Retrofit double glazing onto old single glazed sash windows

[JohnD]

start with the brush seals. It wil cut down draughts at the least cost and effort

 

[opps]

Thank you everyone, sorry I haven't been on for a few days. I can imagine how it's done now. The toughest bit I guess is routing the frame accurately to allow the double glaze glass to sit snugly. And then make sure it's completely draught proof. There are some movement between the windows and the outer sash box that cant be fixed with just beading. Do you recommend adding a trim of hard wood to the window so it sits tight within the sash box?

And last question is, where do you recommend to custom-order the double glaze glass from?

Some movement is advantageous, especially if you fit easy glides. They are nylon profiles that will help to centre the sash as it moves up and down. If you do opt to use them, you may need to plane a bit off the edges.

Before ordering DGUs, you need to remove the windows and weigh them. Then calculate the weight of the gland the weight of the DGUs. There is little point buying everything only to discover that you won't be able to source sufficient counter weights.