You SHOULD fill the cavity with expansion foam. Then add another 80mm of external wall insulation. Then so proper ventilation. If you have good budget then heat recovery system would be marvelous (not really known in UK but very popular in Europe).
Thanks very much for the very clear video. I have been conidering small polystere ball insulation for our 2" 1889 cavities but as brickwork and cavity are old and both southern and west walls exposed it does not seem like a great idea any longer. Espcially worried about it becoming a haven for nest-building, soil-raising bugs. Top man!
My house move (15 years ago) we had a very difficult buyer. One of his gripes was the house we were selling (1950) and zero problems did not have this cavity injected insulation. I told him what a bad idea that was, also (given the age of the house) I wouldn’t do it because of uncertainty regards the wall ties and interaction with the foam, plus the damp issues. He bought the house and told us he had arranged for the cavity insulation. He even told us the cost (thousands). Oh dear!
Very informative video 👍 When I moved into my 1925s semi, an authorised contractor from the Govt 'Green Scheme' surveyed my house - drilled inspection holes, etc. They advised not to have cavity wall insulation as it would encourage damp and they couldn't provide a guarantee. 6 months later, the Govt Scheme team phone me to check if I was happy with the work as they'd been in billed.... They didn't seem concerned that they'd been ripped off. Another friendly builder who usually renovates much older properties told me that old houses are meant to "breathe" - through the loft and down the cavities - and expressly advised me not to have cavity wall insulation.
Thank you for the advice just-in-time. I have been in the process of getting offer from a contractor with whom I slightly discussed about the potential benefit of leaving as it is since it’s air-induced insulation provided by the cavity itself. He fairly even mentioned the risk of moisture accumulation afterwards if the house has been over exposed to windy showers.. But regardless he was confident that it would provide thermal insulation thanks to its air tightness. That’s funny because it’s the same reason we want to avoid it as it would not enable ventilation when it’s air tight. Anyway, to me CWI is a clear No Go after all I read and finally upon hearing your detailed insight here. Appreciate it.
Thanks for this advice, I will be putting all of the insulation on the inside of my next refurb, I have had my suspicions about retrospective cavity insulation for years, may be losing a bit of space on the interior but then its going to be cheaper to heat. The advice on night locks is excellent especially if you have timber frame windows in a Conservation area, the planners/building control will usually accept the option over unsightly trickle vents that may be detrimental to a windows period appearance.
Thank you for your comment. Unfortunately as with most things, they rush these things out and don’t consider the consequences. Right now we are seeing a huge amount of cases of condensation and mould due to poor insulation and lack of ventilation. Night lock is a great way to ventilate but again although very effective compared with trickle vents they have deemed this a security risk. I now recommend passive vents as a cost effective solution
My house has trickle vents in every room, but also central mechanical ventilation. I'd say in such a setup, trickle vents are entirely sufficient no need to open the windows. The mechanical ventilation can be set at a low setting, or on a schedule, or in some cases can adjust its action when it senses more CO2 in the house. I think that's one of the best ways to control the air flow and moisture. (the only better way is to have central ventilation with ducts that has even better control over the flow of air to each separate room. A central air heat exchanger would be even better, as it would keep heat in the house instead of expelling it with the waste air)
I am very suspicious when the government tells you should do something like CWI !! I always done the opposite and so far I cant complaint. But your video is self-explanatory it makes lots of sense and you confirmed all the doubts I had. Thanks Buddy.
Yeah, i used to work in food handling. The government wanted us to wash our hands after taking a dump. We never did. If i wanted the govt telling what to do i would move to communist Rusia!!
I purposely dug my septic tank and the seep.lines next to my well. Damn Democrats think we'll get sick from mixing our drinking water with our sewer water. That's just silly. Stupid scientists with their PhDs. what do they know..
I agree that cavity wall insulation should be waterproof, I have had a retro fit in my 60s house of the beaded stuff its completely water proof and has a structure that allows air and water to pass between the beads. The thought that there is any cavity wall insulation out there that's not made of waterproof material in this day, when we have decades of knowledge, is mind blowing. I do believe PIR is superior, but I have yet to see a retrofit system.
We bought our final home, a bungalow in Enniskillen five years ago. It has breeze block inner and brick, I think they are Butterly, outer skin. I found out recently that it was built in the same year I was born, 1963, yet it looks like new. Anyhoo, we looked into getting a grant a couple of years ago and the guy turned up from one of these companies to do a survey. He drilled some holes and used a device to look inside the cavity. Turns out it actually had a thin polystyrene sheet type insulation that still left a gap. He was pushing us into getting that gap filled but after researching about the problems with houses in wet areas, we declined. The next year they were giving grants for increased loft insulation. We applied and were successful and the team of installers turned up to put the insulation in. Turns out they supplied sheep's wool insulation which is much safer to install and has better damp releasing properties. They also installed the correct vents in the roof tiles. The difference was amazing. In the winter we use a bucket of smokeless briquettes, and as the fire has a back boiler the whole hose is heated. Then we don't need to put a fire on until the next evening as the house now stays toasty. Not just that but last summer during the heat wave despite having a lot of direct sun, the house stayed perfectly comfortable while our friends' houses were like ovens. I actually paid for and installed sheep wool in our adjoining double garage roof space. Three times the price of Rockwall but worth every penny. We tried to tell my wife's older sister not to get wall insulation in their bungalow out here but they did anyway and commented recently that the house was no warmer. Bottom line - clear out the junk and get the max insulation you can in your loft, you will not regret it.
