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Windows and doors of historical buildings

Windows and doors of historical buildings

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Each type of building has its own set of doors and windows that are characteristic to a particular era or architectural style. When restoring or replacing windows, it is important to consider the technical condition and type of existing windows: their size, frame width, number of frames (double frame, single frame), square distribution, handing, details characteristic of the frame and jambs as well as their material and colour.

Windows and doors that look distinct from the original ones or have a modern or simplified design alter the previous appearance of the exterior and stand out from the rest of the building.

You must follow these guidelines when restoring windows and doors:
  • At first, determine whether these windows and doors are original or have been replaced.
  • It may seem that the old windows are in bad condition, but their appearance can often be deceiving. In the old days, wood used for construction was chosen more carefully and handmade windows were made of higher quality wood. We advise contacting an expert or asking a restorer to estimate whether and to what extent the original windows and doors can be restored.
  • Even old windows and doors can be insulated and made more energy efficient. Windows can be sealed and the inner frame replaced with a modern sealed unit. Doors can also be sealed and a double door can be installed.
  • Double frame windows are generally more suitable for an old, historical building. A single frame window with triple-glazed glass is very heavy and requires thick frames and beams that are strong enough to hold the glass. These windows also have less glass area than old, historical windows. The technology of triple-glazed windows does not allow the building of narrow frames, profiles, sloped frames, fine and special-shaped glazing bars passing through the glass, cracks and other details that are characteristic to the windows of a historical building. Triple-glazed windows look similar to plastic windows from the outside, which is why they are not architecturally suitable for historical buildings. Depending on their appearance and special solution, triple-glazed windows with little frame division may be suitable for functionalist buildings or post-war individual residences. Replacing a double frame window with a single frame window increases the risk of a thermal bridge.
  • Windows have not always been white. The window jambs may have also been in a contrasting colour. In the case of wooden houses, it is important to preserve the historical character of their windows. This can be achieved by adding details that are appropriate for the building’s type or era: a decorative trim, water stains or upper and lower cornices.
  • In old buildings, the glass area of opening and non-opening windows must remain the same (except for ventilation windows). Frames with different sized panes stand out immediately as they are not characteristic to old buildings.
  • When insulating a facade, make sure that the position of the windows does not change in relation to the facade. The windows of wood facades tend to be flush with the cladding. The depth of the window recess can be greater for rendered and stone facades, depending on the building’s historical design. It is important to avoid deep recessed windows that can form when insulating a building. Recessed windows are not characteristic to historical buildings and alter their exterior in a negative way.
  • We advise using an oil-based paint that has great coverage to paint window frames, such as traditional linseed oil paint with a zinc additive. Oil-based paint adheres well to wooden details and is easy to maintain, clean and repaint. Additionally, the consumption of oil-based paint is lower and it lasts longer than modern synthetic paints. It is much more durable on window frames because it is permeable and allows moisture to pass through to the surface. As the paint wears, it slowly peels off the wood in small flakes that look similar to crocodile skin. After the previous paint layer has been cleaned, it can be repainted (it is not necessary to peel off the previous layer).
  • Changing the size and location of windows and doors is considered a structural change that requires a coordinated construction project. Generally, it is not allowed to remove log infills. The door jambs should be extended, if necessary. If you are sealing off basement windows, it is considered a reconstruction activity. Before closing off the windows, you must mark their historical position with a window recess or a blind window.
  • Windows and front doors that are made from unsuitable material (plastic, metal) or do not fit the building’s exterior should be replaced with wooden ones that follow the architectural style of the respective construction project or building type. Unsuitable windows must also be replaced if the building is undergoing comprehensive reconstruction (for example, if the building is being insulated).
  • Large floor-to-ceiling windows should be avoided when reconstructing historical buildings. We advise installing balcony and terrace doors that match the architecture and type of building and have wooden panelling at the bottom.
  • The possibility of installing rooflights is determined on a case-by-case basis. In terms of the building’s appearance, it would be best if the rooflights were facing the yard. Since rooflights are modern structures that might overburden the roof, they can only be installed in a row.
  • The windows of the attic and dormers should be smaller and have smaller panes than the windows of the main floor.
  • The reconstruction project of a valuable building or a building located in a scenic district must include a separate section for windows and doors. If necessary (for example when the windows are replaced), the construction project must also include detailed sketches and horizontal and vertical cross-sections of windows and doors as well as their detailed specification.
  • Old windows and doors that are about to be replaced should be recycled. Historical details that have been made from traditional material can be reused in other buildings or fulfil another function in the original building (as an interior window or furniture part).
  • Find out why you should prefer a wood window to a plastic window
  • Read more about the history and repair of windows
  • Read more about historical doors and how to restore them.



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Joonis: Tallinna maja avatäidete detailid. Kultuuriväärtuste Amet, 2010.

Last modified 30.04.2024