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Post by thatsnotafestool on Nov 4, 2007 18:13:31 GMT
Seeing as how it looks like building control are going to insist on me sticking 65mm of foam insulation across my rafters, I'm struggling to see how to fix the plasterboard as the longest Senco drywall screws I can find are only 50mm.
Or how else can I quickly/easily/cheaply fix the plasterboard up?
Thanks
Roger
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Post by engineerone on Nov 4, 2007 18:42:28 GMT
what about gripfil and nails to hold on until it is sets??? paul  |
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Post by jfc on Nov 4, 2007 19:04:22 GMT
Cross battern the rafters and fix to them .
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Post by thatsnotafestool on Nov 4, 2007 21:27:44 GMT
Cross battern the rafters and fix to them . There won't be any room left in my room if I do that  |
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Post by Scrit on Nov 5, 2007 5:43:33 GMT
I know that the Senco guns will drive 65mm decking screws I'm just surpriosed that Senco don't offer collated drywalls at that length. Perhaps one of the independent fastener firms might be able to help. Other than that it's loose screws and a cordless.....
Scrit
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Post by jfc on Nov 5, 2007 17:45:14 GMT
Your putting 65mm insulation on the rafters anyway so putting 65mm batterns across and insulating between them wont take up any more room than the insulation .
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Post by thatsnotafestool on Nov 7, 2007 18:52:40 GMT
There's insulation between the rafters...65mm thick. That is flush with the underside of the rafters. If I have to apply another 65mm to go over the top of that lot - to eliminate the thermal bridging of the rafters - then put cross battens on top of that to take the plasterboard..well, won't that increase the depth?
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Post by jfc on Nov 7, 2007 19:21:31 GMT
No i was saying lay your insulation between the 65mm cross batterns but i didnt reralise you had to do this because the rafters where a problem in the first place . I've never heard of that before , normally you cross battern and insulate between that to form an air gap . Your saying they want 130mm of kingspan or the like ?
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Post by thatsnotafestool on Nov 7, 2007 22:19:20 GMT
Yup...for pitched roofs, that seems to be the norm as far as i can make out.
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Post by jfc on Nov 7, 2007 23:03:59 GMT
No the norm is 50mm air gap and what ever insulation the local council want between the rafters . So the norm would be cross battern and insulate between 50mm batterns leaving the rafters as the air gap . Have you been told this by the BI or seen it on the net ? Sounds to me like you are looking at a warm roof (for flat roofs) Where the insulation is on the outside .
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Post by thatsnotafestool on Nov 8, 2007 6:14:42 GMT
...and what ever insulation the local council want between the rafters . . Is that correct? Building Regs specify a u value for a pitched roof of 0.2. To achieve that you need somewhere between 100mm and 130mm depending on type of Kingspan and Rafter spacing. I don't think that the BI has that much leeway?? |
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Post by jfc on Nov 8, 2007 7:34:40 GMT
I take my regs from what ever council i am working with at the time as they are the ones comming out to check it . My warm roof on the kitchen is 75mm ( flat roof ) and a loft conversion down the road i did was 50mm (pitched)
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Post by houtslager on Nov 11, 2007 8:46:16 GMT
Surely, if you put foam above head height, then you will need to put a double layer of plasterboard to reduce fire risk as melting foam is very very dangerous!
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Post by thatsnotafestool on Nov 11, 2007 14:49:23 GMT
Ah well..we shall see. The Building Inspector is coming tomorrow.....
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Post by jfc on Nov 11, 2007 15:58:42 GMT
Dont be silly Houts this is GB . A condition of my mortgage was to remove all foam tiles from my ceilings . Then when i extended the kitchen i had to have a foam warm roof and put foam under the floors  Edit , oh and lots of plastic |
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Post by thatsnotafestool on Nov 12, 2007 21:21:14 GMT
The Building Inspector came.
I can either put another layer of 65mm Kingspan under the rafters to eliminate the thermal bridging due to the rafters and meet their requirement for ...well, he wasn't really sure just how many mm of insulation they needed. So we settled for 65mm in between the rafters and the 65mm just mentioned.
Or...I can put a layer of TriOso multifoil under the rafters. Which is what I was going to do....until I checked out installation. This stuff MUST have an air gap on both sides of at least 25mm. So that means 50mm depth. Kingspan (I buy seconds) is 65mm and so the saving in depth if I go the TriOso route is 15mm -
T'aint worth it. It would make sense if Building Control accepted the u-values given by the TriOso manufacturers....in which case I'd not need the Kingspan in between the rafters and so that would automatically give me one of my airgaps at no cost to decreased room dimensions. Bit of a bummer.
Oh yea...he liked my internal oak beam work ;D
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