New doorway in cavity wall

1 Jun 2009
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United Kingdom
I have just cut a new doorway in a cavity wall, through from the kitchen into the new extension. This was originally the external wall prior to building the extension. I have two questions: 1. Do I just use concrete lintels above the door on each skin, extending 6” either side? 2. How do I make good the base of the doorway, with respect to the dpc and the existing cavity? – I assume the cavity here needs to be filled in with concrete but would need its own dpc preparation first?
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P.c.c. builders lintels, with 150mm end bearing are commonly used for standard doorway openings.

The bricks should be hacked out to at least 1 course below dpc. You then line the trough with 1200 gauge polythene and make good with concrete or screed.

The vertical cavity can be bricked up with block slithers or use proprietary closers.

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