Hi everyone. Im new here so be gentle :)

I recently discovered some blown plaster in a ground floor room either side of a large window. Ive successfully repaired the leak outside which caused the problem.

While removing the plaster Ive been rather alarmed to discover *massive* gaps around the window frames. I can get a hand inside the gaps on both sides.
The mortar flaunches on the outside of the window are weak and crumbly, so this is almost certainly how the water got in.
Ive hacked the blown plaster back to the brick either side the window, Its all bone dry.





The stuff Ive hacked off has been grey and powdery while the unaffected plaster directly below is modern and solid.

Will expanding filler be appropriate to fill the gaps by the window?

Is there any particular mortar recipe I need to fix the outside flaunching?

Close ups of the gaps.

I had this in a house once, as long as you have sealed the windows from the outside you could...

Whack some cement into the holes, leaving flush with the brickwork.

Then where the render has come off inside you have two options.

1. Fill with a backing plaster such as hardwall

2. Fill with render (a better option).

Then I would get the walls skimmed floor to ceiling to hide the repair.

As far as externally goes you can seal with silicone, upvc or pug up the reveals with some cement.

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Thanks for the reply. :)

So I should start with the outside first and repair the flaunching?
Will a cement/ mortar mix do it? I'll post photos of the damage later.

As for inside, rather than expanding foam- I should fill the gaps with cement.
Is there any special technique for filling a vertical gap?

There is no "technique" as such, but just mix the sand and cement 4:1 and trowel it in. You can use expanding foam if you find it easier, then go over with bonding/hardwall/s+c when you are patching up your other areas.

I dont like using expanding foam unless there is no other option, but that's just personal preference.

When fitting windows and I am left with a big gap (due to un-true walls or dodgy estimating) I fill the gaps with sand + cement, mixed with waterpoofer, paint when dry (leave a week to be sure) and it will look dead professional once finished.

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Thanks so much for the reply! It seems eminently do-able for an amateur.

Alternately I had a builder come round about half an hour ago and he said he'd fill the gaps, seal, render and skim the walls for £330.

Is that a good deal?

Skim all the walls floor to celing? Does that pirce include materials?

If yes to both of those I would say its a very fair price.

If hes only reparing certain areas when he skims and you have to supply materials, I would get another quote.

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Hi Crooksey,

No, he's not doing the whole wall floor to ceiling. Its an area half a metre high by 4 metres in length, plus ten centimetres around the window frame.
He did suggest doing the full wall, but he agrees that the rest of the wall seems sound.
Anyway, I can fill any cracks at a later date.

He's supplying materials.

I thought it was a decent deal, but over the weekend I was told by a builder that a London plasterer would be hired in at £180 a day. In my lay opinion this job is half a day's work in total.

What do you think?

When I sub out plastering I pay £130 a day, but I know some people who charge between £150-180

I would pay an extra £50 to the builder and ask him to skim floor to ceiling, well worth it.

Tell him "you've got the job if you will do a full skim for an extra £50 on top".

The pictures you have shown would be a 2 day job (1 and a half maybe).

He has to fill the holes on one day and also seal round the windows, then plaster on day two (should really leave an extra day if he is using sand + cement though).

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Hey Crooksey, thanks for the reply and pricing information. Its really helpful.

OK- I now have 3 quotes in total now. None include floor to ceiling skimming, the quote is just for plastering the damaged part of the wall.
I will do as you suggest and offer an extra £50 on the day.



Quote 1) The original one I mentioned.

£330 for sealing the wall, cement render, filling the gap around the window frame with cement and a skim finish.


Quote 2)
£200 + materials or £240 all in.

This one requested:
4 x bags sand
1 x cement
1 x multi finish
1 x bead rendering
1 x sika cement waterproofer.

He wants the Sika waterproofer and says its better though more expensive than say Wickes or B&Q own brand (?)

3)
The third quote was for £150 all inclusive by a neighbourhood handyman/ decorator. Communication was difficult as he doesnt speak English at all well, but he seemed to know what he was doing (?!) and was highly recommended to me. I was unnerved by the low quote.

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The size of the gap around the window apparently isnt an issue. All have opted for cement rather than expanding foam. The lime mortar between the bricks wont be a problem as long as the PVA prep is well done.

I was told that cement render is preferred to bonding because the existing plasterwork is about an inch deep.

Well I buy the following at:


4 x bags sand £1.80 each
1 x cement £1.50 each
1 x multi finish £3.99
1 x bead rendering depends on the bead, say £2 max
1 x sika cement waterproofer. - I use travis perks waterproofer which I buy at £9.99

Total: £24.68
Total inc VAT @ 20%: £29.62

Some waterproofer is more expensive than others, so could be why the £40, plus he has to collect them etc, so I would say its a fair price.

If you want the whole walls skimming, you will need more multi finish, so needs to be negotiated before he turns up.

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