Repairing and maintaining sash
Sash windows are an intrinsic part of a period
house and should be repaired rather than replaced if at all
possible. Fortunately, although the mechanism may look complicated,
replacing a broken cord is a job you can do yourself in a few hours.
If you have a broken sash cord, the window will be
difficult to open and judder as it is raised or lowered. If both
cords are broken, the window will not stay open.
It's best to renew all the
cords if one has rotted.
Removing the sash
Prise the narrow beading away from the interior of
the window frame with a wide-bladed paint scraper or an old chisel.
Keep both hands behind the blade when cutting and wear work gloves
and safety glasses to avoid splinters.
Start in the middle of one of the side beads and
bend the moulding gently outwards until it springs out of the corner
joints. Remove the three other pieces and keep to one side.
Make a note of their positions
to make replacement easier.
Removing the sash cord
It's best to
have a workbench of some sort for the next part.
Swing the bottom sash window carefully into the room and support it
on the bench. You now need to Gently lever out any nails holding the
broken sash cords to the window frame. If you are replacing old one
which are not broken, remember that the weight will still be acting
on it, and will shoot down inside the frame when you release the
nails on the sash. So make sure that you hold the cord with one hand
while prising out the nails, to prevent this happening. You can then
lower the weight gently.
Lever out the narrow parting bead which
divides the two opening sashes and remove the upper sash in the
The small slip of wood at the bottom of
each frame side may be loose fitted or screwed in place. Remove this
to reveal the lead weights. Vacuum out any building dust in the
bottom of the recess and remove the weights and broken cord.
Replacing the sash cord
Pass a piece of string with a small weight at the
end over the first pulley and allow it to drop to the bottom of the
jamb. Attach the other end of the string to a length of the new cord
and pull this over the pulley. Use a non-slip knot to tie the cord
to the weight.
Most weights have a hole in the top, through which
the cord can be passed. Once the cord has been threaded through
this, a figure-of-eight knot can be tied and pulled back into
the recess in the top of the weight.
Lightly oil the pulley if it is sticking.
Pull the weight upwards until it touches the
pulley, and lower it around 100mm. Rest the upper sash on the window
ledge and use galvanised clout nails to fix the cord into the groove
on the side of the sash. The highest nail should be fixed at a
distance down the groove, at least equal to the measurement from the
top of the window frame to the bottom of the pulley, otherwise it
will not close fully. Once fixed, trim off the end of the cord.
Replace the parting bead by tapping it into its groove. Then repeat
the procedure for the lower sash.
Easing the window
Check both windows work without
juddering before replacing the beading.
Rub a candle up and down the sash
sides to make them run smoothly. If the sashes still stick, you may
need to take a few shavings off the sides with a hand plane.
Some larger windows may use chains
instead of weights. Replace these with new chains, available from
larger hardware stores.
cover North London and Northwest London, from Queen’s park, Kensal Rise, Kensal Green, Willesden
Green, Notting Hill, Holland Park, Kilburn, Hampstead, West
Hampstead, Maida Vale, St. Johns Wood, Hendon, Golders Green,
Brondesbury Park, Primrose Hill and Belsize Park