Month: July 2023

Box frames and Spiral balances

Work in progress

We have 2 similar jobs on the go right now, but there is a difference in how they operate; weights and pulleys versus spiral balances

These are single hung cedar sash windows. They will operate using a spiral balance tube on either side of the sash. The spiral balance means no weights and pulleys/ropes are needed. You can get custom made heavy duty spring balances for heavy glass up to about 36kilos.

A standard whitco spiral balance. suitable up to 14kg
Heavy duty spring balances.
An example of heavy duty balances from Schlegel. Thicker tube, custom made for specific orders. Up to 36kg.
Cedar Boxframe windows being assembled – sashes are not in.

These are box-frame sash windows being assembled. Both top and bottom sash will move up and down, using the pulleys on the side, with rope and to the weights which will be hidden on the side boxes (hence box-frame).

This is the traditional method of sash windows, but because you need to hide the weights you have more timber and less glass/view than using spiral balances.

The bigger / thicker the glass = the bigger the weights need to be – making them very heavy in some circumstances.

Convert window to french doors – wallcut

Finished Product

On Wednesday we made a wall cut and removed an aluminium window. Added a meranti doorframe with sill and pair of rebated doors.

Client will render edges and add bricks under the sill when ready (has a pipe underneath with a tiny rustleak that needs to be fixed first).