Best sealant?

[nervous123]

Glazing firm left a gap inside, where windows meet the wall. About 3mm wide and up to 2cm deep. There's a whooshing sound when it's windy and a slight breeze.

Any tips what's the best stuff to use to seal it? (available from e.g. Screwfix, B&Q etc)

 

[foxhole]

Should have been sealed at installation, but you should be able to use a 'frame sealant' to seal now.

 

[hillw]

If you are sealing the inside then acrylic sealant also knows as caulking is best.
However if you are getting a 'whooshing' sound then the external sealant may not have been done properly either, so check that as well.
It definately should have all been done on installation, but if you are choosing to finish yourself, then use a low modulus sealant externally.

 

[nervous123]

Thanks a lot guys.