Great informative video. Really helps to discourage a huge mistake for people. Only I'd suggest changing the word 'installed' to 'injected', or 'post installed'. Mainly because most older houses with cavities aren't big enough for post installation on inner wall to allow a worthwhile 50mm insulation or more to leave a minimum 50mm air gap to outer wall to allow moisture to escape.
If you built a completely airtight home and ensured that every single part of the spray foam system worked in conjuction with each other such as HVAC staging, air exchanges, dehumidifiers etc.. That home would be much safer to live in, cheaper to maintain, and last much longer than a leaky "breathable" house thats pretty much at the mercy of the elements. We have to move forward in building science people. Just because there are insulators putting foam in places it shouldn't be, doesn't mean spray foam doesn't work and homes should stay leaky.
I agree to a certain degree Nicholas, but how much did it cost to heat a house with a good old fire back in the day? How much manufacturing when into that process? All of these alternatives consume energy, and require processing to create these products. How much greener is it really? That’s the question.
In my opinion, I would say heating a home with fire can be unhealthy and either requires gasses or a burn material. That material has to be sourced from something. If you spray-foam a home top to bottom, your home would not only last hundreds of years longer, but the amount of energy it would take to heat,cool, condition etc.. would be pennies on the dollar from the moment it was air tight until the building was bulldozed. I know individuals with 5,000+ square foot homes that spend around $100 a month on utilities and have had spray foam for 20 years now. If it’s done right, there’s nothing greener, nothing more sustainable and nothing healthier for us humans as well as the earth. At least to this point! Until someone comes out with a better idea. We cannot move backwards though. Check out Spray Jones. He’s a legend in my book.
Very useful video, much appreciated for sharing your knowledge. You do come across as a good, honest tradesman. I agree with the importance of heating, and ventilation of the home. I have a question, what do you recommend as an insulation option for a solid wall home without a cavity? Internal vs external, I like your idea of the insulated plasterboard, but what is the ideal size as to avoid these cold spots. Thanks, I've subbed!
I'm just about to have the cavity wall insulation removed that a previous owner had done. Having lived in my house for 7 years the damp problems have only worsened year after year. With 2 young children I want to live in a dry safe place. The contractor inspected today and found it was rock wool that is damp and I imagine saturated in places. Ironically had a damp survey done last year and it was one thing that wasn't even brought up but as far as I can see it is the biggest problem. Thanks for such an informative video.
Thanks for the comment Caroline, it’s a huge problem especially when we have long periods of rain in the winter months driven by strong winds. We are receiving at least 15 calls daily at the moment. Are you having any insulation put back in? as this often happens.
@Coastal Wall Ties Ltd no just going to leave the cavity empty. Having a log burner put in. It's an 1940s ex council semi detached house,I might see if the roof insulation can be replaced.
Cheers for the video, just had two guys round trying to get us to have the bonded bead installation told them that it had been checked few years ago and there's not enough space in between the walls when he drilled holes so couldn't 1930s semi
Glad I stumbled across the video. I have a house built in 1996 with an empty cavity, and after watching this vid, i feel i should just leave it alone. Winter is harsh however, would you be able to suggest or do a video on how to combat the cold winter months?
I've been in the building trade all my life and I'm now retired,however I have a comment. Cavity walls were never designed for air they were designed for moisture to go to ground. Bricks are porous meaning the cavity can dry out. All cavitys should be capped off at the top,there lies your problem with damp and cold,we don't have monsoon weather like india. Capping off the cavity is key! If you look at the weather forecast everyday it will show you humidity reading this is moisture in the air,it's raining but you can't see it and your roof fills with it. Opening your Windows is a no no because their may be less humidity in your home than outside of you open them you cause your own problem and the air condenses and becomes stale and mould and algae thrive,a cold or warm inner wall is what it needs to develop this has nothing to do with wall insulation but bad building. Inner walls are made with breeze block of thermolite block they breath but painted surfaces and vinyl wallpapers dont. The only way to allieviate this is by moving the air inside with a summer fan every now and then. We all cause our own problems within,boiling water,cooking,ironing,Etc everyone of us breathes out 4 cups of moisture a day add to that electric heating or open gas fire and you can see where I'm coming from!!
Thank you for a really informative video. I was about to inject polystyrene beads into my cavity walls so glad i now know about the Ant issue. I think im just going to go with dot dab plasterboard over the interior walls.
