Beam and block airtightness idea

[Chablais]

Hi Folks

Have been working away on extension and have the basement up to first floor level, floor is bison beams with block infill.  The existing house has beam and block floors and has always suffered from air ingress around the edges.

So I was thinking of taking Tony's idea, thathe used with timber joists and applying it to the concrete beams. This was to use airtight membrane sat on the bearing wall, then wrapped around the end infill and lapped up to the VCL in the new floor.

One issue is it creates a slip plane along the whole length of the wall that is build off the top, but then is any different to a DPC?

Are there any other solutions?

The problem is the mortar dryig out and cracking over time on all the cut blocks that fill in the ends

Or is it easier to address the airtightness when the screed goes in?

Has any one used the Soudal liquid membrane, which is spray applied, as this may also be a potential solution.

Been so busy on site not had time to post anything up, or even read the site recently. How do you all build houses and find time to be online...... I must be too slow.

Andy

[Declan52]

The damp proof membrane you put on top of the sub floor will stop any air coming up.  It will get overlapped with the dpc on the walls so will be no where for air to come up unless you puncture it. 

[Russell griffiths]

You could also use a liquid dpm painted around the ends and on the flat surfaces,before you put down your sheet dpm