 25mm warm void behind the plasterboard for the sockets etc with no interruption to the vapour barrier. The whole wall is completely covered with insulation no battens in the way. Also no chance of the battens rotting as all on the warm side of the insulation. Would say the walls are almost air tight in theory.
@@asilver2889 more of a belt and braces thing to help with airtightness between the board and the wall. The boards are squashed so tightly to the wall by the mechanically fixed battens I very much doubt any moisture that might find it’s way past a failed bit of silicone in 20 odd years will cause much of a problem.
Batten is wood ,even if doesn’t touch directly the external wall it still will souk in water cause of tiny confined space tape won’t help. Instead of wooden battens use drywal metal frames there are all kind of and sizes needed it’s basically same batten just never root will stay there forever unaffected and can be easily dismantled and reused. compensating tape that foamy one to keep gap between metal and stone,to avoid cold bridge, insulated plasterboard with sealing tape behind joints,or just simply two plasterboards (overlaying) to close all gaps.from inside or from outside as preferred install ventilation lots of possibilities. If u think can come up with clever simple nice looking points To keep the air gap dry and nice no more silly problems with damp and mould forever. That’s it.
And keep plasterboard edges away from touching ground and perimeter ,sides and top can be 1-5mm from bottom lift plasterboard 1-2 cm. Can be any by needs.it’s .to escape soaking from leaks. And will have space for flooring to go in under skirting or just small beadings. enjoy.
Not wanting to sound too unorthodox, one could simply not attach electrical conduits to the brickwork. Pull up sockets in the kitchen worktop instead and electrical trunking in the floor beneath kitchen cabinetry? Just a thought.
@CharlieDIYte fair enough. When you mentioned the back boxes interrupting vapour control layer etc it just reminded me of a project I did 10 years back in Muswell Hill. Getting perimeter insulation in between slab and wall is probably the most important aspect of these domestic projects. Making sure the slab doesn't act as a cold bridge etc. Humble Architect in Salisbury. Cheers
Thanks Charlie, as always, an open and honest debate covering pitfalls, alternative opinions, ideal solutions and then the rationale of the chosen compromise ! Some great information in this on a subject that is a minefield !
That was an interesting video. Only thing i would add to that spec' is a sheet of 11mm OSB behind the plaster board. Not that it will have any meaningful affect on either vapour or heat control, but it makes fixing things (shelves for example) easier. Nothing worse than trying to fix a 500mm wide wall cupboard that isn't widen enough to span between the studs or is wanted in a position that won't coordinate with the studs. Apart from that, i am with your design rationale all the way!
@@CharlieDIYte u put the vapour barrier staple to stud work thrn plasterboard and make air vents in wall so air can circulate which is what i have done and i habe a 100mm gap between wall and stud
Oh dear, this is how the plasterers did my last house in 2001 and I have just checked my current house and it is exactly the same. Well at least I know what the next job is to do. Thank you for your indepth analysis
You can ameliorate any problems David with a good vapor management strategy ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-NbtijHKy2Vo.htmlsi=PvttgPAugjQfCs01 👊
What's worth doing if you've removed all the internal plaster from the external walls. Put a tight coat of sand and cement render with a waterproofing additive, before you insulate and plasterboard yor walls...
Assuming Tom you don't want the walls to breathe. I would have agreed with you but I have tryolean on the outside so the walls can't lose the moisture outwards so I think I'm going to have to look into a strategy to allow it to dissipate internally through the insulation and (possibly intelligent) vapour barrier.
Aren't you going to get cold-bridging across the timber? That's why you'll see recommendations to use insulated plasterboard as a layer over the top of the battens, as well as insulation between the battens.
I just came to the comments to point this out, cold bridging through the timbers. You could end up with shadowing on the walls. Also, the 1x1 timbers could be omitted if you ensure the PIR between battens is fitted flush with the front face of the battens. I retrofitted IWI to our solid wall house using a similar technique but created a 30mm ventilated cavity behind the battens, essentially built stud walls internally in front of the brick walls. The house is very comfortable and retains heat well.