The best thing about insulated plasterboard is that you keep the cavity clear (preventing any bridging) and you also tackle cold spots I.e lintels. Thank you for your comment.
I have bought a house in Ireland where the humidity of the outside air is high, particularly in the winter, so I had to learn the hard way about condensation and mould. I have cavity bead insulation, I know because clumps fell out... Anyway, I have condensation form only at the top of the walls upstairs. It's like a straight line so I suspect the beads have settled. The manufacturers say they can't settle because walls don't move. I think that's balls - 20-30 years of passing vehicles should help surely. I only have storage heaters and a stove I think people here had a fire going all day and night to keep the damp at bay. Dehumidifier definitely helps, keeping a window open will only do so much when air is so saturated, plus its freezing. Looking at getting a top up but as you say everyone wants to do an extraction... And then refill. Ughh
Just seen your conclusions and there is nothing more you can say, I totally agree and was saying that for years... look at old brickwork books perhaps by Nash, he always says best forms of insulation in cavities is STILL AIR.... as bricklayers years ago we had to bridge cavity at roof plate level... and air bricks has a terracotta throat STILL AIR EASY Malc's in Perth WA ❤
Thank you mate, exactly the sort of information I needed. 👍 I live in a terraced house, built in 1960. Walls are two layers of breeze block, with a gap/cavity between them of about two/three inches. I was going to get cavity insulation as my quarterly energy bill was about £130 more than my fathers, who lives in a 1970s brick house, internal plaster board, and he had cavity wall insulation done (beads I think?) about eight years ago. I don’t think I will do it now.
I’m glad you found it informative, although it doesn’t really help you. You never know you may have a friend who is considering it and can pass on the information 👍
Thank you, if I can help people understand what I have seen over the years of doing this, and it helps them make an informed decision then I’ve done my job. 👍
I have a bungalow with a damp issue and after removing a few bricks I found that the insulation was bridging the DPC and was wet at that point. I’ve removed what I can and replaced the bricks with air bricks. I’m hoping that I’ve done the right thing? Fingers crossed.
The only thing I would be throwing caution with that is, by removing the wet insulation low down (yes, it removes the damp stuff) but it also means you now have a colder area at the bottom of the wall. In winter this could make the wall colder at the bottom now you have no insulation and air bricks feeding the cold air into the cavity. This could potentially cause condensation to occur at the base of the wall inside. My preference would be to remove the insulation completely but. you maybe ok.
Thanks for an interesting video, with lots of helpful information. I have a house that was built in the 80s and has cavity wall insulation in the form of beads - they must be not very bonded, which I discovered when my extension was built! I have to say, the old part of the house was incredibly warm, with no condensation or damp problems. I have definiitely noticed some cold patches have appeared since the extension was put on, though, and I lost a lot of beads during the build. The cold areas are where I lost the beads - unsurprisingly. I would really like to fill these patches with some more of the balls as I've had no problems with them, apart from when I had the work done. I'm now in a position where I cannot have my heating on through the winter and need to get these cold areas back up to the standard of the rest of the house. I would like to do it myself, but am unsure of how to. Have you any ideas? Many thanks.
It wouldn’t be an easy task to undertake on your own and can only be done via a contractor really. I would call the installers and see if they can help.
I'm so baffled!! About to sign a contract to insulate cavity wall in my terraced house. Read and listen to so many contradicting points. My friend structural engineer said to do it. My other builder friend said do not do it! Building is EPC D insulation would take it to C. I am actually afraid to do it now.... Obviously is through gov grant.
The only real benefit you’re going to get is the epc rating being higher. The choice is yours really but I would consider whether the risks out way the reward. How exposed are your walls to wind driven rain and is the building in a high exposure area.
Hi My house is from 1988 and it is a big house. I just bought 1 and half years ago and i got big disappointment because i keep having sick in winter time due to the cold and freezing house and i keep paying high bills so i was thinking to get a external wall insulation so would you suggest that to me or what is your suggestion to me at this point please? Thank you very much Regards
Brilliant video. My neighbour is just having their walls drilled and pumped with insulation at this very moment. We’ve let the guys put their ladders in our side but that’s as close as they will come to our walls. Our houses were built in 97 and heat up and breathe nicely, can’t stand these sealed new build boxes. Told them we’re happy as we are and don’t want any work doing
Good advice ... would have been useful to have a few bricks on the table in front of you to explain the detail. However, my take-away is do not retrofit cavity wall insulation of any sort!
Great very formative video, wish had known the risks with CWI, I would of not had it done, Was done 2009, 1960s property , wool not seen any issues yet, quite a few houses on my estate have had it done, anything government is pushing through need to take a step back and evaluate the product,
Thank you, yes that’s exactly my thoughts, just because the government and bba (British board of agreement) approved it doesn’t necessarily mean it’s a good product.
Hi, we have a 1995 build home with an empty cavity. I'm not sure how wide the cavity is, but we are thinking about getting cavity wall insulation. Would you recommend this? We can feel cold air coming into the house in many areas so the cavity is clearly getting cold air blowing in. We have been recommended Knauf Supafil 40. Any advice is gratefully appreciated!
