Sealing around window

[loziv]

Hi

I am having new insulation and acoustic plasterboard installed, but when we pulled off the trim around the window, you can see the outside!

What is best for filling in this gap foam?

 

[theprinceofdarkness]

You need silicone goo on the outside. If you use foam, you will see brown bubbles from the outside and I am not sure it will be watertight enough. I can't if there is any depth to the area you want to fill, I would run your new boarding right up to the frame.
Frank

 

[loziv]

The problem as well is when they installed the window there is a piece of plastic either side of the window that runs from the inside to outside as shown in the pic below. So I cant really remove this as there would be

about a 3 inch gap either side

 

[mfarrow]

They either made the windows too small or there was another obstruction which necessitated the plastic on the right. Either way you need a silicone as suggested on the outside.

Ps that was probably the reason it's so noisey, the gap and covering it over with plastic...

 

[theprinceofdarkness]

I would use silicone on the outside first, then on the inside. I guess the side to side gap is your 3", but how deep is the gap between the inner wall surface and the inner surface of the window surround, or the depth of that on edge plastic plank. If its over 1/4", I would PVA the edge of the existing wall and fill the gap with mortar up to the surface of the existing wall, as you are going to board over it anyway.
Frank