Timber frames

Timber-framed infill construction was well established between 1400 and 1600, with close frame and box frame grids being most competently built. Frames are usually made up of whole panels set at regular intervals to form bays, which are then held together with floor beams and ridges (see Construction).

The cill beam is potentially the most vulnerable member of the frame, although there are other defects.

The most difficult assessment in respect of the activities of wood-boring larvae is to determine if an outbreak is still live, and how deep the infestation is. If the infestation is dormant and the structure is proved to be sound, there is little evidence to suggest that large-scale works will be cost effective or historically prudent. Keeping the timber's moisture content at the correct level will greatly decrease the risk of further attack. See Wood-boring insects.

Fungal attack is most likely to be found in areas associated with still air and moist conditions. Any smell of damp should alert the surveyor to the high risk potential of fungal attack. Further investigation should be undertaken to assess the visible evidence of fungal activity. See Fungal attack and other threats.