Replacement windows

[dynst2000]

I am having double glazed sash windows fitted this week.

I live in a Victorian terrace and they are replacing the old wooden sash windows with UPVC units.

They have removed the first window in the back bedroom and put the the unit in. It has a gap around it of around 150mm (sides and top). I can also see a gap of around 10mm between the window and the outside wall.

The fitter has said he will insert wood into the gap, expanding foam and cover with plasterboard. Not sure what this will do for the gap outside.

Can anyone tell me if this will this offer good enough insulation around the window from noise and cold or or should the gap be filled with a solid insulation?

Sorry I don't know the terminology but I have seen solid insulation being being used on walls, attics etc called Kingspan and Celotex.

We are fitting these windows because the old sash are so poor for insulation, noise etc and I don't want to end up in a similar situation once these are in.

Any help would be appreciated.

 

[Gazman16]

150mm sounds a bit big but could be something to do with the construction of your house.
Can you show a pic inside and out

 

[dynst2000]

Thanks for this I will get a couple of pics and put them up.

 

[DHFrames]

Replacing your old timber sash windows with casements will leave approx 150mm gap to sides and top, this sounds like you are having casements installed. If you're having pvc sliding sash window the gap will be approx 100mm round.
They will fix timber in those voids then plasterboard and skim.
The 10mm gap is common, the windows need to be put in plumb, Victorian stonework is notorious for not being level/plumb

 

[Gazman16]

Sorry I thought you said you were having PVC sliding sash windows fitted.
150mm for casements is normal.

If you look at the outsides you will see that if they were made much bigger the opening sashs would be behind the brick making them unusable.