The Top Cambridge Window Gurus Do 3 Things
Maintaining Timber Windows
A well-maintained wooden window is a crucial element of a building that is historic. It reflects in varying degree the technology and materials of the time period it was constructed, the architectural style and craftsmanship.
When possible, repairs should be made on-site. Proprietary resin-based repair systems can be used to fix the worst areas of decay without removing the entire window.
Durability
The windows made of wood in many historical buildings were built to last for hundreds of years. However, they do need to be maintained to ensure that they look good and operating properly. doors and windows cambridge -asked maintenance tasks include repairs to sash cords and re-tightening the sash pulleys and painting. There is a growing need to upgrade the timber windows to increase the efficiency of energy. This can include replacing old glazing units, repairing existing window rebates or installing new cills for improved air seal.
The deterioration of paintwork is a major problem with traditional windows. This is particularly important when sash windows are concerned, as the gaps between sashes can be extremely large. In these instances water can enter the paint film and cause rotting to the putty or wood beneath. The rotting may be further aggravated by weather conditions that are not ideal. To prevent this from happening, windows must be painted regularly with an exterior wood paint.
Areas that have been damaged must be repaired using resin-based products. This will ensure that the maximum possible amount of the original fabric remains. It is also important to limit the number of holes drilled into the frame to allow cable entry as these can let in water and cause decay.
The wall's structural movement can also lead to distortions in the frame as well as sash. This could result in the sash not fitting properly and jamming or sticking into the opening, or breaking glass. Often this can be corrected by fitting new sash boxes made from slow grown deal (pine) or oak. The cill needs to be constructed of a strong hardwood like oak, to avoid differential movement between new and old work.
There are several companies that make Boston pattern wooden sash that fit in with the majority of openings. They are available in a range of sizes and finishes to meet the needs of the modern homeowner. In conjunction with quadruple draught strip and improved thermal insulation, these new sash options can make significant improvements to the energy efficiency of a house.
Aesthetics
Many old timber windows have a high aesthetic value because they typically illustrate, in some way the materials and techniques and architectural style of the time in which they originate. They also may have a significant historical significance in their individual cases. This is particularly true of early unglazed window openings in timber framed buildings where the great majority were simply a series of openings within the frame, which were divided horizontally into mullions and vertical wood or iron bars to deter intruders.
Traditional timber window joinery can be a stunning feature of a building and it is important to keep it looking good. As soon as you notice any decay caused by moisture penetration it is essential to stop it. This is best done by applying a thorough coat of paint, particularly in areas that have already suffered damage or degradation. It is advisable to use paints designed to be used as part of the system (primer as well as undercoat, finish and primer) and follow the manufacturer's guidelines in terms of preparation and the amount of coats required at each stage.
Wet rot is a typical problem for older timber windows. The best way to stop it becoming a problem is to take out 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 with a slow-growing deal (pine) and, wherever possible using the same species as which is being removed to avoid shifting between the new and old timbers.
Glass became cheaper and more abundant during the late medieval period and into the 17th century. In the process, the openings for glazed windows on timber-framed houses became more complex with moulded mullions, wooden tracery and deep projecting cills. The glazing was increasingly laid within rebated frames and pinned in with 'glazing sprigs' rather than being inserted into lead cames. This method of glazing not only makes the windows less likely to leak and break, but also allows wider sheets of clearer glass to be utilized than would have been possible otherwise without the use of leaded lights.
Energy efficiency
Traditional timber windows are energy efficient due to their thickness, multilayer construction and care for detail. They also feature large glass areas as well as deep projection cills which reduce air infiltration. The windows can be made to improve their energy efficiency by draught-proofing and secondary glazing. However, it is important to keep in mind that these measures must be considered in relation to the overall quality and appearance of the original window.
So, retaining existing historic windows that require repair rather than replacing them is sensible particularly when thermal improvements can be achieved inexpensively with simple repairs and improvements. Older windows are usually of historical significance, since they reflect a variety of technological advancement and changes in architectural taste. Most people think that these windows will have to be replaced in the near future. However, most can still provide service for 150,200, and even 250 years with proper maintenance.
It is important to recognise that the decay issues that are typical of timber windows can be prevented by regular maintenance and prompt repairs. It is also important to spot damp issues and fix them quickly to avoid major damage. The early deterioration of paint could be a problem as it allows moisture to get into the wood, which can cause wet rot. The damage is usually not evident until the paintwork becomes wavy or cracked however, it can cause serious structural damage and can lead to further decay.
A good paint will stop moisture from entering the paint. To prevent mould and condensation, it is important to keep the paintwork as clean as it can be. Modern synthetic paints could be a problem because they are usually designed to be water-resistant and this may lead to the formation of mildew inside the window frame.
The majority of older windows were manufactured from timber containing the majority of sapwood. These timbers can deteriorate quickly when exposed to rain, however they can be protected with a thorough preservation treatment before use. It is also important to ensure that the type of timber used is well-suited to the climate and site conditions, as these factors affect the durability of the joinery. Local window manufacturers provide a wide range of sash timbers that can be customized to fit historic openings. They are available in the standard Boston pattern or in custom sizes that can be adapted to historical buildings.
Maintenance
Regular inspection, careful redecoration, and prompt repairs can extend the life of wooden windows. The major cause of decay is the penetration of moisture through deteriorated paint or putty. This can be avoided by using a quality wood preservative and thoroughly painting the wood.
It is essential that repairs to old sash or casement windows are well executed, and carried out without causing any disturbance. Repairs can be made to the majority of traditional wooden window designs without taking the frame off. This should be done as often as is feasible. Remove any peeling or loose paint and lightly sand the surface to improve the "key" of the surface. This will enable the new coating to stick better. It is important to avoid removing old paint layers, which may have historical significance.
If a piece of timber has become rotten the best course of action is to remove the rotted material and replace it with spliced-in timber inserts that are shaped to fit the existing profiles. The inserted wood should also be treated with a wood preservative, and the junction between the timber cill and the masonry sub-cill should be sealed.
Replacement of windows made of traditional PVC-u may be an attractive option, especially when the installer offers an "all-in-one" installation service that can handle removal and replacement in the span of a day. It is vital that the installer of replacement windows has a complete understanding of the construction and history of traditional timber frames. This will allow them to make the right recommendations for energy efficiency improvements and other technical improvements that will not harm the historic character of a building. Those who provide replacement windows should be registered under a Competent Persons Scheme, such as FENSA. This will ensure that replacement windows are approved in accordance with Building Regulations as a suitable option. A skilled carpenter can install PVC-u Windows that are sympathetic to original building's character. This is especially true when the windows are located within conservation areas or listed buildings.