loss of airtightness thro the floor slab

SRV

Hi,

I read somewhere that there could be an issue of airtightness being compromised due to leakage thro the floor slab. Can expansion cracks in the slab lead to this?

My slab will be 8.9 by 20.5 meters. Would expansion joints be another area that might leak? I am not putting steel mesh in, but i might, if this cracking was considered to be significant in terms of loss of airtightness.

Any advice appreciated

thanks

SRV

sinnerboy

Leakage through the - I assume - ground floor slab should not be significant provided that you have competently installed below it a radon barrier . Pay particular attention to seal the membrane where drains and ducts penetrate .

If you are tiling over an expansion joint then you should have a sealed movement joint there primarily to prevent cracking of the tiles . This joint should be sealed anyway for aestheic reasons so taking care of air tightness too .

If you are placing carpet or timber finishes over then you may care to bond a bituthene strip[ over the expansion joint first . Many would see this as a "belt and braces" approach ( I would )

No6

Air leakage is an issue with pre cast concrete units which require an air membrane wrapped around the ends of the as per the accredited constrcution details. I wouldn't think it would be a huge problem with ground floor slabs and there are no special provisions for such in the accredited details.

SRV

That makes sense now that I think about it.........thanks.

SRV