warm roof, cold roof, hybrid roof, they all work and have their bonuses! you don't have to follow the way we do them but heres my take on them. and ive not had a bloody hair transplant ! :-)
I'm in the early stages of a garden room build right now (almost cleared the ground, but have a bunch of materials ready to go). "tradies" have been telling me to vent my cold roof and the additional costs are ridiculous, not to mention the fact I'd need to lose internal head hight. Thank you for this video, and for all your videos. They've been a great source of inspiration and information for me as I've been planning and designing my room.
With this amount of explaining it just goes to show how passionate you are with your company and workmanship, keep going an ignore the haters, beautiful sheds🤯👍👍
for those people interested in the hybrid roof discussion there are 3 key potential issues: 1. Difficulty of creating a 100% full vapour control layer on the warm side. 2. Thermal bridging 3. Hybrid designs are untested by the insulation manufacturers, so architects / surveyors / building inspectors don't like them and don't specify them. However, in the context of a garden office, the construction on this video is, in my opinion a perfectly valid compromise. Yes there will be a bit of thermal bridging, but is that likely to cause condensation issues? Timber is a reasonable insulator so the chance of the inside face of the joists being below the dew point is pretty rare. The somewhat bigger potential issue interstitial condensation due to vapour getting to the underside of the OSB - Ideally foil tape should be stuck on around each joist and covering a bit of the celetex - that creates a vapour barrier. To be honest, on house extensions there is far more risk where a cold roof has been specified and the roof is not adequately ventilated (or downlighters penetrate through the insulation to the cold space. In these situations a hybrid roof with say 100mm in between and 50mm cover would be a far better option. I think this Oakwood garden rooms channel is fantastic, some great ideas and I bet the customers are very very happy. I used to manufacture and install top end hardwood orangeries, so much of this construction is familiar.
When I seen this notification pop up I initially rolled my eyes , here we go again I thought 🙄 But having read this unbiased comment I’ve gotta say, this is constructive and well written. Thank you for your input and I will definitely be using the foil tape going forward. I appreciate it’s not perfect but I’m these situations it works. Thank you for your input 👌
@@thegardenroomguru many thanks for your reply, having read through all the comments about this video you posted, I thought I'd add my 2pence worth which hopefully provides some balance. I can see from your videos you have clearly honed your construction methods and details to produce a great product for efficient commercial production and it's very generous of you to share.
There was documents from LABC maybe 10 years ago that had some variants of a hybrid roof that had insulation between, pushed to the top, then ABOVE the joists. Thinner than a warm deck, doesn't need venting, but I agree not one other architect I met wanted to work with it - insurance purposes.
Excellent explanation. Ive literally just finished my roof timbers and chose this system just to get the extra head room inside, as a warm roof just robs you of height. Well done great vid.
Always interesting and learning alot, great of you to share your knowledge and methods. I plan to build one myself in the future and without your vids I wouldn't even entertain the idea. Big up Geez 😊
I’m not a builder, joiner or anything to do with the construction industry but I love your bluntness, well you are Yorkshire, your efficiency of working and the finished product. Keep on keeping on !
Hi Liam I’m a general builder and have used your system and I can assure others that it does work, no issues ever in the many buildings I’ve done in the south west. Keep up the good work.
Used this system on a flat roof garden room with 8 x 3 joist put and angle fillet on top of the joist to give the roof some fall for the water, full filled with 200mm insulation ,vapor barrier and foil backed plasterboard. Was so worried about moisture after 8 years took a piece out to have a look and was as dry as a bone.
Mirroring other comments, ignore the haters, leave them to dwell in thier pits of misery. Your vids are informative, concise and occasionally funny. They break the monotony of other posters formats and I for one look forward to them. So a big 👍 for cracking builds and videos.
Thanks for that mate VERY helpful. I know nothing about building anything but got a lot of common sense and the way you explain stuff makes perfect sense to me. Good on yer.
I’ve heard you make a point about people trolling and leaving abrasive comments about your clips. All I got is admiration and thanks for you taking the time to do these videos and to educated people like me a bit. So thank you and carry on. Cheers. W
Blimey Liam, the dreaded AJ. I like the hi-bred roof myself or it has to go through planning to raise the roof. I am a general carpenter/joiner. As I have only done four of these garden rooms, I hang on to every word that you have said and It’s served me well many thanks.