I had a large extension and the builder pushed us into getting the whole house dot and dabbed, standard plasterboard except in bathrooms, over the existing plaster. I really didn't want this and i am wondering what problems with condensation we are likely to encounter. Watch this space...
Ben, hopefully you'll have very little condensation as per my experience. My advice though would be to watch this vid ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-NbtijHKy2Vo.html and keep those moisture levels under control. 👊
What about PIR foam adhesive directly bonding insulation boards with walls (or insulated plasterboard)? I generally think that external insulation is the best method and I don't agree with your explanation as to why you decided against it. Pretty much the entire EUROPE is a case study for it, there are countless solutions from major brands available and specialist installers.... just not in the UK for some weird reason.
Hi Charlie, have you got any thoughts on insulating plaster such as Thermactive? Although it has an r vale of 0.037, by my maths it actually ends up being a similar build up to PIR given that you don't need a venting void or plasterboard or top. I'm weighing up the options for IWI in a conservation area brick terrace.
Use kingspan , use instastik foam to stick the boards to the walls . More efficient than battons, and no thermal bridging. Foam to fill gaps board to board and corners. The maximum load I have on a 8x4 is 200kg. I have been doing this for over 15 years and never had any issues. It's alot simpler one step application that maintains the vapour barrier and insulation. Preparation is key to get good adhesion and finish.
Thanks Henry. I'm kicking myself for not mentioning Instastick because as you say it's far superior to plasterboard adhesive. That said Kingspan still recommend mechanical fixing - do you do this? I know a lot of people don't but it's for fire regs compliance.
@@CharlieDIYte fire regs is a funny thing, if you used plasterboard adhesive on boards it would be fine, instastik has a B2 fire rating, so does have some rating, plus in theory you are putting a plasterboard covering on, if you put a 15mm mega deco board on your encapsulating the kingspan, you have impact resistance, fantastic fire resistance and the finish is so smooth. I have had the debate with building control about vapour barrier, adhesion etc, basically I took it to the head of building control, gave him the technical and they now support using it. I think the issue is that kingspan recommend mechanical fixing, due to they are looking at their product alone and not in conjunction with another product. At the end of the day in terms of fire risk, you are holding a insulation sheet on to a 9" wall , you don't need fire protection for the structure. I've used it in single skin garage conversions, 100mm kingspan, higher U value that the architect specified, takes me less time to do, I earn more money as I'm on price, very happy customer, they say it's the warmest room in the house. If you wanted to mechanically fix, you could stick your sheets , then put masonry screws with washers before the plasterboard goes on, a happy medium if in doubt. The key to sticking a foil sheet is preparation, weak SBR bond on walls first to cut down on dust and loose material, then make sure everything is sprayed with water. It increases the bond, plus speeds up the cure time. So far I've found instastik the best. Fastest cure time, so I'm not stood around long, it's more expensive than other brands, but it does the job.
Not sure about others but kitchens I recommend moisture resistant plasterboard on walls due to humidity and ceilings fireline plasterboards even on single storey extensions for the sake of the small extra cost its extra protection incase of a fire usually you have off cuts from covering the RSJ
I have implemented external insulation along with mechanical ventilation with heat recovery (MVHR) in my home. While it may not strictly adhere to vacuum requirements for MVHR, this combination has proven highly effective. The system functions like a charm, preventing condensation within the house and maintaining significantly lower humidity levels. This integration has successfully created a more comfortable indoor environment, showcasing the practical benefits of combining insulation and mechanical ventilation for improved humidity control.
Hello, what is MVHR brand you got installed? cost of installation? Does it work in conjunction with air source heat pump and under floor heating? thanks for the enlightenment.
I've been working on insulated my parents 200 yr old house, which has sold walls (only the ground level) with internal insulating like render. Called like green ultra. Only did this on the external walls. 20 yrs ago builder just dabbed plasterboard all damped over time. Now been removed. Can feel the difference think I got about 50mm of insulation in some areas as walls are not that straight. Bowing in areas trying to get it flat. Can feel the difference. Wouldn't mind getting a thermal camera to see the temp diff between the ground and top floor as top floor is still solid walls. With some plasterboard on some of the rooms.
