Block wall dot and dab airtightness

[John D v2.0]

our extension is going up as dot and dab, block work, celotex(with gaps), cavity, concrete blockwork, render. The air bricks for the existing and new timber floors are under the dpc.

Should the inner leaf be parged with something first to stop draughts coming through the sockets and between the ceiling and the upstairs floor etc?

 

[tomfe]

If you are building to near/passivhaus levels or if your sap needs it, then yes. If not then it's up to you if the cost is worth it.

 

[John D v2.0]

Thanks Tom, OK well that is a no brainer then cos I'll do it myself! Free labour.

I can spread butter on toast so how hard can it be!