I would think long and hard about installing a mineral fibre into the cavity. EPS beads are better but in all honesty I would look at where the draughts are entering and rectify that first. Cavities are best left clear if you can.
Im looking to build a new masonry constructed house detached, 150mm cavity and its planned to have 100mm pir in the cavity. Mvhr inside mechanical ventilation air tight. Lots of people on forums are saying they cant bekieve anyone has an empty cavity these days and new builds should be having full fill eps blown beads. Ill be avoiding that now then. If i can afford it, I'd like to add insulated plasterboard to the inside too but how thick would you recommend? I cant go too thick but but dont want to waste my money going too thin
6 years ago got a window replacement job , 5 windows , front elevation , very exposed , internal walls very wet round reveals , took me 5 days to fit them and remove 40 bags of white foam cavity insulation , you should never fill a wall cavity , its there for a reason , a house has to breathe , we are building sealed boxes , should be banned , the problems it causes are house destroying
Hi Alex, I appreciate the video you have done given great advice for us clueless consumers. My property was built in the 70s & my parents had cavity wall insulation back in 2000 believing it to be (mineral wool) blown in. Over the last 8 years i have been getting damp with mould in sections of the lower part of the house & also looks like some sort of foam or salts as i think its called with it, i believing Is thats its sodden when the rain hits, thats where it soaks back into the mush & given me damp. Do i need to get it repointed “gable end is something like 65 square meters” or just repoint the holes they made to put the insulation in or would it be something else. Would appreciate a little advise 👍 thank you
Thank you, I would divert your attention from the repointing as this is generally cosmetic and a cavity is there because moisture naturally penetrates through the outer bricks and mortar. My advice would be to get a builder to remove one brick on the outside where the damp is at its worst, check if the insulation is wet. If it’s wet then the best thing to do would be to remove, if it’s not, then you would be looking at condensation. Trickle vents or passive vents to increase new air flow and a consistent temperature day and night in the winter months would help this.
Really good video, thank you. Our house was built in 2003 and has Polystyrene 'boards' attached to the blocks in the cavity leaving a residual gap to the brickwork i.e. the cavity. A local installer is recommending filling this with beads so presumably you would advise against this?
Thank you. Yes I would avoid at all costs, it really isn’t necessary and the gap is there for a reason. The contractor is clearly just after your money as it already has insulation.
The beads are one of the best types out there, but they still have disadvantages. The beads themselves are waterproof but moisture can still reside on the beads themselves. Problems with the bonding of the beads seems to be an issue and unfortunately most cavities are not throughly inspected prior to the installation. I would read the guarantee with a fine tooth comb.
All I can say is, my house is a late 1950s house, I had rockwool cavity wall insulation fitted ten years ago and it transformed my house, much warmer, saved be hundreds on gas, and no damp.
You say that EWI (External Wall Insulation) is fine, would I be correct to say that you have no experience of dealing with issues created by EWI? The problems caused by EWI is now eclipsing the problems created by CWI i.e.: EWI is not impact resistant, once damaged moisture penetrates and the insulation is soaked and needs to be removed (unless you use flammable oil based insulation boards). Roof lines & gutters need to be properly extended in order to overshoot the EWI. If, instead of extending the roof etc., plastic trims are used at the roof lines then these fail especially when the mastic or silicone used as a sealant eventually fails (5 years or so). The insulation manufacturer's warranty requires all interfaces and junctions to be checked at least annually, this requires scaffolding at the roof line level of a 2 storey property. If you don't do this, then when problems arise, you have no warranty. EWI manufacturers warranties also specify that the render needs to be cleaned every 2 years without any agitation or scrubbing of the surface. I haven't found a cleaning product which can do this. So, no warranty again and the render is tear-stained and/or mouldy. I am a surveyor for a social housing provider who had Government grant funded EWI installed at thousands of our properties around 10 years ago. I am dealing with the above issues every day. If you have solutions to our EWI problems and believe that EWI is ok, please let me know. Otherwise you may want to edit your EWI recommendation .
Thanks for the comment and no I would say that predominately my work involves looking at cavities as opposed to external render. I knew of contractors failing to remove services from walls but the information you have provided is very helpful to myself and others. Maybe you should do a video to help consumers thinking about external render 👍 I appreciate your comment.
Hi, interesting article, I have a 1929 house with poly beads, seem to not be glued, and damp patches on the south and west facing walls, west facing room, I leave a window open on the night lock, still get the damp, south wall room has a trickle vent, room is so cold now, still damp. Resort to a dehumidifier to remove moisture from the air. On here to see how to or whether to remove the poly beads. Thanks for the video.
Thank you, my advice would be to arm your self with some loft insulation that can be torn by hand, and open up externally where the damp corresponds internally. Use the loft insulation to stuff around the opening so that you can inspect without the beads flowing out. Look for any solid bridging of the cavity or any damp material within the cavity, you can then decide on how to proceed.
