Blocking up external doorway

[P.J.]

Hi All,
I've searched for this but couldn't find what I'm after.
I'm bricking up an external 900 x 2100 doorway - I'm doing the block inner leaf and a pro's going to do the outer leaf. I've a few questions:

1. With the door gone, I have a concrete screed floor at the base, can I lay the inner leaf blocks straight onto this ?

2. Do I need to remove the plaster/render down each reveal and at the top of the opening before laying the blocks or can I just 'fill the hole' ? I'm going to tie the blocks to each side of the opening using a metal bracket every 2 courses, and put a wall tie in every 2 courses for the guy to tie his outer leaf to.

3. Do I need to incorporate any d.p.c. around the opening. If so, does anyone have any views of how to fit it please ?

Thanks in advance,
P.J.

 

[JerryD]

The inner leaf can be built on the screed but the edge of the screed (where it projects past the blocks into the cavity) should be cut back flush with the back of these new blocks. This give you a continuation of the cavity below dpc. This cavity should be minimum 2 courses of bricks deep (150mm).

Similarly it is recommended to cut back the cavity closing plaster a bit to avoid any chance of the new outer brickwork 'bridging' the cavity vertical damp. So cut back the plaster margins (where they butted against the frame you remove) by a couple of inches.

No dpc is needed anywhere on the inner skin in your situation, the screed is already waterproofed with a membrane under it, but you may feel it a good idea to lay a strip of dpc on the screed just to be on the safe side. (it can't do any harm)

It is a good idea to remove the three angle beads from the plaster corners on the inner face of the wall and cut back the plaster an inch or two. This makes it easier to blend in the new plastering (those angle beads would otherwise always show where the doorway was).

Set your new blockwork back from the finished plasterwork about 15mm to allow for the new plaster. You'll need some cavity batts for thermal insulation (assuming your house has cavity wall insulation).

 

[P.J.]

JerryD,

Many thanks for your comprehensive reply. That's a great help.

Cheers,

P.J.