Can you please ginve me some general tips on installing a double glazed unit
Answer:
If its in a wooden frame, set it into place and shim the bottom to square it. Now nail only the sides and not the top nor bottom. For insulation along the edges, use fibre insulation pushed in with a flat screwdriver instead of using foam. Make sure vapour barrier on the inside overlaps VB from the wall and then covers almost all of the backside of the window casing.