Thank you for sharing this. I built my garden room with 90mm rafters to keep under the height limit and watching how you guys do the insulation has given me confidence to do the same in my build. I have first fix electrics coming this week so will be able to get insulation and membrane installed next week in time for the weather getting crap.
is your ceiling sagging if you used 90mm rafters? Using the span tables 90mm on 400 centres gets you a span of less than 2 meters? What are the dimensions of your room?
@@dugbert9 My ceiling rafters are C24 90x50 and are spanning a little over 2m wall to wall. They are certainly on closer than 400 centres and absolutely solid so far but that's to be expected as the roof was engineered and I just followed the diagrams I had been given.
Completely get it. Haters will hate. Ignore the trolls. You've said it enough now if they still talk shit then they obviously can't be bothered to look at your videos explaining why you do it that way. They just want to get a reaction. Plenty of us really appreciate you taking the time to upload your work
Totally agree mate as long as its low occupancy there will be no problems with condesation....its not like people are showering bathing or cooking in these rooms at most they sit in them and get drunk and watch tv ...well explained 👍🏼
As usual, makes sense to me. For all the haters, they could always add foil wrap into the squares you cut out the lights then seal to the surrounding insulation. If you foil tape where the lights come through the vapour barrier that would solve their moisture egress issue too?! Keep up the good work, loving the tutorials 👍👍👍
It might work for this level of building but it will defo condensate for two reasons, first you have cut the insulation in the zone for the lights therefore a difference in temperature especially over night. Also the joists are in direct contact with the cold and not isolated/insulated. Timber is no longer calculated at zero as they do conduct, even if only slightly. Therefore the ambient air zone is compromised and condensation will pool on the back of vapour barrier. It is important to provide people with rounded knowledge, but get this is only a garden room. I have built many passivehaus timber frame homes so have maybe more understanding than most in this area. Hope this input helps someone
I would agree - the vapour barrier is cut which will allow moisture to penetrate. I would have thought the ideal would be 70mm of insulation as he has tight to the OSB - ideally glue foamed to the OSB. Then a 50mm air gap, then 38mm of insulation backed plasterboard on the ceiling joists. Not sure the vapour barrier adds much in this case as you would be cutting through it anyway for multiple spots. The 50mm air gap could be vented both ends which is ideal. Thoughts? Yes you lose 26mm head height but worth it. On the floor, you don’t need an air gap if you have a membrane. So membrane, then 50mm insulation is sufficient, then ply, then your floor covering of choice. I just wanted to check before I do mine… so any reactions would be great.
@@glassdomedesign if you ventilate in-between the 70mm PIR and 38mm back plasterboard then the 70mm loses its insulation value. The 70mm would need to be to the lower side of the rafter against the 38mm and then to ventilate in the 50mm gap above.
Everyones an expert in the building industry!! And on that note, a better way of doing the hybrid roof system would be to wrap the moisture barrier round each joist void so it’s sandwiched between the insulation and the ply. Also that way you won’t need to cut a hole in it when you put your led lights in. 😂😂😂
Well done! You have described that perfectly. Anyone who is in the trade will understand you. People spend too much time looking at specs and varying ‘recommendations’ from Internet forums etc. Listen to the tradesman that do this day in day out and have years of experience not keyboard warriors. Great work chap. P.s don’t pander.
The one problem that hasn’t been highlighted is interstitial condensation. Using the hybrid solution shown in the video will move the dew point below the decking and even with a vapour barrier correctly installed sweating below the decking will occur. It is also worth noting that vapour barriers, even if installed correctly, are only effective below 60%RH. The guy is pretty knowledgable and his builds and videos are very helpful. However, this roof make up wouldn’t work and 50mm ventilation space would have to be incorporated to prevent future issues.
I’m not sure I agree. I’ve not found any tests performed that show sweating would occur. Cold roofs require a flow of ventilation and that is so often compromised, I would argue a hybrid roof will perform better. Either way, it comes down to attention to detail more than the choice of warm or cold
I think you are both right! There will be condensation, but, it is pressure treated lumber and it will eventually drip or evaporate away. If you look at what they do in America, it is very similar to this and they build everything out of wood. On another note, you could leave that 20mm ventilation over the cellotex or put 70 or 80mm insulation. The amount if insulation required now is just ridiculous! The difference between a U-value of 0.22 (100mm PIR) and 0.32 (70mm PIR) is 37W for a 20m2 roof with 20 degrees temperature difference. A human existing / resting produces 100w of heat.