Hi, thanks for this video. We have a brick build house with empty cavity wall and plasterboard internal walls, the bedroom is cold though, could we get round this by just adding insulated plasterboard onto the internal walls?
What exactly are the disadvantages of a full fill cavity wall insulation on a new building, if done properly? I'm thinking about a hybrid method, so I can have both thermal and acoustic benefits (outer masonry leaf >> spray foam or XPS+sealant (air and vapor barrier) >> mineral wool >> inner masonry leaf).
What a superbly informative video!I've used storm dry seems really good. This is the thing all the greeno's and government keep banging on about insulating everything, but none of them seem to understand that so many properties are all different in so many respects and they don't want to admit that in alot of cases could do more harm than good. I'm all for saving energy but at the same time don't want to end up living in a mushroom farm. 🤔
Exactly David, I’m sure the insulate Britain protesters haven’t got a clue about the disadvantages, or the lies that are fed to wriggle out of compensating those who’s properties have been affected.
Hi Alex. A very informative video and enjoyed other videos on this channel. Do you cover as far as Eastbourne for wall ties? Please let me know and I'll give you a call. Cheers.
Hi Neil, thank you for your comment, occasionally we travel to Eastbourne but we may not be as competitive as a local business. If you send me an email via the website I’ll see what I can do.
Excellent video. I think a quesiton my property has no cavity its solid brick wall. Should i use insulated plaster boards that have polystrene on the back of them with a damp proof memberane that comes between the brick and the plaster board. The only thing is i cant attach it directly via dot and dab so ive read. Or should i go the road of fixing battons to the walls so the plaster board attachs to the wood atleast then it gives some gap between the insulated plaster board and the brick.
Thank you, if the walls are prone to damp coming through, it wouldn’t be a good idea to dot and dab. Again if the walls are prone to damp penetration it would be advisable to consider a damp proof membrane strip behind each Batton. Remember to keep your gutters clear and flowing correctly on solid properties to avoid prolonged damp on external walls.
Exactly, don’t get me wrong on most new builds it’s fine where celotex is used and a cavity is still present. They have also been designed with adequate ventilation, but older properties are different.
Very good video. Thanks for sharing this! I am about to write my dissertation on cavity wall insulation failure. It would be interesting to have a chat with you and discuss your past experience.
I had cavity wall insulation in my last house (fibres) with no problems in the 15 years of ownership. The current house I have is 70% solid stone 500mm thick wall with no issues at all. 30% of the house is an extension with cavity walls and this part of the house smells musty. Especially musty behind wall hanging pictures. Wall gets very little sunlight due to trees but windows are south facing. I'm having a survey today funny enough for thermabead to be installed.
Every property is different and especially when solid walls and cavity walls are combined, the differential temperature will have a dramatic effect on where that excess moisture goes.
Hi, thanks for this useful video, very helpful. I have the blown wool type in a 1960’s bungalow, cavity’s were done about 20 years ago. Would you recommend removing this and leaving them empty? My house is cold now, but will it make it colder and have more cold spots on walls?
Hi Matt, thank you for your comment 👍 If your not experiencing penetrating damp or mould growth due to high humidity levels, I would consider looking up the insulation installer if you have a guarantee, and have them check the walls for voids in the insulation. I wouldn’t necessarily remove the insulation if it’s not causing problems. Do you have new windows? Also do you know how effective your boiler system is, i.e do the radiators work well? Is the boiler over 10 years old? Where are you in the country?
Live in housing assoc flat. They have just installed the bead insulation.Balls are everywhere,now the installers "Dyson",want to put electric ventilation units in each kitchen...right next to the windows. So do i open a window for free ventilation or do i turn on the electric vent NEXT to the window and run up my electricity bill???? Claiming its health & safety,well my kitchen window is open every day all day for free. Im not turning on any electric vents.
‘Nail on the head’ flats are prone to condensation issues due to the small surface areas, even prior to insulation. Insulating and then putting in a PIV system in every flat is crazy. I will say at least they have done that and not just insulated, otherwise your walls would be running. Keep your windows on nightlock and turn the PIV off. 👍
Try dehumifiers: particularly useful in kitchens, which generate a lot of water vapour (from boiling kettles, cooking in saucepans without lids, even bowls of water will transpire into the air). Dehumidifiers with compressors (refrigeration technology) work best in warmish rooms kept to habitable temperatures: they cool damp air to precipitate water vapour into water, but expel slightly warmed air. This is a benefit in winter as it reduces heating costs, not least as dry air requires less heat than the same volume of damp air, to raise them both to the same temperature. However, air passing over metal or plastic fan blades becomes positively ionised (which creates "sick building syndrome" in buildings with exclusively mechanical ventilation). So, if you use a room dehumidifier, also use a negative room ioniser: to offset the effects of fan-driven positively ionised dried air expelled from the dehumidifier. A 180 - 200 watt, 12 litre rated dehumidifier with 2.3 litre tank will actually extract something between 7 litres and 10 litres of water per day, if emptied three times: to keep air at 50% to 70% relative humidity in a very damp room. Mould will only grow above 55% RH. In cold or very cold areas (eg unheated basements) dehumidifiers with compressors do not work efficiently as the air is already too cold. Dessicant dehumidifiers are more efficient. Dehumidifiers on castor wheels are easier to shift around, as they tend to be quite heavy.
