Battening out sloped ceilings for PB

[dpmiller]

So I need to batten over our inner insulation layer on the slopes. External walls are already done as part of the TF contract. The ceilings won't be battened, we're using 1/2"TE, and all studwork and the roof are at 400ctrs.

Do I need to batten horizontally top and bottom? If so i guess we'd be about 100mm in from the insulation edge to screw firnly through, yes? Or at 400ctrs is battening on the rafters enough?

 

ta.

[Onoff]

I'd first cut a fillet of pir to go along the top and infill (or gun foam) where the sloping board meets the ceiling. I can see a gap! ?

 

I'd do horizontal battens top and bottom then at 400 ctrs on the rafters. You want to support where the slope end's boards meet the wall & ceiling and back up the joint tape/scrim. Even then you might be wanting a flexible filler later on if you get any cracks. 

[PeterW]

So... I would just use cut a piece of 25mm thick insulation(or the depth of your battens)  about 6” wide and just fit between the battens at the top and bottoms of each gap. Quick and simple and will take the spring out of the corner joints. 

[dpmiller]

that sounds useful @PeterW . I didn't think 1/2" at 400mms  would want to move too much. @Onoff I'll be filleting the larger gaps but would worry about foam tearing the AT membrane over time as it moves around in the wind. The metallised layer is the AT, and I've noticed that the Sicrall is sticky enough to delaminate the membrane...

[nod]

I’d normally board the wall and ceiling first Then use 75 x 25 batons horizontal Butted up tight against the ceiling and wall This way will help  you  make accurate cuts on your slope Always put the uncut edge of the Pb to the top This will give who ever skims it a clean line to skim down to As there is always a bit of undulation on the trusses