Air tightness advice needed on a dormer bungalow new build

[Olly P]

Hi 

We are currently building the roof structure on our 430sqm dormer bungalow. We have gone with 150mm cavity to allow for 100mm pir insulation and have took our time taping the insulation together when installing. I am wanting to make the house as air tight as reasonably possible and I'm going to install MVHR. I'm just wondering how the correct way would be to seal the roof and insulation between the rafters to the wall plate? And without parge coating the inner walls, apart from making sure the pointing of the blockwork is good, what else can I do to help this? 

 

[nod]

1 hour ago, Olly P said:

Hi 

We are currently building the roof structure on our 430sqm dormer bungalow. We have gone with 150mm cavity to allow for 100mm pir insulation and have took our time taping the insulation together when installing. I am wanting to make the house as air tight as reasonably possible and I'm going to install MVHR. I'm just wondering how the correct way would be to seal the roof and insulation between the rafters to the wall plate? And without parge coating the inner walls, apart from making sure the pointing of the blockwork is good, what else can I do to help this? 

 

We have recently sealed some lifts before putting a ceiling in below 

Hears a couple of pictures 

We put a band of acoustic sealer around the perimeter and trapped the membrane with 35 mil angle shot fired to the peeling and block work 

[Chablais]

Hi we just re roofed our entire house, converted to a warm roof, used 120mm PIR on top of the rafters, then 125mm mineral wool between, at the eaves we joined the cavity insulation to the rafter infill. Our airtight layer is on the inside of the rafters, we used Tyvek Airguard, taped to the inside walls. Most of rooms are up to the roof slope. It was fiddly in places but hopefully worthwhile. You need to invest in the correct tapes. If using a warm roof design, then think about windproofing it by sealing the roof membrane at all laps, and also tape it to the eaves protectors. Loads of good info on the Tyvek website