Air Tightness between ground and first floor

[Drew1000]

Hi,

 

I am about to erect a timber frame and the kit company have said they do not supply the membrane that I used on my last timber frame between te downstairs panels and first floor panels.  It sits on top of the ground floor panels and laps up the outside covering the perimeter joists before lapping back inside on the upper floor where the first floor panels sit on top of it.  It is then taped to the VCL both downstairs and upstairs to maintain air tight integrity.  My last kit company supplied it but I am having difficulty establishing the correct material to use for this part of the build.  Any help much appreciated on make or manufacturers/suppliers or what I should be ordering. 

[dpmiller]

our build just used heavy polythene

[ProDave]

The detail you are talking about is sometimes referred to on here as a "Tony Tray"

 

If the builders won't supply the membrane go and buy a roll. It is FAR easier to install it as the frame goes up, than try sealing around the joists afterwards.

 

I believe the best membrane in Intello, but that is expensive. A cheaper one is Protect Bariair.

[Drew1000]

Thanks for advice guys.  Used FCM 750 as that is what I was looking for but could not remember the name.  Regards