Do It Yourself Sash Window Guide
Should you wish to completely recondition a sash window or simply need
to remove the sashes to get large furniture into the property then these
guidelines can be utilized. These guideline are for the most common
sliding box sash windows encountered. It should be remembered
however that not every sash window works in exactly the same way and regional
variations are not uncommon.
We receive plenty of positive feedback from across the world regarding
this DIY guide.
These guidelines are written for work to be undertaken from inside
of the property.
This information is given to the best of our ability,
but is given expressly without any liability on our part.
|A box sash window operates by counterbalancing the weight of the sash
against weights attached to a cord and passed over a pulley. These weights
(generally cast iron or lead) travel up and down in a box, concealed within
the window frame, hence the name Box Sash Windows. A dividing strip is
often suspended within the box to prevent collision of the weights.
Access to the weights is by means of a removable pocket, usually cut
into the inside of the box lining but occasionally found in the box face
behind wooden shutters.
Parting beads are set into grooves running down the length of the linings,
holding the pockets in place and separating the top (back) sash into its
own channel. The channel for the bottom (front) sash is formed by the Staff
Bead running around the perimeter of the lining.
- Remove the staff beads - Using a sharp knife carefully slice along
the paint joint formed between the staff beads and the box frame, this
will minimize disruption to the paintwork. Using a mallet and
a blunt chisel (25mm+) gently tap the beads in towards the centre of the
window - The chisel should be sat into the small recess at the back
of the staff bead, starting midway along the longest bead. Once the
bead is free it can then be removed being sure to avoid injury on the protruding
nails. Repeat this procedure for the remaining beads. De-nail
the beads and set aside for reuse or disposal.
- Remove the bottom sash - If new cords are to be fitted: one
at a time cut the cord from the bottom sash and tie a knot in the end still
attached to the weight, allow the weight to be lowered until the knot is
at the pulley: Remove the sash. If the cords are not to be
replaced then gently remove the pins attaching the cord to the sash (or
untie the knot as appropriate) and tie a knot in the cord, slowly allow
it to rest at the pulley. Remove the sash.
- Remove the parting beads - Using a sharp knife slice along the paint
joint between the parting beads and the box frame. Gently prise the
parting beads from their grooves again being careful of nails or sharp
- Remove the top sash - If the top sash is inoperable it is usually
painted shut, but also check for nails or screws fixing it into place.
Carefully slice along the paint joint with a sharp knife, and tap the sash
gently until it is free. BEWARE it may have been
fixed shut because of broken cords and might drop when released. Remove the cords & knot as you did with the bottom sash.
- Remove the Pockets - The pockets should now be visible, using a
sharp knife slice along the paint joints around the pockets and gently
prise them out. (Traditionally pockets and parting beads are a snug fit,
requiring no fixings but over the years many have been pinned/screwed into
- Remove the weights - The weights should be visible in the
pocket, untie the knot suspending it and carefully remove it. Be
very careful when handling weights as they can easily cause an injury,
it is advisable to wear protective gloves.
- Repairs - Carefully inspect the sashes and the frame for any damage.
Chop out all effected wood and repair with an epoxy filler or splice in
fresh timber. Do not forget to treat the effected area with a multi
purpose wood preservative. If any of the sash joints are loose re-secure
them by gluing & re wedging the tenons. 2 part epoxy filler
also helps to bond open joints.
- Preparing the frame - Using a scraper remove any excessive paint
build up and sand the inner surfaces of the box ready for repainting. Ensure
that all of the pulleys are free rolling, use a spray lubricant on the
bearing to eliminate squeaking. Prime/undercoat any bare wood before
repainting the frame, acrylic paints are well suited to this purpose because
of their fast drying times. Ensure exterior grade paint is used.
- Preparing the sashes - You may also decide to repair broken
glass and/or re-paint the sashes whilst they are out. Any missing
or loose putties should also be replaced.
- Balancing the sashes - For the sashes to slide easily it is important
that the weights and sashes are balanced. Weigh the pair of weights and
then the sash (ensuring that any glass repairs are already complete), bathroom
scales are suitable. Adjust deficiencies in the sash weights with lead
'make up' weights. It is recommended that the top sash weighting
be a couple of pounds over weight to ensure a tight fit at the head.
- Replacing the cords - Pass replacement sash cords through the pulleys
and down out of the pocket. Often a mouse is required - Simply attach
a small weight to the end of a piece of string (the mouse), drop it over
the pulley and out of the pocket use this as a draw wire to then pull
the larger sash cord through. Securely attach the weight with a suitable
knot, including any make up weights required and replace into the frame.
Cut the cord leaving approx. 300mm protruding from the pulley & tie
a loose knot to prevent it slipping back inside the frame. If there
is no dividing strip between the weights it may be necessary to cut a strip
of hardboard or thin plastic sheet and pass it up between the weights and
pulleys. This strip prevents the weights from snagging each other.
Carefully replace the pockets.
- Re-hanging the top sash - Individually pull the rear cords until
the weight is at the top of the box, against the pulley. Pin the
cord to the box frame, leaving the head protruding for easy removal - Put
the pin where the staff bead will sit & well above the height of the
sash meeting rails. The weight is now suspended allowing you to attach
the cord to the sash. Sit the sash in position and tilt forward to fix
cords. Cords are fixed either by being pinned into a groove (1''
carpet tacks are ideal) or suspended on a knot. For knots simply
pass the cord down the channel & through the hole. Tie a knot large
enough not to pull back through, leave a short tail and cut of excess cord.
For pinned cords ensure that tacks are low enough to enable the pulley
to pull the sash to the top of the box without snagging, (If the distance
between the top of the box and the bottom of the pulley is X cm make sure
your top tack is X+20 mm from the top of the sash.) Remove the pins
attaching the cords to the frame and allow the top sash to slide into place.
Pull the sash through it's full travel, if excessive side to side movement
occurs then the sashes should be packed accordingly using timber fillets
if it binds it will need to be planed down. NOTE: If the window is
wider than it is tall then the length of the cords may have to be reduced
which will also reduce the opening of the sash.
- Replace the parting beads - Parting beads may need to be planed
to ensure that they fit snug in their grooves. Seal any gaps with
decorators caulk. The parting beads that we supply with built
in draught seals will need to be fitted in 2 pieces. Measure the
distance from the top of the sash to the centre of the meeting rails and
fit with the seal facing outside. The parting bead is reversed for
the bottom sash, fitted facing inwards. The join is not visible when
work is complete but a tight fit should be ensured reduced draughts.
- Replace bottom sash - Re-hang the bottom sash as you did with the
top. The bottom sash may need planing so as to bring the meeting
rails of the sashes level.
- Replace staff beads - Either refix the original beads in place
or measure the 4 dimensions of the box and cut replacement staff beads
to suit. These should be securely nailed into place, ensuring that they
are not so close as to restrict sash operation and not so wide as to allow
the sash to rattle. Use decorators caulk to seal the gap between
the staff bead and box, this will further help to reduce draughts.
- Hardware - Check that catches and locks are correctly aligned and
Use of silicone spray on the running stiles will help to improve performance.
Simon Free - WebMaster & Author
||This Web was First Published 1995 : Last Updated 2012