Repairs around window help please

[John D v2.0]

Hi all just wondered if anyone has any guidance they are happy to share with this work:
Back story is we had Windows and new bay window columns fitted about 3 years ago. 1920s solid wall house. Due to budget we were left to make good on the inside. We managed to do downstairs and one bedroom to basic DIY standard and now we need to get the other bedroom ready which we would like to do a bit better.
The main difficulty with the other ones was differing suction of the old wall and new hard wall backing plaster so patching went badly even with copious PVA. The plaster is hollow throughout the house in many places. Complications affecting this window only are the lath and plaster above the window and the movement cracks caused by replacing the columns below.
Anyway i won't write an essay but ask for more details or photos please! Thanks in advance for reading.
Click to zoom in.

 

[KenGMac]

John D v2.0, good evening.

How about considering removal of the old plaster below the windows and also removal of the lath and Plaster above at lease the front facing window, replace with dot / dab plasterboard + skim below and plasterboard + skim on to the timbers holding the lath above the windows?

Would be nice to introduce some Insulation?

One draw back is the slopes above the two side windows?

Ken

 

[John D v2.0]

Hi @KenGMac thanks very much for your help and suggestions. I never thought about plasterboard but that's definitely much simpler so I'll do that for sure!

Re slopes yes it's all a bit more advanced then the other rooms I tried! I forget the name of the roof design, but the original rafters are built into the top of the walls with exposed feet, and the ceiling/ties are nailed part way up the rafters, that caused no end of trouble on the extension! Anyway the ceiling and slopes pictured are also L&P and that front gable area is uninsulated due to obstructions, I'm sure there's an element of "in for a penny in for a pound" with these jobs and I can re-plasterboard and insulate there too unless you see any drawback?

Once I'm at that stage I think my main issue would be finishing off the cills/reveals. They are very narrow due to the deep window frames, and especially where the two windows connect together it's not clear what to do. Would you try to do something with thin strips of plasterboard, or cover these areas with strips of timber trim? Cheers! John

 

[KenGMac]

John D v2.0, good evening again.

You could consider making timber frames which would be fixed to the walls, as an aside this could?? result in not having to remove the plaster at least below the main front window.

The above would then allow a couple of things, One, voids in the frame could be infilled with Insulation? and Two, it would allow a wider area into which you could fit timber sills? as for the sills you could use cantilever brackets to support the sills?

There are several ways around the issues? and given it appears to be a fairly large window the " loss of" 40 / 70.mm allowing for the frame should work?

Ken

 

[John D v2.0]

Thanks again that's useful, timber frame sounds like a goer especially if it saves some mess. The overall loss of space should be minimal as you say and a free shelf can't be bad!
Presumably we should use some 0.125 poly sheet vapour barrier in front of the studs and insulation and behind the sockets just to avoid any mould? There will be 2 sockets on the sides.

 

[KenGMac]

John D v2.0, good evening again.

Short answer is yes to the V/B

Either plastic or you may want to consider Foil Backed Plasterboard?

Ken

 

[John D v2.0]

thanks @KenGMac I've just been and got a roll of this that I can staple on the studs https://www.wickes.co.uk/Wickes-Green-Polythene-Vapour-Barrier---2-5-x-20m/p/153230
and I already have some 70mm celotex and glass wool, so I will use one or other of those between the studs! All the best, John