Hi I wonder if you can help. I’m in a council flat, it’s ww2 but was very cheaply and purely renovated 14 years ago. I’ve got rats in the walls , worse rat mites and ticks are getting in , basically the block in quite a few flats is infested. Obviously the council won’t to a thing not interested, what can I do ? Can I drill holes in each plasterboard wall and tip in permethrin powder ? Or something? I wish I had money to fill the cavity with with something recommend but no doubt it’s all pricy . What can be done ? Do you think it’s filled with those balls u said create critter issues ? Is it really expensive to fill even just a bit of the wall to stop the rats getting near to pipe work? ? Thanks kindly
I need some advice and hopefully you can help me. I’m have just bought a property which had cavity wall insulation installed in 2008 with a 25 year warranty. There isn’t any internal damp issues at present, however the surveyor noticed horizontal cracking, which after further investigation I found out the wall ties are starting to corrode, but according to the surveyor they are in the early stages of corrosion and will need some remedial work but it can wait until the spring. Could it be possible the insulation has caused the wall ties to corrode and what would you suggest I should do to remedy the problem. Would using a brick cream help with making the bricks more waterproof and potentially prevent the wall ties corroding faster.
Hi, the part of the wall tie that is embedded on the outer wall is subject to corrosion due to the weather, having cavity wall insulation just means that it potentially will allow more of the tie to rust. It would be a good idea just to have the ties replaced as a masonry cream would only slow the process down.
Hi Alex my house was built around 2005, with polystyrene sheets filling half of the cavity, I am considering BASF Walltite so it goes in as a liquid and then hardens like an expanding foam, so this would be closing the cavity, installer is reputable BASF certified etc, and not the knock on the door types. Is this OK or still a bad idea, we have the insulated plasterboard on the inside of most exterior walls, but the bills to heat are still substantiall and we may install solar panels / ground source heat pump soon, so I want to get insulation as good as it can be before we go down that route
Hi Brendan, it’s difficult to say if this is a bad idea or not really, how big is the remaining cavity? Are the wall ties in a good condition currently? Would they boroscope the cavity in many areas to check for mortar snots on wall ties and bridges above dpc level? Can they provide a copy of the guarantee prior to installation? If so, read it with a fine tooth comb. Another question to present them with is will the resin part of the foam melt the existing polystyrene batts? I do know that because the foam will stick to the bricks it would certainly increase its stability if the ties were to fail. Would it benefit you in terms of thermal efficiency? Possibly a little. I have been talking to a gas engineer who has had heat pump training who mentioned that heat pumps save you very little when compared to gas and they need replacing every 10 years. Solar panels maybe the way forward.
Anyone can apply stormdry, just remember not to spread it too thin as it soaks in easier than you would think. All you would need is a masonry brush and some dry weather.
@@CoastalWallTiesRustington thanks the reply i have brick house with a section of masonry painted white in the middle , would i use storm dry on both ?
In our previous council house we got damp and mould all over the house after cavity was installed. Called the council, inspector looked around and said we need to open windows and it will stop. We got cavity to keep the heat in and you want us to open the windows to let that heat escape? Yes that's how you fix the mould and damp he said. We moved out.
Thanks for the comment, unfortunately insulated or not you do need some ventilation in order to prevent mould, but in some cases, certainly when a property has a smaller surface area, having cavity wall insulation installed will intensify the mould issue.
Very informative video. We’re buying a house that has cwi already and I suspect it may be wet in some places as one wall feels damp inside. Any tips on removing cwi?
Alright m8 quick question for ye understand using the pir insulation rigid board clipped to wall ties and you still have a vented space what about the rock wool bats when blocks are 100mm each skin with 100mm cavity filled with 100 ma insulated rock wool the stuff is getting soaked when the house is getting built so how can it possibly dry out when there is no air flow it’s not rocket science but is still a common building method in the uk why!!!!!!???🤷♂️ keep the informative videos coming 👍
It’s a good question, and if it does cause damp it’s really hard to remove. It should dry out naturally from the heat in the house but depending on how wet it is, will have an impact on how long it takes to dry, and it also depends on whether or not the insulation is getting wet from external rain penetration. It is absolutely bonkers that it can be loose filled into cavities and full fill insulation can be installed knowing what we know through evidence. If it’s got to be done for energy efficiency then an air gap still needs to be present.
