East Anglia is fortunate in having a wealth of timber-framed buildings, many of which, like the Guildhall, were built with an exuberance of carving to display the carpenter’s skills as well as the owner’s wealth. These timbers were meant to be seen, while others were covered by a skin of lime render.
To protect the wood from the elements, exposed timber frames, especially in East Anglia, were in later centuries painted with a ‘wash’ of lime that acts as a preservative against pollutants and other destructive elements in the atmosphere.
The lime is ingrained into the beams, preventing the penetration of moisture while allowing the wood to breathe – and bugs definitely don’t like it! Two or three coats are applied, after which any excess is brushed off.
We lime-wash the Guildhall every five years or so, and in due course the weather removes the lime, showing the weathered oak as a beautiful silver-grey.
Using oil-based paints, or darkening the timbers with black emulsion, is a fashion only dating from Victorian times, and can in some cases be associated with the decay of the wood. This wouldn't be consistent with our conservation principles, so for this reason we favour limewash over modern paint systems.
We don't have a blanket policy with regard to timber-framed buildings, but we treat each on its own merit.