matthyde83 Posted May 24, 2022 Share Posted May 24, 2022 I've been taking a look at ACTIS insulation. When searching the forum I can see various comments about its lack of performance as a foil but how about if using the full build up? In a warm roof construction from what I can see if you select all three products it can deliver 0.1 U Value in 200mm depth. Thoughts?? Link to comment Share on other sites More sharing options...
JohnMo Posted May 24, 2022 Share Posted May 24, 2022 But does that include all the air spaces you have add between each layer? Most of these systems when you take into account full build up depth, do not give any improvement on a basic glass wool. I think we would all like to get great levels of u value without thickness, but it's not realistic. Link to comment Share on other sites More sharing options...
matthyde83 Posted May 24, 2022 Author Share Posted May 24, 2022 Link to comment Share on other sites More sharing options...
SteamyTea Posted May 24, 2022 Share Posted May 24, 2022 If it was as good, for the overall thickness, then everyone would be using it. Link to comment Share on other sites More sharing options...
matthyde83 Posted May 24, 2022 Author Share Posted May 24, 2022 43 minutes ago, SteamyTea said: If it was as good, for the overall thickness, then everyone would be using it. Kinda what I was thinking - so the general opinion is that it isn't then?!!! Carpenter that is pitching the roof recommended it. Link to comment Share on other sites More sharing options...
JohnMo Posted May 24, 2022 Share Posted May 24, 2022 (edited) Just been on the site and the simulation tools. To get a u value of 0.1 you need HCONTROL HYBRID 45mm HYBRIS 210mm thickness BOOST'R HYBRID 35mm So even without any air gaps you are at 290mm, without the air gaps you get no where near 0.1 So even their simulation says it's not possible. Edited May 24, 2022 by JohnMo Changed with to without Link to comment Share on other sites More sharing options...
matthyde83 Posted May 24, 2022 Author Share Posted May 24, 2022 Sorry - I need 0.16 to be achieved with planned 200mm of celotex. Just looking at options. Celotex isn't exactly cheap atm! Link to comment Share on other sites More sharing options...
JohnMo Posted May 24, 2022 Share Posted May 24, 2022 How deep are your rafters and how much room below do you have? Link to comment Share on other sites More sharing options...
matthyde83 Posted May 24, 2022 Author Share Posted May 24, 2022 8 minutes ago, JohnMo said: How deep are your rafters and how much room below do you have? Current spec 50x150 @ 400 centres (which doesn't allow for 200mm pir!) Link to comment Share on other sites More sharing options...
LA3222 Posted May 24, 2022 Share Posted May 24, 2022 2 hours ago, matthyde83 said: How the hell.do you get a sealed air cavity when you have all those rafters to work around. Snake Oil. Link to comment Share on other sites More sharing options...
Buzz Posted May 24, 2022 Share Posted May 24, 2022 27 minutes ago, matthyde83 said: Current spec 50x150 @ 400 centres (which doesn't allow for 200mm Is there any reason you can't put 50mm under the rafters to get you to 200mm Link to comment Share on other sites More sharing options...
matthyde83 Posted May 24, 2022 Author Share Posted May 24, 2022 1 hour ago, Buzz said: Is there any reason you can't put 50mm under the rafters to get you to 200mm Nope, I can do. Investigating ways of achieving 0.16 (or better) for less £ Link to comment Share on other sites More sharing options...
JohnMo Posted May 24, 2022 Share Posted May 24, 2022 I would have a good read in the heat insulation section, will be examples in there Link to comment Share on other sites More sharing options...
Buzz Posted May 24, 2022 Share Posted May 24, 2022 19 minutes ago, matthyde83 said: Nope, I can do. Investigating ways of achieving 0.16 (or better) for less £ Counter batton your tiles Full fill rafters with multi roll and put 100mm pir under Link to comment Share on other sites More sharing options...
NSS Posted May 24, 2022 Share Posted May 24, 2022 You know what, I just can't be bothered. 1 Link to comment Share on other sites More sharing options...
Iceverge Posted May 24, 2022 Share Posted May 24, 2022 (edited) Have you disregarded the above? Edited May 24, 2022 by Iceverge Link to comment Share on other sites More sharing options...
matthyde83 Posted May 25, 2022 Author Share Posted May 25, 2022 5 hours ago, Iceverge said: Have you disregarded the above? Nope absolutely not. It’s working with the builder and carpenter and weighing up their suggestions also that’s all. Clearly we’re not fond of actis so a no go there! I was going to send another note on the above. I’ve contacted warmcel to find a provider and the build up they are recommending is concerning me on a cost basis. Smart ply propassiv inside, medite outside. Going to cost a fortune in labour and materials?? Link to comment Share on other sites More sharing options...