Aye, ignore the haters. I really appreciate that you've gone the extra mile at least three times now, explaining how you do the roof, and why. Keep the vids coming, you're doing great stuff.
Glad to hear you tell folks about the 2.5m permitted dev taken from the highest point on top of slope. Makes sense when building on a slope. Finally got out of the ground tonight so base joists & hangers tomorrow! Great update bud
Cut into the slope and get more height to play with. I've got a 400mm fall where I'm planning to build so as understand it I can drop my base level and still measure the 2.5 from the heighest original ground level, so getting more like 2.9m.
@@jmccoy555 - If you do dig down, put some measures in place to cope with the 1 freak day of heavy rain in a 1000 days - the last thing you want is to get them floor joists soaked or even worse end up sitting in mud after a few years... Also - I recon a pinickety inspector would take the level at which you have dug down to build upon to be the ground level from which they will measure.. I would only cut in if you are doing so to reduce the extent of which the lowest ground level threaded bars are protruding from the ground level... The head height in Liam's builds is fine, why push it to gain a few cm and run the risk of being forced to pull it down after a few weeks, months or years...
@@TheStumpy3496 it slopes 3 ways, 400mm across the diagonal and 200/300 on the corners and continues to fall in all directions so no chance of a mud bath. Got to drop something or the front door will be in the air!! The regs quite clearly say its all measured from original ground level. It's actually quite a well documented loophole. www.google.co.uk/url?sa=t&source=web&rct=j&url=publicaccess.wokingham.gov.uk/AniteIM.WebSearch/(S(lkgvbv45pljxp545tp4dim45))/Download.aspx%3FID%3D92803&ved=2ahUKEwiioeTngeLrAhUDiFwKHbUhDUUQFjAPegQICBAB&usg=AOvVaw23YIP0ATx5nNXr52iGuNpK
Well explained mate,always informative and you clearly know what you’re doing. I’m looking at building a woodworking workshop in my garden to replace my old garage,and looking at 30 square meters floor space and using every available and legal height dimensions I can,but I’m lead to believe I’ve got to have the new build at least 2 meters from from a boundary,it’s doable but leaves a load of empty space around it. Do you provide a design service? I’m based in north Manchester . Keep up the great videos,onwards and upwards.👍
🏆 Happy to hear it explained so plainly and couldn't agree more on other people's designs which seem to magically come under 2.5m despite 8x2s rafters! I've been going mad trying to work out my heights but this certainly helps knowing I can do away with the cold roof ventilation gap and so get my services in easily. Do you ever have roof lights/sky lights in your buildings and anything to be aware of? I would love to have one on my little 3x3.5m studio but feel like there will just be issues with moisture, perhaps as there will be little space between cold rooftop and warm air near the glazing where the trimmers will be
Great explanation, I bet 90% of people that moan about your roofs have never even layed one,I done a flatroof on the main scientology building in East grinstead and that was a hybridu because it was south facing they speced the roof with 8 inch of insulation above deck but with that amount we would be upto the gutter on the adjoining roof, So I put to them 4 inches above and 4 inches in between and that's what we went for, It also cut the fixing bill by about 70%,you do a great job your a bit swift for me but I love watching your vids
excellent videos thank you i may or may not have made a mistake in my floor design, time will tell i guess i used a steel base from uroof ltd bonded with ct1 and screwed galvanised steel seets to the bottom and sealed all holes and sat the whole thing on ground screws, bolted and screwed each section together filled with recycled plastic insulation, then run 25mm steel box box sections along the floor panels at 400ish centres in the opposite direction to steel floor joins, 25mm pir between, covered in joint tape, then a dpm over the lot and wrapped down over the outside of the steel , then 18mm ply for the floor
Hands down...if I could afford one this is the only guy I would trust to build a garden building for me!! And as I can’t afford you I’m taking every tip I can from the channel and building my own!lol😊👍🏼 really appreciate you taking the time to show us how it’s done properly mate
If you use foil back plasterboard and seal the back edge of the joints with Cilicone they act as a vapour barrier, that’s how I do mine. I also do my roof to your method since seeing your videos and it works great. I’ve never looked back. 👍
What your doing is really smart to stay within the hight limits personally I wouldn't bother with the vapor barrier on the inside if your gona cut holes in it for sockets downlights etc . Iv built a few houses and used blower prof on the outside osb and tape the joint s Fewer penatations . Your garden room s look great
You’re spot on bud, any thoughts on me insulting on the outside of my shed for the winter? My shed walls are 22m thick. So I don’t lose internal space I’m looking to run a layer of roofing breather on the outside, then a couple of layers of foiled bubble wrap, then a match cladding onto vertical roofing batterns. 1 do you think it’d work (I’m damp sealing the floor internally btw)? 2 do you think it’d reduce condensation in my shed? 3 do you think it’d keep the shed warmer? As it’s my new office. Keep up the good work btw. Cheers Ed
Bloody great video. Even numpties like me can follow it. Just doing this in my roof of my garden room at the moment. Can I assume it is the same principle for the walls? I've got cladding, then breather. So the insulation board would sit up against these two layers. Cheers from Sunny Devon!