Thanks for sharing - does look good where you're wanting to stick to lime render. How have you found building it up to 50mm as it looks like 30mm is the recommended max? 👊
@@CharlieDIYte The wall was pissed as a fart and bulging in places. The areas below the window for example the applied layed of insulation is about 25 to 30mm The recommended application is between 10mm to 30mm per coat, cured for a period of time, keyed at some point. After some time has passed another layer may be applied to build up the thickness. Which in my case was about 50mm. Would deff not apply anymore than a inch at a time as it may fall off... Taken a few weeks to get it to where it needed to be and it's almost completely flat now. 3 coats and some areas and 4 in others as i say parts of the wall bow and bulge. It was very easy to mix and apply. Its nothing ive ever used before. Its ever so light yet sticky. Think of it like bonding but its 10% of the weight, wonderful stuff if you want the building to breath. At the moment a small radiator is in that room to help get some warm in that room. The room is maybe 5metres by 4.5 metres with really high ceilings. It now doesn't feel as cold as it was before the insulation. The rad is only a tiny thing single panel single convector. 500mm x 500mm. Deff would recommend this stuff if 1 wants to let the building breath. It's letting the damp get out that has been covered by plasterboard for 25 yrs. 1 wall when I took off the plasterboard was damp to touch. Can see it physically wet. Just soaked my hand. Behind that plasterboard was some sort of square corrugated tar cardboard that I've not seen before. It is still drying out after a yr. Damp patches are appearing. But at least its not going to be moldy.
And I'm sure you already checked afew different areas on different walls to make sure the bricks weren't used as a fire stop at doors or any openings or not even fire stops just to hold the small dukes we called them ,bits of wood built in to wall centre to fix door frames Though as I say you I'm sure have thought of anything I could 👍
Not sure if you have it in UK but in NZ theres this product called Crystal, its a non decorative coating you paint/roll/spray onto concrete. The crytals in it actively seek out moisture in the concrete and it becomes a complete waterproof sealer. Typically used in existing subfloor basement concrete walls.
Thanks, that's really interesting. If nothing else could be really useful for the bricks below the dpc. A quick Google suggests we don't have it here though ..
@@CharlieDIYte bit lazy of me its called Crystal Proof. I believe theres many brands that make a similar thing but here its made by Cemix which is probably an Australian company. I believe most local concrete workers probably know the equivalent in UK?
We have something similar in Romania, but we call it glass water. You apply with a brush and roller and make the wall 100% waterproof and block water infiltration from outside to inside
Interesting video Charlie, but you made some statements that are wrong. You mentioned that the restoration lobby recommends just lime plaster, well that's wrong they recommend breathable insulation and lime plaster; contact the SPAB on how to do this. Secondly vapour barriers will immediately, or in time, be compromised and this results in a vapour rush and condensation, I have seen many failures of this kind. Thirdly plasterboard is gypsum and cellulose paper, perfect duo for growing mould and causing indoor air quality problems. Many housing associations are now taking out these plasterboard systems as they have failed. No amount of taping and VCLs will stop vapour over time. What you did get right was that EWI is the better option and should be the first consideration. It's disappointing that you dismissed other options without informed comment.
You make some very good points there and you're right I spent too little time on breathable insulation. It's a bit of a mammoth task putting these vids together and it's very difficult to cover all bases comprehensively. I think I'll be doing a second video setting this straight. Are you in the industry then? Wondered if you fancy a chat - ping me an email charliediyte@gmail.com I haven't finalised the insulation design yet so I'm open to suggestions that will minimise cold bridging and interstitial condensation whilst allowing me to install socket boxes and fix cabinets to the wall. 👊👌
@@CharlieDIYte Thank you for being open to discussion on these points Charlie. I will be emailing you to see if we can find some practical options for IWI. And yes, I was in the industry as an independent consultant, so it would be good to share some knowledge both ways.
Always External wall insulation if you can. Trickle vents on your windows. At worst a passive air vent. Life is too short to worry about minimal heat loss through ventilation.
