We have two sash windows that use spiral balances. Put in by a builder yonks ago. I'd quite like to replace the sashes and also make the double-glazed. I have revised my views of those duplex bars as well as it means a cheaper double-glazing unit rather than 16 smaller units. So here's the plan and grateful for any input.
The existing sashes are 43mm thick. Now my glazing company tell me that the duplex bars are 18mm deep to fit inside a 20mm gap unit. So total dgu thickness 28mm (4-20-4). So I need to make the sashes out of 50mm (being about the thinnest I reckon I can get away with. The bottom sash is designed to be swung down for cleaning the outside.
So I reckon I can easily add 7mm to the thickness and cut away just the front edge of the bottom rail of the frame to allow for the extra thickness.
The plastic gizmo that slides up and down the outside of the spiral balance can be mounted offset to compensate for the extra width.
The top sash is more problematic as it (a) slides up and down behind this plastic moulding
and so I plan to slice off the plastic to accommodate the extra thickness and securely fix a bead to the wood surround.
Is this a goer? Any gotcha's?
Spiral balances. Never used these before but will I need a different strength spring because of the extra glass in the dgu? Or do I just wind-up the spiral on the existing one and how do I know by how much to wind it?
TIA.
The existing sashes are 43mm thick. Now my glazing company tell me that the duplex bars are 18mm deep to fit inside a 20mm gap unit. So total dgu thickness 28mm (4-20-4). So I need to make the sashes out of 50mm (being about the thinnest I reckon I can get away with. The bottom sash is designed to be swung down for cleaning the outside.
So I reckon I can easily add 7mm to the thickness and cut away just the front edge of the bottom rail of the frame to allow for the extra thickness.
The plastic gizmo that slides up and down the outside of the spiral balance can be mounted offset to compensate for the extra width.
The top sash is more problematic as it (a) slides up and down behind this plastic moulding
and so I plan to slice off the plastic to accommodate the extra thickness and securely fix a bead to the wood surround.
Is this a goer? Any gotcha's?
Spiral balances. Never used these before but will I need a different strength spring because of the extra glass in the dgu? Or do I just wind-up the spiral on the existing one and how do I know by how much to wind it?
TIA.
