Air tightness New Build. Wooden frame

clauduledus

Hi All,

I am building a house at the moment and the electricians have been in to do the first fix.

I think this is a simple enough question, although the answer may not be.

The electricians, obviously had to go into attic space and out into the garden/exterior walls for lights, cables etc. How do i seal these cables air tight. I will have to use an expandable foam/silicon method as the holes are not the neatest. My builders are very happy with the foam they use, and I dont doubt them. I worry that the seals wont be good enough and the air tightness test will show it up.

Has anyone had any other experience / methods of sealing?? Any help would be great. Think they are slabbing walls in the next day or 2. Cheers in advance

delfagio

Trim back any of the expanding foam used to seal the hole in the timber frame wall so that it's flush with the frame, then use airtight tape over it all and around the point where the cables come through.

clauduledus

I was thinking about that sort of technique. I was also search online for a sort of heat shrink wrapping used in packaging but your method sounds easier and safer. Many thanks.

Gumbo

You should use penetration slivers that wrap around the wires and fold into the existing air tight membrane. You then seal with tape. Similar to how you sealed around rising drainage pipes coming through the radon barrier.

hesker

pro clima do a product called Kaflex which is basically just some EPDM integrated with air sealant tape. I’ve used it and it seals nicely around cables but you might be a bit limited on sizes.

delfagio

By the sounds of the original poster clauduledus the cables are already installed. A lot of these products mentioned are specifically designed to be installed when the cables or pipes are been installed. i.e. when installing the cable you pull the cable through the these slivers or top hats etc. Not the case in this circumstance as the cables are fully installed.

Easiest and cheapest way is to just use airtight tape and tape over it all and around the cables.

I done this on my new build and we achieved an airtightness of 0.29m3/hr. Just make sure you spend the time to deal it all properly

BryanF

clauduledus wrote: »

I was thinking about that sort of technique. I was also search online for a sort of heat shrink wrapping used in packaging but your method sounds easier and safer. Many thanks.

If your builders are using foam to make a timber frame build air-tight, they are cowboys.

What is your design/contract required air-tightness rating? If you don’t have this you arch/eng are not doing their job.

I’m mid air-tightness on my own timber frame - rolls and Rolls of tescon , contega and lots of intello , I’ve tried other products - not impressed in comparison to pro clima.

MicktheMan

BryanF wrote: »

If your builders are using foam to make a timber frame build air-tight, they are cowboys.

^^^^^^^This

bertie 56

If the wires are already in place, that is a mess ...
You have some airtight " silicone " that could be used, if the holes are not too big .
Ex : Siga Primur does the job for this .