Plaster repair around new windows?

[roundthebend]

Hi

We had new UPVC windows fitted recently. The company suggested that we could increase our sill depth by having the new windows fitted further forwards, and we liked that idea as the current sills were very narrow.

The old window recess was finished with wood. The surround was then finished with an architrave. Due to the age and general condition of these I have removed them with the intention of refinishing the recess with plaster. OK, so I'm now at the stage of doing that finish and I have a few questions:


1. As the windows are now sitting further out towards the exterior, will I need to make provision for waterproofing/sealing? I say this because there is some black polythene lining exposed.


2. I intend to fit plaster board into the recess which will provide a smooth surface and also cover the untidy edges. Should I screw this in, nail it, or glue (dot/dab) it?


3. How can I finish the corners? Is it simply a case of good plaster skills, or is there a product that I can use?


4. What's the best product to use to skim over the plasterboard to cover the screw/nails?


Thanks in advance.

 

[noseall]

modern building practice requires the window to be located so that it partially covers the join between inner and outer leaves of masonry.

it sounds like your fitters have contravened this rule?

the d.p.c. separating the two leaves should, at worst, be just visible when the window is fitted*. at no time should any external masonry be visible from the inside.*


* these pointers are based on the removal of the reveal plastering, thus exposing the inner leaf of masonry.

 

[roundthebend]

Thanks. It's possible that my description and my eyes aren't quite correct. How would I get this checked? Who do I call to come and inspect this?

 

[roundthebend]

I spoke to my local council building control this morning.

They tell me that the regulations that 'noseall' states only apply to new buildings. They said it was a grey area how/if the rules could be applied to replacement windows.

He told me that the window should ideally overlap the cavity by 30mm, but with a house like ours (well known in the area as they were built by a development corporation en masse) the air gap was sufficient for this to not matter too much.

He said he would have difficulty in finding an issue with the work we've had done. He did however suggest that we make sure the waterproof membrane is reattached to the window and suitably sealed.

I intend to ask the fitters to come back and do that so that I can clad the interior surfaces afterwards.

 

[noseall]

the problem with having any amount of external masonry visible, beyond the internal side of the window frame, is that in prolonged driving rain you can get damp patches appearing on the window reveal plaster.

 

[roundthebend]

That was exactly my concern when I looked closely at the resulting situation. The fitter is coming over on Friday and I shall ask them to waterproof from the membrane to the window frame.

I can DIY that if necessary, but I think it really is/was the duty of the fitter (who I paid £2500) to make sure that regulations were complied with and that simple things like waterproofing were, at least, mentioned.

So, assuming I'll have a waterproof seal.....

Should I glue the plasterboard in place, or screw/nail it?

How should I finish the corners - I'd like to paint over it?