Door into/level with cavity?

Ian H · 5 Oct 2019

Good morning.

I’m looking to replace a rotten wooden door and side windows with a upvc unit.

It’s currently fitted into the cavity and is plastered on the inside. How would I go about measuring and fitting the new unit?

Thanks

Deleted member 174758 · 5 Oct 2019

I assume that by cavity you what we would call a rebate. Well, on sash windows you would have to cut-back the plasterboard/plaster to enable you to get the old sash box out and/or measured-up and a new (or repaired old one) back in. Same applies here. Chop back a small area of plaster on one side until you can see the edge of the masonry rebate and measure from that to the glazing (not the plaster as that can vary). Normally you'll have the same depth of rebate on both sides and at the head so you should be able to work out the sizes needed.

Notch7 · 5 Oct 2019

if you wanted you cold make the new smaller than the brickwork opening by about 10mm or so (overall) and when in trim around after installed....it depends on whether the plaster is being re done anyway on the inside.

Dont forget though you will need a way to fix the new frame -possibly with straps?

Im guessing it is the old front door that you put a porch over? -in which case did you want upvc or do it in timber as its internal?

Ian H · 6 Oct 2019

It was the fixing I was wondering about.

I thought to chop out the old wooden frame and have the new one slightly smaller than the brick opening. Then I wanted to press the new one against the plaster but then couldn’t fix it as I normally would.

I’ll look up the straps, if they could fix into the bricks that would be good because that’s getting plastered soon.

Deleted member 174758 · 6 Oct 2019

They were using straps to secure doors and windows in rebates back in the Victorian era (I'm saying that because I've hauled a few out for repair over the years) and the local builders merchants should be able to supply galvanised steel straps or perforated banding like these two examples below:

OK, so the examples are windows (and the green one is also in aluminium) - but the principle is exactly the same. As the straps are hidden beneath the plaster work neatness is really a secondary consideration - flatness/straightness is far more important. These straps should ideally fix directly to the masonry and not through plaster work which is relatively soft and friable

In order to get the old frame out and get the new one in it will be necessary to chop out some of the plaster work and make good after the installation.

Ian H · 11 Oct 2019

On the bottom picture have they strapped and foamed timber into the cavity and fixed the door into that?

I think i’ll foam some celotex into the cavity then fit the door with straps.

Thanks for the tips

Deleted member 174758 · 11 Oct 2019

The straps will have been fixed either to plywood or into masonry - foam won't hold anything. You'll need 2 or 3 straps each side, depending on the size/weight of the window

Ian H · 15 Nov 2019

I’ve got the door now but struggling to find the straps. I’ve tried Windowplas and Eurocell.

Other option is these from Toolstation:

Any good? And if they are is there a preferred screw type for fixing them to the frames?

Ian H · 20 Nov 2019

All done now and looks really good

I put 4 of them on each side, fixed to the brick then foamed the gaps.

Ian H · 20 Nov 2019

The opening is 50mm wider on the inside. I didn’t notice that when I measured up!!

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Door into/level with cavity?

Deleted member 174758

Deleted member 174758

Deleted member 174758

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