Mate solutions, a sealant on external walls , some last 4years will repel and protect all external walls from moisture, And as for ants borax injected into the cavity of any very little would be needed to repel any ants ect from entering the wall cavity, I think these solutions can definity work to improve this issues your addressing 👍🏾
Thank you. Could you do a video on explaining why every winter my daughters external walls in her bedroom get cold and damp? She ends up with mould growing on them. Our windows get full of condensation every winter too. I’m using a dehumidifier which helps the windows but my daughters wall still grows mould. A video on external cold walls would be great. We did have cavity wall insulation about a decade ago.
Hi Julie, what you have is condensation occurring, if you have the window in the room on night lock consistently and the thermostat at a steady temperature during the day and night, it should stop this from happening.
I wouldn’t recommend any personally, but I would be very thorough in who you choose to survey and install it, if you go with bonded beads. It’s important that you are given information regarding additional ventilation requirements suited to your property size. Cavities should be throughly inspected for any possible bridging or defects prior to installation and thought should be given to the condition of the wall ties and any possible alterations that may affect the 25year guarantee issued.
@@CoastalWallTiesRustington I was looking at a company called cavitech. I need to see what is in the cavity first and go from there. Cheers for the response.👍🏼
Thank you so much. I was in the process of getting cavity wall insulation, but not anymore after watching this video. I use dehumidifier throughout day n evening and each morning open all windows. Do I still need to use the dehumidifier during the night? Thanks
Hi Shahin, thank you for your comment and question. You shouldn’t need to use the dehumidifier at all, if you take a look at our video on condensation it will give you tips on how to prevent excess humidity. If you have any further questions please let me know and I can help further.
Thank you so much for your advice. I am thinking of having external wall insulation over my cavity wall. I have been told I need to have the cavities filled first. Have you got any experience of this? Thank you
Hi, I don’t think it’s necessary to insulate the cavity and have external wall insulation, it sounds as though the company maybe trying to get more money from you. External wall insulation is an option where a cavity wall isn’t suitable.
Great vid. Thanks 👍. Question “. We are in process of removing white wool ( very damp ) from our 50 mm cavity !!!! Our. Outer walls Are bottom Third Section face brick then rendered Con blocks upwards , with term blocks internal all walls , ,, Would you agree to installing air bricks at various points around bottom brick section , regarding some air flow or would this increase moisture In cavity on inside course in winter , not sure if would help !!! Air brick / yes No. Thanks
Thanks for the comment, the only reason to install the air bricks would be to dry the internal wall quicker, but as we are entering summer I would say it would do fine naturally without air bricks. So to answer your question no it’s not really necessary and would make the bottom of your walls colder during the winter period.
Hi, do you think external solid wall insulation is any good? I am thinking of getting it done but have heard lot's of bad reviews about it. would appreciate your opinion/advice. Thanks
Hi, the only thing with external wall insulation is that things like gas boxes, waste pipes etc will have to be moved to ensure no cold areas are left not being insulated. It may also be worth considering that this type of insulation method has not been around that long, so the longevity of the render etc is fairly unknown. It would be wise to ask to see the contractors guarantee and thoroughly read the terms, some guarantees have been known to include a clause in which if you attach any fittings etc to the external wall, it will invalidate the guarantee.
@@CoastalWallTiesRustington Many thanks for replying promptly. I heard that many customers had bad experiences with external wall insulation where water started penetrating, render coming off, internal damp issues etc. and as you probably know once they have completed the job even though you covered with guarantee they don't want to know you and will make excuses and someone like me doesn't want to the hassle to make complaints/ courts etc. It just takes ages and you may not get anything at the end. Have heard any negative sides or personal experience of solid wall insulation? because once it's done and problem starts, it will be very costly and inconvenient to remove it.
I haven’t had any problems highlighted through our company, but I would consider internal insulation plasterboard inside to the external walls of the house only, this would avoid the potential problems highlighted in my last response and avoid any issues with guarantees etc. All you need then is a good plasterer but it would involve plaster-boarding the entire wall, so things would need to be removed to ensure no cold spots are on the walls.
What about external insulation on a cavity wall then render? Just moved into a 1935 bungalow, cavity wall, needs render replacing was thinking of doing external insulation at same time? Worth it or am I setting myself up for problems further on
External rendering is the one of the better ways to do it because it would cover lintels etc, whereas cavity wall fill doesn’t. My only advice would be to ensure that you have adequate ventilation at night during the winter by opening windows on night lock to prevent condensation and mould. At least with external insulation render your cavity is not bridged. Hope this helps.
Also being a 1935 property if you decide to get external wall insulation, get them to check the condition of the wall ties first, the last thing you want after rendering is cracking to occur.
I've got a problem where the walls are getting increasingly colder each winter. My house was build in 2007. There are bricks both on the outside and inside. The cavity in between was insulated from new with glass wool batts I believe. What is going on?
I would remove a brick on the outside of one of the coldest walls to check the condition of the batts and to see if they are dry. If the outer surface of the insulation is moist but the rest is dry, you could try applying stormdry masonry cream to the brickwork, but I would wait until late spring/summer to do this to ensure the bricks are as dry as can be and to allow the batts to dry.
