How to Restore Timber Sash Windows in Cambridge

Many homes in Cambridge have sash windows that are traditional and homeowners are proud of their appearance. However, sash windows may get stuck and be difficult to open or close. This is usually due to moisture, which can cause the timber to expand.

Box sash windows were traditionally operated using chains or cotton cords as well as weights made of lead. Modern sash windows feature hidden springs to solve this issue.

1. Aesthetics

Timber sash windows, in contrast to PVC-u windows that are made in imperial sizes, which are modular, are able to be restored to their original dimensions. This allows the restoration to be in line with modern energy requirements while ensuring compliance with conservation areas regulations. It also gives windows with a superior appearance than the uPVC alternatives.

Sliding sash window frames were initially only used for large buildings or public buildings. However, this changed when production became more affordable and artisans could produce larger frames with greater glass. In the 18th century, sash windows were the dominant design of wood in the majority of British homes. Sash windows were easy to operate and let light in rooms without the need for curtains.

Early windows were plain glass, but by the 17th century sash windows were becoming more decorative with coloured glazing bars and moulded mullions. These windows were quite expensive at the time, but as glass production improved and cheaper they became a feature of many period houses.

In the 19th century, it became possible to produce large, strong glasses that didn’t need support bars. This allowed the frame size to be enlarged further, which gave a better view from the window. This was an important innovation.

Another significant improvement was the introduction of the double-hung sliding windows at the end of the I920s and beginning of I930s. This allowed both the lower and upper sash to be opened at the same time and also improved the ventilation of the building.

The most commonly used kind of sash is made of slow-growing deal (pine) but oak was used in the more prestigious buildings and in earlier examples. A parting bead separates the two sashes and it is important that this is well maintained to prevent rattles and draughts. The sash pulleys, idler wheels and sash rollers are essential to the operation of the window.

2. Energy efficiency

As larger and clearer sheets of glass were made available, sash windows started replacing hinged casements. They were glazed with plate glass placed within timber frames with rebates and secured with glazing sprigs and putty on both sides to make them watertight. This type of glazing gradually replaced the use of leaded lights.

Sashes were introduced, which resulted in a greater demand for ironmongery. The most basic fittings were brass pulleys (and later cast-iron) weights and stoppers for sashes, shutter hinges and handles and various fasteners used to fix the sashes. These were usually decorated with designs, inscriptions, and engravings to identify the maker.

Sash windows can be extremely energy efficient when they are maintained regularly. Without this maintenance, they can become draughty. Putty and paint can also cause draughts. This can be fixed by making use of wood-to-timber repair tools that are proprietary.

The replacement window industry relies on the assumption that old windows are damaged and beyond economical repair, while they are able to be maintained with just a little care. Repairs can be expensive and cause a lot of disruption in the home. To avoid this homeowners often opt for a complete replacement with PVC-u windows made by one of the many «one stop shop» installation companies. They can replace all windows in a house in a single day, saving time and eliminating the need for different tradesmen to coordinate. These windows can be equipped with energy-saving’ double glazing to achieve higher energy ratings than traditional windows with sash. These double glazing cambridge-glazed units are not capable of resembling the proportions and section of sashes from old timber.

3. Security

Traditional windows can be made secure without compromising their appearance. Many types of ironmongery can be fitted with sash chains, mortice bolts and locks for sash. These can be put in place to ensure that the window is capable of being opened for ventilation or cleaning. These windows are typically discrete since they are made to be used in conjunction with sash windows. They can be used in conjunction with traditional sash-window catches that must be replaced by more robust versions (such ones with double screws) or spring-loaded levers to minimize the risk of them being opened by hammering.

Sash-window frames are typically constructed from oak or slow-grown deal. When glazing bars have survived they should be kept and, if possible, the timber of the cill should be replaced with identical wood. Many PVC-U companies offer a one-stop shop installation service. They can take out and replace windows on a complete home in a single day, without involving other tradespeople.

4. Ventilation

When sash windows were first introduced in the 17th century they allowed a significant amount of light to flood into buildings. In the 18th century, they were adapted so that even more light could be let into the rooms. Larger glazing panes were also created. The result was a much lighter appearance, and windows that had a higher degree of elegance than before.

Sash windows were introduced that required a brand new type of ironmongery. Early pulleys could be made out of wood. Later Victorian ones were made of brass or a mixture of wood and leaded. There were also different types of shutter hinges and knobs. The ironmongery pieces need to be maintained and cleaned to appreciate their beautiful design.

Timber windows require regular maintenance to keep them in good order. Inattention to maintenance routinely could lead to:

Sashes that don’t slide effortlessly.

holes in the frame allow water, which can cause damage and decay.

break down of the putty and allow water penetration, which could lead to decay of the frame and cill.

In the I920s and I930s, steel Casement window crank Repair windows grew in popularity because they were strong slim and affordable and also matched the fashion for healthy living. Studies have shown that softwood sash window are as efficient as PVC-u windows, and may even be more attractive.

The window replacement industry has done a great job convincing homeowners that their old windows were decayed drafty, noisy and beyond repair. Many old windows made of timber can be fixed and utilized for a longer period with minor repairs.

5. Maintenance

The traditional sash windows require regular maintenance and inspection. If you do not maintain your window’s sash, it could cause the sash cords breaking, and the glazing bars wearing out excessively. It can also cause paint and putty become damaged. The removal of sashes may also result in structural movements within the frame, which can cause the sash to not close properly. The sash can also be stuck in the open position, allowing the water and drafts to enter the property.

Moisture penetration is the most common cause of damage to timber windows. This can be avoided by regular repairs by thorough painting and eliminating the cause of dampness. The paint can be removed to reveal the soft, rotting wood. Any rotten timber sections should be cut off and the affected part carefully scarfed or pieced in using replacements made from the same type of timber as the ones remaining. This method of repair maximizes the amount of original fabric left, and is among the least invasive ways of treating decay caused by timber.

The use of a resin-based wood consolidant is a different option to traditional sanding and staining. It is brushed on the surface of the wood to stabilize it and protect it from further damage. It is particularly beneficial for the treatment of pulleys and sash cords which help prevent the breakage.

It is crucial that any old ironmongery such as sash stay and latches are retained and rehabilitated instead of being replaced. It is difficult to replace these items without compromising their original design. It is recommended that the use of modern aluminum fittings like chain stays and sash lifts should be avoided if feasible as they could cause corrosion and deterioration to timber frames and sashes.