Hi William, Great video once again. Please could you advise what you would do for the roof if you were putting a hot tub in there with half height walls on the front and sides? I am not planning to plaster or anything and wondering what to use for the ceiling? Regards, Simon
Just discovered your channel & couldn't subcribe fast enough! What a well built room! Wish we built this way in Australia. Interested in a working holiday?
I came across this video as I'm researching how to deal with unvented cold roof. I'm building a summerhouse and am up against the height limit as you describe. I'm of the same view as you; low occupancy and in my case, as one wall will be a bifold door and probably open when occupied, there will be very little warm moist air in the room anyway. Most of the advice on domestic construction is aimed at occupied dwellings and designers have to work on worst case of family taking lots of showers, cooking, drying clothing so high moisture levels. I've also come across research from Germany that backs up the cold roof but with no cold air void (as your build) although this requires attention to detail and ensuring no air can flow form inside through the roof deck. The German research also criticises the assumption that air flow in a vented gap will actually remove the trapped water; if there's insufficient air flow then all you've left is an uninsulated air void for cold moist air to condense on the timber. In my case I'll be fully packing the void, VCL and also using a spray applied sealant on the underside of roof deck at any possible air gaps. German research also recommends using a smart VCL (which can change permeability and allow any moisture trapped in the roof to vent down into the space in correct conditions) but it cost more than a standard VCL so I'm not using it but I am installing a MVHR with humidistat to deal with the odd occasion when the room may be used with doors closed and a few persons in it. I'm a professional in the construction industry (Site Engineer with Construction Degree and over 25 years of experience) and yes, a warm roof would always be a best option but sometimes it not possible. My thought are if the roof structure has no air leaks then how can moisture vapour (which can only be airborne) get into the cold roof space in the first place?
Hi Andrew Not sure if you have seen a later video where I talk about the report a viewer did on the hybrid roof we do. It states that there is no risk of mould build up snd any moisture that does occur will dissipate in the summer months. It concludes the hybrid roof we do will not fail under the conditions we install 👌
Hi Liam, I fully agree the hybrid roof in this use case is the best option. I think councils should be updating the planning restrictions of 2.5m. If they increased this even to 2.65, it would allow for a warm roof. This would be environmentally friendly as it would reduce long term roof replacements, although in the sort term I can see it having a negative environmental effect due to the increased materials required, but does seem that 2.5m is an arbitrary value with little consideration as to it's impact on the design of a building.
Thanks for the videos...they're really useful. Very clear. Now, I get that the air below the insulation is ambient temp so no condensation, which makes me wonder.. do you really need a moisture barrier? (Especially in a low occupancy room eg home office) I'm not saying you don't. I'm just wondering why.
Great vid, Is this is why you can successfully frame and spray foam a shipping container with air gap on inside at ambient temp, then moisture barrier and ply or Osb with no sweating issues?
Hi William ... All cold deck info tends to be based around habitable areas. Thanks for clarifying the use of cold deck for garden rooms and confirming what my father in law constantly says about limited condensation risk. Can I ask about heating and with an under insulated raft slab, would you suggest underfloor electric heating or convectors or both? ... Used for office working 5 days a week, size is 12m2 with bifold doors
Hi, I’ve watched most of your videos and I love how sometimes your quite blunt with regards to what other people say lol. I’m having a Apex timber shed delivered and I’m going to have electrics installed, then insulate and ply board the walls and with regards to the roof, i am going to do what you have done regarding not leaving the air gap by the outside wall on the roof, but was just wondering, do you do the same for the walls? Or should an air gap be left nearest the outside wall. Thanks in advance for your reply.
