Maintaining Timber Windows
A well-maintained wooden window is an important element of a building that is historic. It is a representation of the materials and technologies design, craftsmanship and aesthetics of the time from which it originates.
When possible, repairs should be made on-site. Repairing the worst areas of decay can be accomplished using proprietary resin-based systems.
Durability
Timber windows were made to last for hundreds of years. But, they have to be maintained to keep them looking good and functioning correctly. The most common maintenance tasks include sash-cord repairs, re-tightening sash pulleys, and painting. The demand for upgrading timber windows in order to improve efficiency and energy efficiency is also increasing. This could include replacing old glazing units, repairing existing window rebates, or installing new cills to increase the air seal.
The corrosion of paintwork is a major issue with traditional windows. This is particularly important in the case of sash windows as the gaps between sashes may be quite large. In these situations water can get into paint film and cause rotting to the putty or wood beneath. The weather can be a factor in accelerating the rotting. To prevent this, windows should be painted regularly using an exterior wood paint that is suitable.
In addition to repainting, areas that have corroded must be repaired using a resin-based repair product. This will ensure that the highest possible amount of the original fabric is preserved. It is crucial to reduce the number of holes created into the frame to allow cable access, as these can admit moisture and cause decay.
Another significant problem with older windows is structural movement in the wall, which could cause deformation of the frame and sash. This can result in the sash not fitting properly, sticking or jamming in the opening and broken glazing. This can often be fixed by the fitting of new sash boxes made from slow grown deal (pine) or oak. The cill should be constructed of a durable hardwood, such as oak, in order to prevent any shifting between the new and older work.
To alleviate this issue to reduce the risk of this happening, there are a variety of companies that manufacture Boston pattern sash made of wood that will fit most existing openings. They are available in a range of sizes and finishes to suit the requirements of the modern homeowner. In conjunction with quadruple draught strip and better thermal insulation these new sash can make significant improvements to the energy efficiency of a house.
Aesthetics
Many old timber windows have a great aesthetic value since they usually demonstrate, in a way the materials and techniques and architectural style of the period from when they were built. They also may have a significant historic value in their in their own right. This is particularly true for early windows that were not glazed in timber-framed structures, where the majority were simply a series of openings in structural frames that were subdivided horizontally by mullions, and vertically by iron or wood bars to protect against invaders.
Traditional timber window joinery can be a stunning feature of a building and is crucial to keep its appearance. As soon as you see any signs of decay caused by water penetration it is essential to stop it. It is best to do this through thorough painting, particularly if there is damage or deterioration. It is best to choose paints that are intended to be used in a system (primer undercoat and finish) and to adhere to the manufacturer's recommendations for preparation and number coats at each stage.
The fungus that causes wet rot can spread quickly in old windows made of timber. To prevent this from happening, take out any damaged or rotten components as quickly as you can. The replacement of rotting wood should be carefully undertaken by using a slow-growing 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.
In the late medieval and 17th century periods glass became less expensive and more abundant, and the openings for glazed glass in timber-framed buildings gradually became sophisticated with wooden tracery moulded mullions, moulded mullions, and deep protruding cills. In recent years, glass was fixed to frames that were rebated with glazing sprigs rather than lead cames. This method of glazing is not just less prone to leaks but it can allow for larger and clearer sheets of glass to be used in the windows than would have been possible without the need for lead lights.
Energy efficiency
The traditional timber windows are energy efficient due to their thickness, multilayer construction and attention to detail. They also feature large glass areas as well as deep projecting cills that minimise air infiltration. With secondary glazing and draughtproofing windows can be upgraded to increase their energy efficiency. It is important to remember that these measures must be considered in relation to the overall integrity and appearance of the original windows.
As a result, retaining old windows that require repair rather than replacing them makes sense especially when their thermal improvements can be achieved cost-effectively through simple repairs and improvements. Older windows are usually of historical value, as they reflect a variety of technological advancements and changes to architectural style. The pressures to replace such windows are usually based on the assumption that old windows will need replacement in the near future, however they are capable of providing service for 150, 200 or even 250 years, if properly maintained.
It is essential to realize that decay issues in traditional timber windows are avoidable with prompt and thorough repairs. It is also essential to spot damp issues and address them promptly to avoid major damage. The early deterioration of paint is a concern because it allows moisture to penetrate into the wood, leading to wet rot. It is not uncommon for this damage to go unnoticed until paintwork begins to crack or becomes wavy. However, it could cause structural damage and lead to further decay.
A good quality paint will prevent this moisture from entering. To prevent mould and condensation it is crucial to keep the paintwork as clean as you can. Modern synthetic paints are problematic because they are water-resistant, and can cause mildew to develop within the window frame.
The majority of windows from the past were manufactured from timber containing a high proportion of sapwood. These timbers deteriorate quickly if exposed to rain, however they can be protected by a thorough preservation process prior to use. It is important to choose the right type of wood for the site and climate, as these variables can affect the longevity of the joinery. Local window manufacturers offer a wide range of sash made from timber that can be customized to fit historic openings. They can be made in the standard Boston pattern or in custom sizes that can be adapted to historical structures.
Maintenance
The lifespan of windows made of timber can be extended through regular inspections carefully redecoration, and prompt repair. The primary cause of decay is moisture intrusion through the deterioration of paint and putty. This can be avoided with thorough painting and the use of a good quality wood preservative.
Repairs to sash windows that are old and frameless casement windows should be handled with care and with the least amount of disruption. Many of the traditional designs for timber windows are repairable without removing the frame, and this method should be followed whenever feasible. Loose or peeling paint should be removed carefully and lightly sanded to improve the "key" of the surface, allowing for a better adhesion of the new coating. It is essential to avoid removing old paint layers, as they could have historical significance.
Where a section of timber has become rotten the best option is to take out the rotten material and replace it with spliced-in inserts that are shaped to match existing profiles. The inserted wood should also be treated with a wood preservative, and the junction between the timber cill and sub-cill of the masonry should be sealed.
Replacement of traditional windows using PVC-u can be an attractive option, especially when the installer offers a 'one stop shop' installation that handles removal and replacement within the span of a day. It is vital that the installer of replacement windows has a complete knowledge of the structure and history of traditional wooden frames. This will enable them to make the right recommendations for energy-efficiency improvements and other technological improvements that don't alter the appearance of an historic building. Anyone who installs replacement windows must be registered under a Competent Persons Scheme such as FENSA. This will ensure that replacement windows are deemed to be approved in accordance with Building Regulations as a suitable alternative. It is, of course, possible for an experienced and skilled carpenter to install PVC-u windows that match the style double glazing company cambridge of the building originally. This is especially true when the windows are located in listed buildings and conservation areas.