depth of insulation for an attic conversion

blueskys · 29-08-2017 11:02PM #1

Hi all
Am currently putting in 180mm of metac isover between the roof rafters while converting the attic and will put 12m drywall on the outside.Am debating about putting in counter battens and 50mm of insulation on top of the insulation though. What is the recommended depth/ ye would normally go with here? cheers

BryanF · 30-08-2017 07:56AM

Have you removed slate/tiles externally? Assuming you haven't, have you install vents? And left 50mm min gap between felt & insulation.

Have you installed an air-tightness membrane tapped and sealed to wall plate/lower ceiling? Even better if you could strip lower few slates/tiles for access to do this work.

blueskys · 30-08-2017 10:15AM

BryanF wrote: »

Have you removed slate/tiles externally? Assuming you haven't, have you install vents? And left 50mm min gap between felt & insulation.

Have you installed an air-tightness membrane tapped and sealed to wall plate/lower ceiling? Even better if you could strip lower few slates/tiles for access to do this work.

Hi havent removed tiles. yes vents are in, theres a 45mm gap between felt and insulation. just wondering if the insulation is thick enough really before i put the air tight membrane on the inside. cheers

BryanF · 30-08-2017 12:06PM

Honestly if the air-tightness and ventilation aren't right More insulation is not the solution

I would install AT membrane taped and sealed and then batten with 50mm/insulate/plasterboard

depth of insulation for an attic conversion

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