Closing cavity at floor level.

[andynumpty]

Hi, I am building a new extension & need some advice please.
I have used the insulated plastic cavity closures on the vertical openings but what is advised for the horizontal opening at floor level, 3m wide?
Thanks.

 

[noseall]

The flooring material, i.e. concrete or screed should be made good right up to the door threshold. This usually means removing the final course of bricks, lining the trough with polythene then filling with screed or concrete to finished slab/screed level.

 

[noseall]

If you have a timber suspended floor then similar applies, you just make good floorboarding right up to the door threshold.

 

[andynumpty]

Hi, thanks for the replys.
The floor is a concrete slab. The inner blockwork is level with the slab level at the moment.
So the best thing is to remove a course of the inner blockwork, visqueen, then fill in the whole cavity upto the outer brickwork.
Hope my answer is clear.

 

[noseall]

Hi, thanks for the replys.
The floor is a concrete slab. The inner blockwork is level with the slab level at the moment.
So the best thing is to remove a course of the inner blockwork, visqueen, then fill in the whole cavity upto the outer brickwork.
Hope my answer is clear.

We tend to lay a sub slab then lay a screed on top later on in the build. This means that we can remove brickwork after the door openings have been set out above dpc, then make good the floors up to the door thresholds, without any scarring.

If you are laying a trowel-finished slab in one go then you should build the door reveal detail so that it is formed below dpc, and prior to laying the concrete. This then allows the slab to finish at the threshold.

However i don't envisage any problems doing it as you describe.