The moisture contents of timber-framed external walls to occupied dwellings have been established over a four year period. These show that, for suitably designed construction, the timber sheathing and studding can remain at moisture contents below the level at which timber decay is likely.

Details of construction currently used in some buildings are, however, vulnerable. Soleplates generally tend to have rather high moisture contents and should be preservative treated as recommended in BS 5268:Part 5:1977.