Five Cambridge Window Lessons From The Professionals

Maintaining Timber Windows

A well-maintained wooden window is a crucial component of a historical building. It reflects in varying degree the materials and techniques of the time period it was made, the design and craftsmanship.

If repairs are possible to existing windows should be carried out in-situ. Proprietary resin-based repair systems can be used to repair the worst areas of decay without having to remove the entire window.

Durability

The windows made of timber in many old buildings were made to last for a long time. However, they do need to be maintained to keep them looking good and functioning correctly. Maintenance tasks include repairs to sash cables and retightening pulleys on sash, and painting. There is a growing need to upgrade timber windows to increase the efficiency of energy. This may mean replacing old glazing units, repairing the window rebates that are in place or putting in new cills that allow for better air sealing.

A key problem with traditional windows is damage caused by the corrosion of the paintwork. This is particularly important when sash windows are concerned because the gaps between sashes may be quite large. In these situations water may get through the paint film and cause rotting of the putty as well as the wood underneath. The rotting may be further aggravated by weather conditions that are not ideal. To prevent this windows from becoming rotten, they must be painted regularly using an exterior wood paint that is suitable.

In addition to repainting, corroded areas should be repaired with an adhesive-based repair product. This will ensure that the best possible amount of the original fabric remains. It is also important to minimise the number of holes drilled into the frame for cable entry, as they could allow water in and cause decay.

The structural movement of the wall could also cause distortions in the frame and sash. This can result in the sash not fitting properly and jamming or sticking to the opening and cracked glazing. Most often, this is corrected through the installation of new sash boxes that have been constructed from slow-growing deal (pine) or oak. The cill must be made from a sturdy hardwood, such as oak, to avoid the movement of new and old work.

There are several companies that produce Boston pattern wooden sash to fit into the majority of existing openings. The sash is available in a variety of sizes and finishes to suit the requirements of the modern homeowner. In conjunction with quadruple draught strip and a better thermal insulation, these new sash can make an enormous difference to the energy efficiency of your home.

Aesthetics

Many old timber frames have a great aesthetic appeal, as they display, in a certain shape, the materials, technology, and architectural style of the time they were made. They could also have significant historical value in their individual cases. This is particularly true of early unglazed windows in timber-framed buildings, where the majority were series openings in structural frames that were subdivided horizontally by mullions and vertical iron or wood bars in order to keep out intruders.

Traditional window repair specialists joinery made of timber can be a stunning aspect of a building, and is crucial to keep its appearance. It is essential that any decay caused by the penetration of moisture should be removed as soon as it is recognised. This is best accomplished by applying a thorough coat of paint, particularly in areas where there has already been damage or deterioration. It is best to use paints that are designed to be used in a set (primer undercoat and finish) and to follow the manufacturer’s recommendations for preparation and number of coats at each stage.

Wet rot is a common problem in old timber windows. The best way to stop it developing is to remove sections that are damaged or rotten immediately to stop the spread of the fungus that causes it. The replacement of rotting timber should be done with care and using slow grown deal (pine) and, if possible using the same species as that which is being removed in order to prevent shifting between the new and old timbers.

Glass became more affordable and abundant in the late medieval period and into the 17th century. As a result, glazed openings on timber-framed houses became more complicated with moulded mullions, Wooden Sliding Doors Cambridge tracery and deep projecting cills. Increasingly, the glazing was set within rebated frames and then pinned with 'glazing sprigs', rather than into lead cames. This method of glazing not only makes the windows less likely to leak and break, but also allows more clear glass sheets to be used than would have been feasible without the use of leaded lights.

Energy efficiency

Traditional timber windows have an excellent energy performance due to their thickness, multi-layer construction and very meticulous attention to detail. The large glass areas, deep projecting cills, and the large glazing areas reduce air infiltration. The windows can be modified to increase their energy efficiency with draught-proofing and secondary glazing. However it is essential to keep in mind that any such measures should be evaluated in relation to the overall quality and appearance of the window in its original form.

It is sensible to fix or upgrade historic windows rather than replace them, particularly when improvement in thermal efficiency can be achieved by simple repairs. Older windows are usually of historical significance, since they show a range in technological advancement and changes in the architectural style. The pressures to replace such windows are typically based on the assumption that windows that are old will need to be replaced in the near future, however most are still capable of providing service for 150, 200 or even 250 years if properly maintained.

It is essential to understand that the decay issues that are that are typical of windows made of timber can be avoided by thorough maintenance and swift repairs. Additionally, it is essential to spot damp penetration issues and address them swiftly to avoid major damage. Early paint deterioration could be a problem as it allows moisture to get into the wood, causing wet rot. This type of damage is typically not evident until the paintwork is damaged or wavy but it can cause severe structural damage and can lead to further decay.

A paint of good quality will prevent moisture penetration. It is also necessary to keep the paintwork spotless to avoid condensation and mould growth. Modern synthetic paints are problematic because they are often water-resistant, and can cause mildew growth in the window frame.

The majority of older windows were constructed from sapwood-rich wood. These timbers are susceptible to deterioration rapidly if exposed to wet weather, but can be protected by a thorough treatment of preservative before they are used. It is important to choose the appropriate type of wood for the site and climate, as these variables can affect the durability of the joinery. Local window manufacturers produce a variety of timber sash that can be adapted to fit specific historic openings. They can be constructed to the standard Boston pattern dimensions or to specific dimensions that are compatible with the architectural style of historic buildings.

Maintenance

Regular inspection as well as careful redecoration and quick repairs can prolong the lifespan of windows made of timber. The main cause of decay is moisture penetration through the deteriorated paint and putty. This can be prevented by using a quality wood preservative and thoroughly painting the wood.

Repairs to sash windows that are old and casement window frames should be done with care and minimal disruption. A lot of traditional wooden window designs can be repaired without dismantling the frame, and this option should be used whenever it is possible. Loose or peeling paint should be removed carefully and sanded lightly to increase the 'key' of the surface and facilitate an improved adhesion of the new coating. Be careful to avoid stripping paint layers that may have historic value and if they are present, it is recommended that a paint analysis be carried out.

If a piece of wood is decayed the best option is to remove it and replace it with timber inserts that are shaped to match existing profiles. The wood that is inserted should be treated with a wood preservative, and the junction between the cill for timber and the masonry sub-cill should be sealed.

Replacement of traditional windows using PVC-u may be a tempting option, especially when the installer offers a 'one stop shop' installation that takes care of both removal and replacement within the span of a day. It is, however, essential that the person installing replacement windows has a full knowledge of the structure and history of traditional wooden windows cambridge frames. This will enable them to make the appropriate suggestions for energy efficiency improvements and other technological advancements that won't harm the character of a building that is historic. Those providing replacement windows should be registered with a Competent Persons Scheme like FENSA. This will ensure that the replacement windows are approved as a suitable option under Building Regulations. A skilled carpenter is able to install PVC-u windows that are suited to the original character of the building. This is especially relevant when windows are in conservation areas or listed buildings.