Typical keyboard warriors. Its normally jealousy that triggers them! You do a great job mate. Love the vids, very informative and thanks for sharing. I will be finishing my base today. Pile's are in and frame work almost done then onto insulation, mebrane and 22mm floor. Thanks Liam...👍
Great video, could i use Rockwool type batts instead of the rigid boards you have used. I understand they will be lower insulation values but Im thinking from the condensation point of view cheers
Great advice as always. To anyone with half a brain you know your sh*t, so f*ck the trolls mate, stop mentioning them at all, they feed on mentions, starve them out. You're smashing this RU-vid thing 💪🏻
Hi mate love the videos very informative. I just had a question. I'm a novice so hope it is not silly, my outbuilding is 4mx3m do the same building regs apply?
Makes me laugh when people state its OK to go over no one will notice . Really try and sell the property and wait to you get a survey done. Love your builds and my kitchen extension is a hybrid roof . Was fully passed by inspection and its also a flat roof this gave us more head room as advised when designed due to pitch would loose head height . Some people claim to know it all but haven't got a scooby doo .. great vids keep em coming.
Exactly, hybrid roofs work, you’ve gotta stick to the rules, on one of our current jobs the council are coming out to measure, her words to me” if your sure your under 2.5, your safe!” 🤣
Thanks for all your straight-talking videos - you’re helping loads of us DIYers. Ignore the trolls - you’re doing great. What vapour barrier do you use for hybrid roof pls?
Would you still do the hybrid roof if you was fitting any sort of heating. Keep up the good work, i stumbled across your channel when i was looking at how to build the timber building at the bottom of my garden. You've been very useful. Thank you. Haters going to hate.
I love your vids mate. Gonna build my summer house next year and will be using your vids to help. Definitely gonna finish in cedar, they look the nuts. Have you ever done one on a base of bricks? I only ask as I have a solid concrete slab at the bottom of my garden that I’m building off and I thought of doing it that way to stop water settling on the slab.
If your happy with the strength of the slab , build off it mate, two choices, overhang your structure so no water gets on the pad Or sit your build off it, sit it on dpc and galvanized uni strut
william griffin thanks for the reply mate. Didn’t think of Uni, I can get a ton of it from work. I’ll look in to that. Keep the vids coming, quality stuff. 👌
If the insulation is 1mm out then there is a condensation hence black spots that's why the bigger the air gap above the insulation the less chance of air settling 🔨
The biggest issue I have is the fitting of down lights introduces holes in the construction with very little insulation above them. I'm not qualified and not in the trade. Built my own warm roof and sacrificed a couple of inches headroom.
Thanks for demonstrating this and your excellent videos - they have helped with my build! I am going to use this approach but use the 20mm space above the insulation instead. There would then be a further added benefit if this slim area could be ventilated... right?
This roof is fine because the due point is going to be located in the middle of the 100mm insulation where there is no room around it for air to condense, there theoretically could be a tiny amount of condensation around the due point location in the insulation if it isn't cut tight, but hardly worth worrying about. A better solution might be to fill the cavity completely with spray foam insulation which would completely remove the possibility of humid air buildup.
Don't worry William as there are haters everywhere but professionals like you are not so easy to find.People should take a leaf out of your book and get on the tools to see how easy it is (or is not) . I spent 14 years in the wines and spirits industry and was forced out of my job due to Covid. DIY was my passion so i have picked the tools and put them to work.There are jobs are out there if people can be bothered to work instead of trolling those who do...keep up the good work!!!!
Nick, I see you often in the comments, thank you for your support and always your advice and kind words, it’s friends, and I say friends, because of see you all as friends, tgat I keep posting 🙌
Nick Demetriades just read back my English 🤦🏻♂️seriously, I’ve built a community and following from nothing in a small period of time. I’ve a passion for what I do, I thought I was alone. Then you guys appeared! I’m blown away, I’ll hit 20k subs next month, channel 4 and 5, have emailed me. It’s amazing and quite frankly I’m still in awe!! If you ever need anything answering just ask and if I don’t reply, call me 💪thank you, and any of you reading this that folllow me xxx
@@thegardenroomguru Don't worry about the English mate..cant believe that you have so many followers and yet you can tell from the quality of info its a no brainerAbsolutely no surprise about C4&5 wish you all the best with that and i know you will smash it