Charlie, so the process of insulating walls internally seems a lot more complicated than I had anticipated. I have a tiny box room in the corner of the house so it is cold, but I don't want to lose the depth against the walls that you are doing. I don't even really want to lose say 1 inch of insulation + 1/2 inch of plasterboard. So, I am wondering if you have ever heard of any kind of insulation boards that do not have plasterboard over the top and that I could paint over, or even cover with something thinner to give a reasonably smooth surface - something like a reinforced wallpaper. It would be great if the insulation board were impervious to moisture in order to provide a vapour barrier. Maybe they make something like this for use behind tiles in a bathroom. I don't know. Anyway, what I am asking is whether you know of a method of insulating walls that will be as thin as possible, given that I don't really care about a perfect plasterboard finish.
You could check out products like 'Qboard' - which is typically used in bathrooms and can be tiled directly on top of. They offer several thicknesses (4mm - 5cm or so), are fully waterproof and provide some level of insulation (apparently). I'm not sure you could wallpaper them directly, but I suppose you could plaster then paint / wallpaper. Will it stop the wall you stick it to from building up moisture? I have no idea at all! Good luck ;)
Most of us are going to bother with external insulation! Everything else doesn't have as good cost to benefit value. Is cheaper, is faster, gives a better insulation.
Personally, I would step away from PIR products altogether and go the natural route. See, Mike Wye, Ecological Building Systems or Back to Earth sites. Many ways of tackling this that would eliminate the need for quite so much wood, whilst removing the concerns about damp.
Thanks, I appreciate you sharing that. Yes I haven't totally decided what I'm going to do yet. I just have a sixth sense that I'm not there yet on the solution. I'm also researching Aerogel. 👊
@@CharlieDIYte Excellent! :) Also worth looking at Diasen Diathonite thermal plaster. I've used it on a few projects and it's always gone down well. It means that you can run a continuous layer over the wall before fixing socket boxes too so that they have a continuous layer of insulation behind before bringing the rest of the surface up to the desired depth.
I hadn't got to that point yet but yes I should consider this, albeit with the vapour barrier and the socket boxes allowing moisture through anyway it's probably less important. For £3 a sheet extra it's probably worth it though.
i don't get it. the consensus is tat the most appropriate material is lime plaster right? your only issue seems to be, how to get enough energy to heat the rooms? surely its far cheaper to keep your gas boiler and just install solar with additional heat pump. that will easily be enough to toast any roo and the only additional cost is the solar and heat pump . the solar will run the heat pump so no additional energy costs
Can I suggest not putting any sockets in the external walls. You can get popup sockets or use an upstand thick enough to take a shallow box with the cables going down behind the units.
Hi Charlie. Interesting content, as always! You forgot the include a link to the thermal imaging camera - I'd be interested in getting one, if you could share the details of it. Cheers!
Great video Charlie. I'd definitely install an MVHR system if you can. I renovated a 1790 farmhouse in the French Alps, wanted to expose the stones but Mairie insisted on render so I insulated outside with Kingspan K5, (fireproof) and rendered over that, then lime plastered inside, external walls, plus lime wash paint. Dug down, underpinned and insulated the foundations, dug down rafted concrete floors on 300mm foamglas gravel then underfloor heated everything. The house is at 1100m, it's about 250m2 and costs about £1500 year to heat and DHW.. where the temp is -5 to -15 for appx 3.5 months whilst house is 22°. I'm a sparky but did the design, planning and work myself. Took a while mind you ! Love the channel....
Thanks for that mate. Wow, what a project!! Sounds similar to what I'm having to do right now with foundations missing on a corner of the kitchen. I've decided to go with breathable insulation inside now, given the exterior render isn't breathable. Also lowering the outside ground which will help damp issues on the walls.
@@CharlieDIYte sounds good, lower the ground and try and incorporate as much land drainage as possible. I like those humidity monitors your have, An MVHR will give you a finely controllable tool to manage humidity and hopefully stop any potential condensation before it starts.
