This guidance is suitable for sash windows which are sound but need some basic care, such as replacing ropes, dealing with sticking windows, draughts, rattles and minor rot.
If the sash ropes have broken, are worn or clogged with paint, they should be changed. Begin by removing the sashes.
Sticking windows can be eased with wax rubbed in the vertical channels and on the sash stiles. It may also help to oil the pulleys at the top of the window and to replace the sash cords to help them run smoothly.
If this does not help, check that the beading is seated correctly.
The third step is to strip the paint from the channels in the frame and protect it with linseed or teak oil; this is how these windows were originally finished.
Finally, test to see that the sashes are not distorted or swollen. Remove the sashes and plane off a little wood in the sticking area, or rebuild the sash completely.
Minor damage from rot can be dealt with using wood hardener; remove any very loose material, apply hardener to strengthen the wood and use a two-part epoxy filler before re-priming, applying undercoat and a top coat or two of exterior gloss or similar.
Use the instructions for reglazing.
Rattles can be stopped using little rubber wedges or by fitting a cam-style catch which pulls the two sashes together.
If you have draughts and rattles, replace the plain beading with special beading fitted with a draught-proofing strip. No-one can agree on whether it is best to keep heating bills down or to have fresh air blowing away all those 20th century chemicals - so make your choice.