Problems and Maintenance of Traditional Sash Windows

The traditional hardwood sash window frame is generally found in properties that were built between the 19th and 20th Century and work through a series of pull cords and weights. One end of the cord is nailed into a groove at the side of the sash, and the other end has a weight attached, the weight itself is tucked into a weight box.

Due to most of the traditional sash windows being fairly old now it is not uncommon to come across problems with them. If you maintain them well and repair any issues as they arise there is no reason they can't last for many more years down the line. An appearance of rot or warping in the wood is generally only superficial because most good quality hardwood can be easily restored. If the window is of poorer quality or made of poor quality wood the chances of restoration are less likely and if the damage is extensive then you may need to replace the window altogether.

Do not be put off by chipping, dirty paintwork. If the material beneath is quality hardwood then your sash can still be restored.

Why carry out an annual window inspection? Deterioration of the windows is likely to begin at the joints and on horizontal surfaces, as this is where moisture will collect when your windows are open.

Renovate before replacing. Hardwood sash windows are designed to be easily taken apart so that they can be repaired or replaced as they were made during a time when products were built to last many generations. Be aware that modern UPVC sash windows are not made for easy dismantling and will need expert attention. Getting a newer version is not always as advantageous as it seems.

Problems With Sash Windows

Some of the most common problems that arise with old sash windows are:

Draughts
Rattling
Sticking
Rot

Preventing draughts coming through your sash windows - Around old sash windows the gaps can be substantial, costing you more in heating bills and using up more energy. Good draught proofing for windows is essential, especially finding a discreet proof that does not overshadow your authentic windows. Draught proofed beading can be fitted, and there are now many specialised joinery firms who can insert brushes or seals that are very effective.

Brush seals are fine nylon fibres, though you can also purchase seals which consist of urethane foam in polypropylene. Your savings on heating bills will recoup the cost of fitting draught proofing for windows in 5 to 25 years; less time than that of replacement UPVC. Draught proofing measures are also effective against rattling, as any gaps in the sash window will have been sealed.

Stop sash windows sticking - Firstly ensure that your window is not sticking due to a slightly messy paint job. If this is the case, carefully draw a knife or chisel along the edge to free it. If the reason for sticking is unknown, rub some wax into the channels and sash stile. It may also be advisable to gently oil the top pulleys and replace the sash cord, checking the beading is correctly seated.

If you find excess dirt or paint in the window channels prior to waxing, you should carefully scraped it out and gently sand the area to be treated. If you feel that this is not adequate, strip the paint from the frame's channels and coat it in teak or linseed oil, as these were the original protection methods used.

If all else fails, inspect the sashes for warping or swelling. If you find the wood is not straight or is warped at any point you would have to remove the sash and plane the excess wood off so that the window can be opened and closed easily.

Preventing your windows from starting to rot - Superficial damage from rot can be easily rectified by applying wood treatments. Firstly you should clean the area thouroughly and remove any debris and then apply a wood hardener. Use a two part epoxy filler and then prime your window with an undercoat and up to two top coats.

If there is extensive damage then you will be have to remove the sashes and use a chemical stripper, and sand down the sections you want to keep.

Removing Window Sash Windows

To carry out major renovations to restore rotting wood, replace a broken cord, or release internal sticking, you must first extract the sashes from the window frame. If the damage is extreme then you may want to hire a professional to carry the work out for you to achieve the best finish. Although in some cases if the damage is irreparable then you may be forced to replace the window completely, this is why maintaining your sash windows is highly important.

Prise off the outer stop bead with a chisel either by leverage or by trying to tap it back sharply to cause the securing pins to come loose. Before removing the lower inner sash, mark with a pencil on the sash and on the frame where the ends of the sash cords come. Then gently lift out the lower sash, taking care not to drop the weights if the cord is broken.

Again, use the chisel to ease out the parting bead and then lift off the upper outer sash. Do not forget to repeat the markings as above. Weight box covers or "pockets" can then be unscrewed so that the weights can be fed through the pocket openings.

Replacing the cord on a sash window - Feed the new cord over the pulley as used by the original cord, passing it through from the window side, into the boxing toward the weight box. The new cord can now to be tied as the original one was.

On an upper sash, put the side that has the existing cord back into its place in the frame, and position the sash itself around 4 inches up from the window sill. Then pull the replacement cord until the weight goes into the box and hits the top. Once in this position, nail the cord in place and tie the same way as the original cord. As the sash is replaced and pushed up, the cord will fall. On a lower sash the weight should be at the top of the box when the window is on the bottom.

To complete, reattach the centre parting bead, replace the bottom sash and attach the outer stop bead.

Reglazing Plain Glass

If the glass has been broken or you just want to renovate the entire window at once, replacing plain glass can be relatively unfussy. If carrying out the work yourself always be sure to have a full knowledge on the process of reglazing a window and that you have the right safety equipment before starting your work.

First, carefully knock out the glass and chip out the putty. If the putty proves difficult to remove, soften it with paint stripper or bleach covered with Clingfilm.
Remove the nails (glaziers points) that hold in the glass.
Measure the inner window frame and subtract 3mm from the height and width.
Roll the putty in your hands until it becomes a rope and press it into the frame.
Position the glass into the window and press firmly around it. Tap the glazier points back into place.
Press a second putty rope around the edge, and smooth using a wet putty knife.