MikeSharp01

Yes there is a reasobable explaination of this here http://www.greenspec.co.uk/building-design/thermal-mass/

Yes it should say VCL really - it was a thread yesterday that prompted me to check as I was merrily working away on the principle that the housewrap was on the outside I agree I think the architect got it wrong for some reason. I will drop him a note to check his thinking but it is on every section drawing in this form so his cad package, Archicad, just linked it through everywhere. No but there is a reason the PU is on the outside of the sheathing so as to ensure the cold bridges of the I Joists and the ends of things like (only) the ridge beams have insulation beyond them. You are right it seems a bit daft to have the permeability the wrong way around but I surmised that as long as the VCL is less permeable than the PU (Even though it is foil backed) and I don't foam the PU edges tight the water vapour will pass out of the structure.

Way back in 2016, during our design exercise, which you all helped with here: I thought the build up of the wall (inner to outer) was: 12.5mm Platerboard 35mm service void. Air tight barrier. 300mm I Joists filled with DRITHERM .032 insulation 12mm OSB (4) 40mm Kingspan K12 Tyvek UV breather membrain 25mm Verticle battens (Ventilated) 25mm Horizontal battens (Ventilated) Marley Internit Thrutone cement tiles. However I have now double checked the architects drawings, and those submitted to BC and the build up is now: 12.5mm Platerboard 35mm service void. Air tight barrier. 300mm I Joists filled with DRITHERM .032 insulation 12mm OSB (4) Tyvek UV breather membrain 40mm Kingspan K12 25mm Verticle battens (Ventilated) 25mm Horizontal battens (Ventilated) Marley Internit Thrutone cement tiles. You can see that the Breather and KingSpan have swapped places. Simple question, does this make any sense putting the breathe membrane before the PU Kingspan, which is foil faced, as I don't get how the vapour can get out of the breather if it is covered by foil faced PU, or am I worrying about nothing?

We used this on the Garden room part of our build in Whitstable, easy to use and relatively cheap (£70 per roll +VAT). Following your prod @Constantine I will revisit our wall / roof build up as I have noticed that the breather (not the VCL) is after, on the way from inside to out, the main insulation but before the metalised PU.

Be a bit careful, we went through this in our design and are about to go through it on our build. Using vapour barriers as the air tight layer - EG sheets of polythene is a risky option as it does not allow any vapour to pass through thus making it more likely that moisture can build up in the wall fabric. Hence your architect has specified a VCL as the air tight layer on the inside of the walls. Naturally on the outside you will have a breather membrane as a secondary water protection layer behind the tiles / cladding. As I understand it, others are more knowledgeable, the breather must be more permeable to moisture than the VCL so as to drive moisture out but it must be possible, when the conditions are right, for vapour to pass through the VCL back into the building - usually in the summer.

No, in our case we have 250mm (2x100mm = 1x50mm) this was because the slab designer was worried about some of loads in the middle of the slab and after they did the sums they chose 250 rather than pockets down to 100 in all places where the loads were.

It was basically loose in the lorry but packed tight. Three of us hand balled it off as packs of 5x100x2400x1200 EPS or 10x50mm and then the edge pieces one at a time all of which weight nothing and could be carried by a child privided they could get a grip of the packs / pieces. It took about 20 minutes. I piled it all up and then sheeted it over and tied it down as the one thing it does really well is blow away at the slightest breeze if left unrestrained and it does get attacked by UV if left exposed for an extended period.

Our system was not from Kore but very similar. Our slab is 100m2 and it was 3/4 of a cirtain sider artic but weighs nothing except the outer sections with, in our case, the render on.

I am not sure TF is more expensive than brick and block once you do a fuller cost accounting exercise and its all timber rather than brick skinned timber frame.

drill a new hole straight up?

Thats good for us as it could be used to stop our neighbors overshadowing our solar where they ever to go for two stories.

Thanks Jeremy. That is good to know. We are not sure we are going for Warmcell quite yet but knowing we need take no special measures is a comfort!

anybody know if you can blow cellulose direct against the air tight membrane? Our walls are 300mm I joists with 15mm OSB on the outside and the air tight membrane on the inside.

Sorry if I missed it, do you have the link? I think I could make the glass demountable and still seal it.

We are getting along now with the frame and we have noticed that we have a couple of windows that are fixed, IE don't open, but where the frame dimensions are significant in terms of the frame/glass ratio. This impacts the Uw value and somewhat reduces the light, It struck me that the frames are the structure around the glass, I have to provide suppert for the frame within the structure, the frames are worse U values than the glass and I could use the building as the frame as I could build and seal a 3G glass unit into the wall structure without a frame and get more light into the aperture. I have not done any detailed work on this but thought I would put the idea out there for comment. Anybody tried such an approach?

Yep 1 Wh = 1mkWh then strange this powers of 10 stuff... wonder what a nano gWhr is. ?

Is that 1mkWh then, one wonders? Never heard it used as a unit but I guess it must be.

Opposable Thumbs? (Yes I know some other animals have them)

Take one off and measure it?

I will be doing a load more tomorrow so I will keep an eye on it.

Those two in the pic happened one after another but the 25 below and 33 above are fine.

No they are going through 15mm OSB and into the ply flanges of FinJoist I beams. It seems to miss about 1 in 30 on average.

It has only done about a 1000 nails - so no. Its as if it hits a sudden hard spot.

Sorry - driving home, Cordless

I have been nailing away on our frame today ans occassionaly I get what looks like a miss fire but they knock in with a hammer ok. I thought it might be bounce but it seems not to be as it happens on realy solid parts. Any ideas? PS Gun is a Dewalt electric framing nailer and the nails are 50mm long.