Extension shell, how to finish internal PVC window?

[oldman2]

The window has been fitted and finished outside, but all I have inside is 2 vertical cavity closers which dont fit well, convexed where they fit into the cavity & nothing where a sill would be.

View media item 14292
The room (kitchen) is due to be plastered next week, so before then I would like to get this bit sorted out.
Does the plasterer usually finish up to the pvc window boards or is it usual to fit these after he finishes?
I have seen bull nosed plastic sill for sale and assume if using this I dont need a cavity closer for the sill?
For the sides and top (metal lintel showing) I guess some 9mm flat pvc board is normally used?
Are these usually stuck on with something like no nails?
Depth of sill opening is 195mm max.
Walls will be painted after plastering with just 150mm of tiles as a splashback above the worktop

 

[noseall]

Fix a length of cav closer to the sill too.

If they are not snug fitting then apply foam to any gaps and they will be rigid by tomorrow. Make sure you straighten them up first. You may also have a problem with mortar snots on the inside, these should have been chiseled off prior to fitting the c.c.'s.

Once the cav closers are set dab plasterboard to the entire widow reveal. Make sure the sill reveal is especially true and level. Once set you can the fix mdf widow board to the sill by squirting blobs of adhesive to the sill board.

The other three reveals can be beaded and skimmed.

 

[noseall]

P.S. It is better to dab all the walls then do the reveals.

 

[oldman2]

Thanks noseall, the room is being hardwalled, no plasterboard on the walls, except maybe around the window now

I think as you suggested the mortar snots were not removed as the manky old closer they fitted sits proud of the inner blockwork in places. Not sure I can remove these now either as I guess they are trapped behind the d/glazing unit.

View media item 16599

 

[noseall]

Just straighten 'em up as best you can then foam 'em.

So long as they are not prohibitively proud then you will be ok. the bonding compound will deal with any discrepancies.

 

[oldman2]

ok I have cleared the mortar that was holding the side closers too far out and used no nails to stick them to the blockwork.
I put some timbers on top of them and wedged other timbers horizontal against them to force them back hard against the blocks while the adhesive went off, so they look fine now.

The sill part is going to give me a bit more grief though as the window and outer sill has been fitted flush to the outer brickwork, so there is nothing to hang a closer onto other than the blocks.

View media item 16686
There is plenty of insulation in the cavity, I pushed it down for the picture.
So I am wondering if I can just bond a window sill board using pvc glue to the outer sill part showing in the pic to stop cold bridging?
Plasterboard would then go over it ready for plastering.