@@CharlieDIYte Hi Charlie. I have the exact same problem as you, tyrolene render on the outside, solid walls. What types on breathable materials did you insulate with? In what order and method did you install them? Thanks
From a thermal performance pov you should not leave voids in your structure. I know this goes agains common practice in the UK and it's a more expensive option but walls need to be void free in order to minimise the chance of mould, cold bridging etc. I am not at all suggesting that you stick the rigid insulation to the brick wall. That is wrong and against manufacturer recommendations and will result in issues. You should however fill the void with some form of wool insulation. I have a personal preference but they will all work so maybe go for an economical option. If you are looking for other improvement of the design, maybe also use steel framing rather than timber. It's a bit harder to start and you will need to get a few more tools but the channel allows for insulation to be tucked in and the thermal bridging happens across the thickness of the steel profile which is substantially smaller area than the timber that you use. Also, once you get going, it's faster to build than timber framing. This likely goes without saying, but make sure that the outside of your solid walls is in a good state. If you have exposed bricks treat those with water repellent (many to choose from). If you have render, you need to ensure there are no cracks as those are ingress points. Lastly, I your slab was poured with insulated perimeter, I think you may be over engineering this whole thing. It's for you to judge but there is a point at which thermal improvements become exponentially more complicated and costly. I get that this is also content generation for your cash cow but ... edit: I can't believe I forgot this but I used intelligent membranes for a similar project with great success. And yes you can dot and dab over it and you will not get mould (remember to use a primer on top of purple and under the adhesive)
Thank you so much for sharing your experiences Charlie, it really is invaluable. I have a similar set of circumstances so it will be really interesting to learn how you get on with your approach. Best of luck with it all.
Hi . I dont see any update to this video in relation to the method you decided to use to insulate the walls, or have you a link to the update if it exists? thanks
Thanks for sharing your process, love your videos. Your focus seems to be on moisture from inside condensing in the cavity. Is there any concern of water from outside coming through? Other than protecting the battens with vertical dpc strips is there nothing else to do there, e.g. no tanking needed? Another thing I worry about are air gaps: I guess air gaps increase insulation effectiveness. But wherever air can flow, moist air can flow, so why not fill air gaps with foam? Just one missed spot tape would let air in no? If the dew point is in the middle of impenetrable foam wouldn't that be better?
As far as I can tell vapour doesn't just spontaneously condense in the middle of materials, even if this is where the dew point occurs, it has to condense on the coldest surface of that layer. I think Charlie is using an air gap at the back just encase there is any moisture issues with the solid walls then another on the PB side as a service void so he can have ridiculously deep back boxes.
It would be great to get an update on this project, as I'm considering internal insulation at present, having got cavity Wall Insulation that I'm waiting to get removed under Guarantee (ha, ha), so will need to update/upgrade insulation in my bungalow... I'm retired and can do most jobs myself, and obviously, internal insulation would be cheaper and easier to do (I think)...
Excellent Information Charlie, It’s a cost that you have to be prepared to lose some floor space to gain comfort as well as peace that your property is not rotting away behind the seems. I’ve no problem with loosing some floor space to do this but like everything else in life,,,,, Quality comes at a cost. Thank you so much for sharing, it a great reference video that I’m going to share with a lot of folks. 👍
Does the foil go to the outside or inside with gyproc , if inside wouldn't that cause damp on the outside to seep through the gyproc ? , I have lathing plaster and would like to strip plaster out and replace with foil backed gyproc on to battens with foil to face outside in kitchen with foil insulating sheets on to the gyproc then kitchen cupboards on to that , without the moisture issue it would be easy lol
I've just insulated a north-facing kitchen wall using 4mm cork roll, bonded, full contact, with tile cement (diluted 1+5/PVA+tile cement), to the existing plaster/wall. (The wall is a cavity wall). Hopefully this will mean there's no void to collect moisture. The result so far is signicantly reduced condensation, with a marked increase in temperature of the room. The cork was treated both sides with a diluted PVA 'wash' prior to application, to help with cement bonding. Is working for me!
