My house is a 1900-ish terrace with most of the original sash windows. A couple of years ago these were refurbished and draughtproofed and so are all in good condition and offer reasonable draught and sound insulation.
However, because of sporadic noise from a nearby factory I've decided to install secondary glazing units in the front bedroom (Easyglaze vertical sliding DIY kits, with glass separately sourced locally). The inside of the sashes is almost flush with the wall, so these will have to be surface mounted on the wooden sash boxes and the gap will be about 40mm, which is not ideal but the best that can be achieved.
To achieve optimal sound insulation I guess it would be a good idea to seal the secondary glazing units to the sash boxes. And here's the question...for best sound insulation how should this be done? I'm thinking of some kind of suitable thin tape, or maybe using a flexible filler.
Any suggestions?
TIA,
Dave.