Patio door sill and decking

4 Jan 2024
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United Kingdom


I would really appreciate any advice. I want to finish off this patio door installation properly (the builder has fecked off and won’t return my calls).

The door has been installed on top of the internal timber frame. There is then a cavity, and a single brick foundation with concrete block wall above it forming the outer skin of the building.

I want to build a deck up to the patio door. My thought is to install a concrete sill under the patio door first. Then concrete in posts 300mm from the brickwork. Install a timber frame for the decking, with an additional box step on top, which would allow the decking to be level with the white pvc sill.

Would this work? How would you do it?

The gap between the underside of the pvc door sill and the brickwork is about 50mm.



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Your decking should not obstruct the vent or meeting the building without a gap to avoid damp brickwork.
Hi, thanks for your reply. I agree, that’s why I planned to install the deck frame into concrete posts away from the brick wall, to ensure the air bricks will not be blocked. The other option I considered is to use a ledger board on the wall, leaving gaps where the air bricks are, and using stainless washers to give a 15mm air gap. But I have read that single skin brick is not structurally sound enough for this. Does anyone agree or disagree with that?
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