That what I've gone for, but added 2 layers of SF19 - the 1st room I took off all the old plaster - but am not sure I'll bother for the rest (certainly upstairs), as the dust & dirt was silly! - not sure on the full results yet, as still to fit the radiator back in, but it seem to be working.
Just to understand that: Is it 25mm studs attached to wall with 25mm batts between (which ones will you (or did you) go for ?) then the SF19, then another layer of 25mm studs/batts and then the plasterboard attached to the studs ? Also, does the plasterboard need to be a breathable one to keep it all breathable ?
Hi Charliediy, really appreciate your video very well done. I see the batons represent a significant cold bridge. Did you consider foam glue ? I used foam glue which unlike dot and dab and batons is foam insulation so no bridge and it worked. Still need vapour barrier but again foam glue on phenolic. My new project we are using breathable Lyme plaster x 3 layers plus final coat of aerogel plaster which for 10mm has same u value as 75mm of PUR board. Phil
I do think this a bit of a insane project but hey it's good youtube content! ;D HAHA you going to end up selling your home and buy a run down house just for the content! ha
From Roger Barnes youtube video, "Escape to a French Fishing Port". Roger is an architect and working on an old stone house. To add insulation, he is adding 3cm of clay and hemp to the interior stone walls (sprayed on) and then covering with a lime plaster. You can check out his video, he explains it all (with diagrams) much better than i could.
The timber studs will just act as cold bridges? Timber is in no way comparable to PIR in terms of thermal insulation. I’m on a project at the moment where I will repoint the externalbrick wall in lime and also add a few air bricks then leave a 20mm gap internally and do 3x2 independent stud framewith 70mm PIR in between overlaid with 25mm insulated Plasterboard. Allows the external walls to breathe and keeps the insides toasty with vapour controlled by mechanical ventilation.
Another approach would be to use moisture conducting insulation. Any condensation that happens inside the walls would than wick to the inside and dry off. One would use stuff like cellulose or woodwool as insulation and woodpanels or clay-bricks as inner wall. Since i've heard of this concept I've come to the conclusion that breathable wall materials actually mean moisture wicking materials (it makes no sense being able to breathe throu clay or lime)
Indeed, I've been looking at wood wool insulation like Lime Green Warmshell, a system from Steico and most recently UdiTHERM NF. These allow vapour to move through, and help to contribute to the thermal mass of the room. Admittedly one does need to use vapour-permeable materials all the way through.
Yes Sascha, the term breathable really means 'vapour open' so that moisture vapour, but not air, can make its way through. It should still be airtight, confusingly. Many conflate 'breathability' with ventilation. I was baffled until I did the training and research.
Came across this video while researching how to repair a damp wall. Like you previous owner of my house has dot and dabbed standard plasterboards to a thick, solid external ground floor brick wall, and needless to say mould has penetrated the plasterboard and is forming on the walls. Over the years the external rendering, which would have originally been lime based, has been replaced with modern render, so the walls cannot breath properly. All in all, an absolute mess. I am at a loss to work out how I can fix this mess without incurring substancial costs. If you speak to 10 different experts you will get 10 different answers.
The problem with this method, as far as I can see, is that there's no air flow in the void. When condensation forms in that gap there won't be any air flow to dry it out.
There won't be any condensation because of the vapour barrier. I'll be doing an update vid shortly. Actually going with a breathable insulation system.
Fantastic video. I'm just wondering if it's worth all the effort, e.g. keeping the insulation boards off the wall underneath using the 1x1's, I know you want to have some aeration to combat any condensation, but any moisture in behind should be dealt with my the lime mortar they've used? What about drilling out some holes at a downward angle every metre so as to allow air into the space? The initial mould you saw might've been due to the paint finish and lack of vapur barrier, end of?
Hi Charlie i have been looking for this advice everywhere thankyou! I am doing similar but my walls have rising damp (solid walls) looks like it has been plastered not lime so hopefully once removed it will subside. im considering using dry rods as a chemical dpc before using said method you are doing any advice would be great?
Has anybody got any experience of insulating wallpaper? I don't have a water vaoour problem but have a cold room with three outside walls. Does it work? What's the best product?