@@CoastalWallTiesRustington Thank you. I'll try that. After stormdry masonry cream has been added do you still advice against having insulation blown into the cavity? I worry the glass wool insulation was either poorly done or that it sunk over time
If they are full fill batts then it would be a job to remove it and it shouldn’t have sunk. If it was whitewool loose fill then I would say get it removed and see how it goes without insulation.
@@CoastalWallTiesRustington They are full fill batts. But I believe it's those fluffy glass wool batts that collapses and looses its insulation abilities as soon as they're exposed to any form of moisture
Oh im so confused - my semi detached has has just been assessed and I can have a new baxi boiler, loft insulation also wall installation injection route. What shall I do, has anyone had this done etc
If you can get away with just the new boiler and loft insulation, I would do that. Enquire with the company about adequate ventilation to the loft space as well .
@@CoastalWallTiesRustington thank you will asked them. The insulation the inject is called 'oil based bond beads' is this like the old stuff what they pumped into
I would assume that the external wall of the garage is a single skin wall, rather than a cavity wall construction. If it’s single skin then you can either insulate internally or externally but the external finish would be a render or cladding. The same would apply to a cavity construction if you were not wanting to bridge the cavity.
Hi. Can you clarify which kind of insulation you are speaking of please? Ive just seen a video using a kind of expanding foam which i would have thought would work ok as its waterproofing? Are you speaking of the old feathery type stuff?
So all retrofit cavity wall insulation has different problems associated to them, with expanding foam insulation, 1 type sets solid and the only way to remove it is by taking the outer wall down, others can disintegrate/shrink overtime. The expanding foam that sets hard would certainly be waterproof but please be aware that once installed it’s hard to remove if you needed to.
A cavity is best kept clear, thermal beads can be a pain, when altering your property the beads can escape out of the hole and essentially create a cold area in comparison to the rest of the property. Also if the property requires wall tie replacement at a later date and you experience damp problems, the insulation guarantee may become invalid. The best way is either a masonry cream, insulation backed plaster board internally if possible or a external insulation system. Hope this helps.
@@nadiaw978 this is a bit of a myth as well. Areas of wind driven rain as dictated by the BRE map are at higher risk of penetration but these products have never actually been tested on older properties. The BBA certificate shows that the test rigs used are that of 1984 building regulations - how can 1930 and 1950s properties meet future standards. The BBA also failed miserably to install mineral wool in a new construction nottomyhome.blogspot.com/2018/12/abject-failure-of-mineral-wool-and.html . No longitudinal test or product failure registry - no part of government tracks even the number of extractions per year and which product or types of property has failed. It's a poorly regulated industry and CIGA just tries to blame the problems on home owners - no incentive to do a root cause analysis of failures.
Unfortunately I’ve been affected by a company called heatwave energy solutions who have put cavity wall insulation. It’s caused damp throughout my house and I’m not sure what to do. Could you please advise? Thank you
Hi Adam, sorry to hear that you have a damp problem. Have you contacted this company to rectify? Have you got a guarantee backed by CIGA? If the company doesn’t respond and deal with your claim, then go straight to CIGA. CIGA will also try to avoid compensation but be persistent and demanding. They will probably send a surveyor round to assess and worm there way out of a full extraction but just be persistent and don’t take no for an answer. Has it affected all walls or just south and west?
The benefits of cavity wall insulation installed correctly far out way any negatives. If you have a clear cavity above 60mm in your home get it filled with bead insulation. It’s crazy to run another winter without your home correctly insulated. 270-400mm in the loft also.
Cheers for the info, was considering having CWI , but couldn’t find much reviews on it, perhaps maybe when we do an extension we’ll go for the foam backed plaster board, & perhaps silver backed poly insulation under the floor boards ? I did consider the outside wall insulation but it’s so expensive to do . Thanks again 👍
Good choice, just remember to ventilate your property as well and you will be fine, most new windows have a night lock in which you can open the window slightly and lock it, this will be sufficient ventilation.
Coastal Wall Ties Ltd Cheers for the tips, our main problem is the conservatory at the back of the house/kitchen diner, it unbalances the heat , luckily we’ve got a double glazed door so can shut off that area, hopefully we’ll knock it all down & put a new extension on the back . & retrofit insulation where possible. As I’m happy with my Oil boiler , don’t want to go down the ecodan heat pump rabbit hole. Don’t think my house would be suited to it. Good luck with the channel 👍
Hi Almaz, unfortunately I couldn’t recommend any retro fit cavity wall insulation, some properties are ok with it but I wouldn’t recommend taking the risk. A company called Wycamol have just brought out a insulation product called TIWI it’s a thermal insulation paper used internally. Keep the cavity clear is the best option.
I’ve had a company come and look at my house through the green homes grant, they’ve said I can have my cavity wall replaced with the beads. My property is 16 years old and has cavity wall insulation but I’ve been told it can be upgraded via the scheme.. what are your thoughts?
If you have already got cavity wall insulation installed and no problems then I would say don’t bother, they are just out to make more money under the green homes grant scheme.
