C O N T E X T 1 2 5 : J U LY 2 0 1 2 11 Caroe& Partners Architects Wells | London | Cardiff | Ledbury Tel 01749 677561 | info@caroe.co.uk | www.caroe.co.uk house where the dining room ceiling had developed serious cracking. The immediate conclusion was that there was something wrong with the beam supporting the upper floor; probably it had been attacked by deathwatch beetle. Inspection showed that the problemwas the very large chandelier, which proved not to be fixed to a beam, as we had imagined, but simply screwed into the plaster. Why it had not collapsed when it was first installed was far from clear. Do not assume that the wall downstairs is directly below the one upstairs. It probably is, but equally it may not be. Does the wall have a foundation that would meet current regulations (even remotely)? Probably not, but does this matter if the building is surviving undamaged? Inspection will help solve this conundrum. Always look for the expected: rotten timber where it is built into external walls; lack of bracing where walls or timber frames lean; and lack of foundations where walls crack. But also look for the unexpected: decay at the centre of a beam where all should be well; old water courses under buildings allowing otherwise sound foundations to fail; voids in apparently solid walls; and snap headers inVictorian brick walls that appear to be better bonded than they really are.Timber is a material that can often catch us out by appearing to be in fine fettle when really the side up against a wall or hidden by boarding hides decay. One church roof I examined proved to have quite serious decay when the boards were lifted. Even when I knew this, the normally exposed surfaces were in excellent condition. I was left wondering howmany other roofs that I had pronounced as good actually had hidden problems. Try using a decay-detecting drill to check out suspect timber members. These drills bore holes just 1mm in diameter 200mm deep into timber to check for decayed areas, causing minimal damage and can be hired with an expert operator for relatively modest sums. Poking wood with a penknife or a screwdriver really is not good enough. Lessons 1. Take care on ladders and in dangerous situations: good conservation professionals are hard to come by. Context June 1997 has an article on safety. 2. It is often much easier to develop a repair scheme than it is to work out how that scheme can be installed safely. Think about temporary works when developing conservation schemes. 3. Consider structural monitoring if you or others are in doubt as to the degree or direction of structural movement. 4. When advising on repairs, bear in mind the safety of those carrying out the work and the stability of the structure, and take proper advice from someone experienced in such matters. Consider using the services of a conservation engineer. 5.Just how good is that beam you have just looked at? Would it benefit from a proper inspection with micro-drilling? Ian Hume teaches conservation engineering. He was chief engineer at English Heritage from 1987–97 and a conservation engineering consultant until 2008.
RkJQdWJsaXNoZXIy MjgyMjA=