The most useful tools in any timber surveyor’s armoury are a torch, a screwdriver and keen eyesight. When surveying for timber defects, signs like previous water ingress, dampness or poor ventilation often lead straight to the problems such as wet rot, death watch beetle or dry rot. Standard joist ends, wall plates and lintels can be tested by merely poking with a screwdriver or tapping with a hammer. But what about large section timbers like trusses, tie beams, bressumers and such? These may be several hundred millimetres thick, and the parts of the timber most at risk may be inaccessible, buried in masonry or behind period features – checking these could cause unacceptable damage. This is where micro-drilling comes in…
The term micro-drilling is actually a misnomer, because our Sibtec digital micro-probe doesn’t actually have a drill bit to penetrate the timber. The micro-drilling is actually done by a 1.5MM thick steel spatula which spins at 7000rpm and under gentle pressure penetrates the fibres to depths up to 1000mm – there’s no drill dust, and nothing to see but a tiny entry hole less than 2mm wide.
The Sibtec drill control software measures how far the probe has penetrated the timber and checks every 0.1mm to record the number of probe rotations and the force applied, (in newtons). This information is downloaded into a spread sheet and the ‘hardness’ of the timber is visually displayed as a graph with the ‘X’ axis showing the depth achieved and the ‘Y’ axis showing rotations and force.
This non-destructive timber testing is combined with site information to produce detailed reports so that conservators, structural engineers, architects and property developers know in advance which timbers, if any, need structural repairs. This is why micro-drilling is so popular with those responsible for listed and period properties.
Our non-destructive timber surveys are available across the North of England from our base in Yorkshire, covering areas such as Leeds, Bradford, Wakefield, York, Sheffield and Harrogate.
We’re fully qualified, CSRT trained via the PCA and Sibtec Technology – the manufacturers of these remarkable testing machines. Micro drilling urveys can include identification of rot and insect infestation species and we can prepare repair specifications and treatment for dry rot, woodworm and wet rot repairs by our own qualified technicians.
We also offer a service to identify timber species to take the guesswork out of timber identification. Want to know whether that beam is oak or not? Send us a small sample and we’ll soon tell you!
Call Bryan Hindle CSRT CSSW on 0800 591541, for further information on micro drilling or to book a timber survey.