Windows

The sizes of openings for windows changed as the materials and styles of casements changed. Smaller, squarer windows are a reasonable indication of age, as windows generally evolved to become larger and more elongated. Early window frames in important stone-built houses would often have been constructed in stone, but a stonework frame does not necessarily indicate original age. The load paths in a timber-framed building allow for great structural flexibility, and the size and location of windows can be altered dramatically with little effect on the building.

Look for windows set near the face of the wall, as this indicates earlier construction. Windows were only generally set back following the introduction of fire regulations in the 1660s (this was slow to spread). Commonly, early windows were small and predominantly on the north faces of houses. In later centuries the windows became taller and more proportionally balanced.

The repair of windows in houses of this general period needs to be approached with great care. It is almost certain that windows visible today are not the originals and historically may be completely inaccurate. However, this does not mean that conservation principles do not apply. The choice of repair method is consequently often a fiercely debated subject.

Where timber windows are concerned, there are generally two states of disrepair that trigger a different approach. Minor timber decay and poor decoration need not condemn the window to replacement. However, expensive splice repairs, which are very hard to achieve accurately on site, may be financially impractical. This leaves the use of resin fillers. This is not approved by all conservation officers, who may regard it as a dishonest repair. However, if approved, a window can be preserved very effectively with minimal interference using site-based work. Do not underestimate the high cost of splice repairs. To achieve satisfactory long-term repairs, the components will need to be removed and repaired on a joiner's bench. Site-based repairs are extremely difficult to achieve technically and may result in premature failure and further decay. The exception to this is a simple front cill replacement, which can be removed and prepared on site if care is taken. The use of a lead cap over a cill should be viewed with caution, as water can become trapped under the lead and will rot the cill away unnoticed.

Hairline cracks in pointing around window frames can be difficult to see, but can deliver considerable amounts of water into a solid wall. Areas in corners and directly under cills are prone to this problem. Water can wick considerable distances and may cause staining some distance from the source.