House Longhorn Beetle
What is it?
The House Longhorn Beetle (Hylotrupes bajulus) is rarely found outside of SE England and can cause significant structural weakening and even collapse of timbers. Often found in roof timbers, it only infects softwoods and burrows through the sapwood extensively.
How to spot it
The adult exit holes are oval in shape, measuring 5mm (<¼in) x 9mm (⅜in) and are filled with a bore dust, or 'frass' of sausage-shaped pellets. When the wood is split open, the internal damage will be far more extensive that the external appearance suggests, with large flattened tunnels that often mere with one another.
How to fix it
Woodworm treatment has two phases:
Any structurally weakened wood should be cut out and removed, and replaced with new timbers treated with preservative. If this woodwork was load-bearing (joist or roof truss) it should be replaced with new timbers that have been pre-treated with an effective preservative such as pressurisation, double vacuum methods or a 10-minute dip in an organic solvent preservative to satisfy the requirements of British Standard BS 5268. Remember to re-treat any cut-ends or joints.
A combined insecticide and wood preservative should be sprayed over the remaining affected area to kill off any viable eggs, larvae and adults in the wood and simultaneously fortify the remaining wood. Clean timbers first and temporarily remove and loft insulation to allow full access to joists if these are infected. Lift every 7th floorboard and cover their undersides and the joists supporting them. Cover electric cables.
Further information and useful links
- Find a Damp Proofing Specialist near you
- Find a Water Proofing Specialist near you
- Find a Wood Worm Specialist near you
- Find a Masonry Repairs Service near you
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