Id gyp-line the walls with rubber gromits to reduce cold bridging. Use 75mm insulation on to the gyp-line , tape the insulation amd then board over ot. This ensures that there is an air gap for the brick to breath, but would do what you want
I would of put the timber on the wall then screw plasterboard to them. The two inch space is enough for air circulation and would save a few quid. Oh I'm a tight arse so that's my excuse 😉. If there's a two inch gap you don't need to worry about moisture transfer.
The old houses are not designed for any modern materials, the only way is to use vapour open insulation and lime plaster, Stud the solid walls, wood fibre or sheep wool between, wood fibre insulated 20mm board over the studs, then lime plaster with mesh. Would never use celotex or moisture control barriers. I would never bring a solid wall old property to today's u values. Gypsum, and cement are a slow death to the old properties.
Charlie I’m trying to insulate my walls myself. I was going to batton and then attach k118 to those. The walls/ old plaster board were damp and mouldy - do you think this will not solve the issue?
This is such a good video! The approach makes complete sense however I wondered if sealing the wall could trap rising damp? Or is rising damp not an issue at this property? I'm not trying to be clever here, I just have a similar challenge ahead and am formulating the plan!
The ONLY way to solve your mould problems is to simply open your windows slightly in the morning before you leave the house OR have vents/fans, if you never leave the house your heating bill will be slightly higher if you wanna keep it warm inside and its cold outside but no mould. Just get some fresh air for a couple hours a day in the house and no mould will ever form.
Man I’m totally lost after watching this video I have a wall that has a small amount of old insulation inside then lathe and the plaster has been removed I had bought the pink foam boards I was planing on glueing directly to the lathe then putting drywall directly on top of the foam board All this talk of mould has freaked me out , should I not put the foam board onto the lathe now? I’m assuming the lath with insulation behind it creates the gap that’s needed behind the foam board but can I attach drywall directly to the foam board at this point ? Or does there have to be a space between the foam board and drywall ? The old system had drywall right on top of the plaster and no vapour barrier and it was all good inside but now I’m wondering if the foam board will cause me a issue inside? If this idea is ok is there any point of adding a vapour barrier between the foam board and drywall? I’m guessing the foam board is my vapour barrier ?
i would defo put a special primer or waterproof adheasive on everything you show us in this video. all the walls, ceilings, corners etc etc you can buy double green plaster board and make sure to put them in the whole kitchen area and ceiling. why not make the framework out of alluminium? i would NOT take wood at all to frame in that place specialy.. you have a wet room dont use wood to build your frames etc. they make alluminium framing specialy for that reason, to use in wet rooms and for ceilings. the double taping the sides of the insulation is a bit overkill specialy if you use a wooden frame... waste of time and effort imo i would just use gluefoam and fix that kind of insulation plates. they have special lips on them to go over your framework or to overlap to another plate. you see so you would not need the tape what so ever. if you primer the walls make your frame pref allu in wetroom then foam fix your insulation put on your special double water protected plaster board. that should be a solid and efficient and low cost price way of doing it.
Thanks for sharing such in depth thoughts 👊 Here's what I actually did. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ou1CjwflZtM.htmlsi=fbcmgV6gmoapXQlw
When doing my bedroom i battened the walls and as the walls were so uneven i used plastic shims to bring them off the wall then used a closed cell expanding foam sprayed behind the battens to stop them flexing, reduce sound and act as the damp proof membrane. I trimmed back any spill out the side of the battens with an old saw then filled between with mineral wool insulation. Then went over all this with my vapour barrier and plasterboard.
That's an absolutely top job. Great work. Yes I've considered rock wool. It means having to install an additional vapour barrier as you say but it's not totally off the table right now. 👊
I have mold developing in the edges of my ceilings, can't seem to see the underlying reasons for it. Only thing can see is the roof is a low apex, there is continuous gap around the roof edges and guttering. Don't know what to do to deal with it. I can't get close to edges in the loft because the low levels and I tried to push insulation into the edges to, with no improvements.