Iceverge Posted May 27, 2022 Share Posted May 27, 2022 On 25/05/2022 at 06:00, matthyde83 said: Smart ply propassiv inside, medite outside. Going to cost a fortune in labour and materials?? Unless you need racking on both sides I don't think it's necessary. Your SE will know. As far as I know propassive and Medite are both structural racking boards and this type of build up is normally required with timber I joist or double stud walls that require racking on both sides. I don't think it'll be needed on a roof. Again, that's SE territory. For the cost you won't beat glass wool normally but this appears to be a good price for Rockwool (15/m2 inc VAT) which is nicer to work with, better for heat and sound protection. '' The build-up is 12.5mm plasterboard, 45mm battened service cavity with 50mm Rockwool. Vapour Barrier, 195mm rafters full fill with 2x100mm layers of rockwool. Breather membrane taped at all joints. ( it needs to be a suitable breather membrane for this, Tyvek Supro , Siga Majcoat, etc) Batten Counter batten. That will buy you a very cheap and very good roof. Is suspect one of the reasons your builder/carpenter like the idea of ACTIS is that is very easy to handle for them. Easy to cut and light to fit. Fitting insulation by hand is really a pain. Nobody likes it, however rockwool probably one of the best ones. Imagine the glee on their faces if you tell them about blown cellulose! For a 200mm rafter it's €27+VAT installed in Ireland about £22/m2. Again, I would consider 15mm plasterboard ( sound protection, service cavity battens at 600mm cc) Blown cellulose in a 220mm rafter. External OSB racking (durability, strength, sound, rodent protection. Here is a more official drawing from a company that makes nice houses near Dublin. If it helps you to convince anyone. 1 Link to comment Share on other sites More sharing options...
matthyde83 Posted May 30, 2022 Author Share Posted May 30, 2022 On 27/05/2022 at 11:40, Iceverge said: Unless you need racking on both sides I don't think it's necessary. Your SE will know. As far as I know propassive and Medite are both structural racking boards and this type of build up is normally required with timber I joist or double stud walls that require racking on both sides. I don't think it'll be needed on a roof. Again, that's SE territory. For the cost you won't beat glass wool normally but this appears to be a good price for Rockwool (15/m2 inc VAT) which is nicer to work with, better for heat and sound protection. '' The build-up is 12.5mm plasterboard, 45mm battened service cavity with 50mm Rockwool. Vapour Barrier, 195mm rafters full fill with 2x100mm layers of rockwool. Breather membrane taped at all joints. ( it needs to be a suitable breather membrane for this, Tyvek Supro , Siga Majcoat, etc) Batten Counter batten. That will buy you a very cheap and very good roof. Is suspect one of the reasons your builder/carpenter like the idea of ACTIS is that is very easy to handle for them. Easy to cut and light to fit. Fitting insulation by hand is really a pain. Nobody likes it, however rockwool probably one of the best ones. Imagine the glee on their faces if you tell them about blown cellulose! For a 200mm rafter it's €27+VAT installed in Ireland about £22/m2. Again, I would consider 15mm plasterboard ( sound protection, service cavity battens at 600mm cc) Blown cellulose in a 220mm rafter. External OSB racking (durability, strength, sound, rodent protection. Here is a more official drawing from a company that makes nice houses near Dublin. If it helps you to convince anyone. So a few challenges... My rafters are 150 @ 400 centres where I need 0.16 and 175 @ 400 centres where I actually need 0.11 (according to SAP calculation - which I could always go back to?) The slabs are still quite a bit more expensive than roll... I can get 300mm of roll for about £8 per metre. It's just supporting it. So one idea was OSB on the inside then can simply roll out on top? Link to comment Share on other sites More sharing options...
Dave Jones Posted May 30, 2022 Share Posted May 30, 2022 On 24/05/2022 at 20:33, matthyde83 said: Current spec 50x150 @ 400 centres (which doesn't allow for 200mm pir!) you dont want 400 centres as you will have loads of waste, you want 400 gaps to get 3 rips out of a sheet with zero waste. Link to comment Share on other sites More sharing options...
Iceverge Posted May 30, 2022 Share Posted May 30, 2022 5 hours ago, matthyde83 said: My rafters are 150 @ 400 centre Has the roof been built? Link to comment Share on other sites More sharing options...
AccidentalSkydiver Posted May 30, 2022 Share Posted May 30, 2022 5 hours ago, Dave Jones said: you dont want 400 centres as you will have loads of waste, you want 400 gaps to get 3 rips out of a sheet with zero waste. agreed... 500mm OC with a 47x225 would give you about 455mm(ish) gap in the middle, which would allow for a roll or standard batt to fit easily. 600 centers, you could rip a cellotex 2440 x 1220 in half, throw on some gapo tape on the edges and seal that cavity shut... Link to comment Share on other sites More sharing options...
matthyde83 Posted May 30, 2022 Author Share Posted May 30, 2022 46 minutes ago, Iceverge said: Has the roof been built? No not yet. We're about 4 weeks from starting it. Link to comment Share on other sites More sharing options...
Iceverge Posted May 30, 2022 Share Posted May 30, 2022 Just change the spec then to what you what. Link to comment Share on other sites More sharing options...
matthyde83 Posted May 30, 2022 Author Share Posted May 30, 2022 3 hours ago, Iceverge said: Just change the spec then to what you what. I’m trying to work out what I want. Ha. As anyone I suppose, I want a good but inexpensive solution. Mutually exclusive probably. My SE is almost impossible to get a response from so anything requiring his input is out really. So standard timber, either as drawn or deeper? I’m trying to find a better solution than drawn with 200mm PIR on vaulted and 400mm rockwool in the loft elsewhere. Or is it just easier to leave it at that? My thoughts were to take the airtight layer into the loft. I’m hoping to have hot water cylinder and MVHR unit up there. Link to comment Share on other sites More sharing options...
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