Woodworm in Roof Timbers: What to Do
Check loft rafters and roof timbers for woodworm, learn why roof wood is high risk, how bats affect work and how treatment and repair usually go in a UK home.
Roof timbers hold up the whole house, so woodworm there deserves care. The loft is also cool, quiet and rarely visited, which suits the beetle. This guide shows how to check, what to look for and how treatment works.
How to check the loft
Choose a dry day and take a torch. Stay on the joists or on boards, because the ceiling below will not take your weight. Take care, since a slip can cause an injury. Wear a mask, since loft dust is unpleasant.
Look at rafters, purlins and the wall plates where the roof meets the walls. Check for:
- Small round holes
- Pale dust on the timber or on the insulation
- Soft wood that a screwdriver sinks into
- Damp stains from leaks
Large oval holes in softwood suggest the house longhorn beetle, which is rare and serious.
Why the roof is high risk
The roof carries load, so weak timber matters more here. Roofs also trap damp when tiles slip or flashing fails. Damp wood is easier for larvae to eat, so a small leak can invite a big problem. However, a quick repair often stops it.
Loft insulation can make the timber colder and damper too. Keep the roof space ventilated, and do not block the eaves.
Bats
All UK bats and their roosts are protected by law. If you see bats or droppings, stop and take advice before any work. Ask any specialist how they handle bat checks. The Bat Conservation Trust and the government guidance explain the rules.
How treatment works
Most roof jobs use a water-based spray on all exposed timber. Thick members may need boron paste, because paste reaches deeper. In severe cases, a team may use fogging.
Weak rafters or wall plates need timber repair. A structural engineer may advise on load-bearing work, because safety comes first.
What it costs
Published guides put a loft at about £500 to £800 outside London, and MyJobQuote gives £800 to £1,000 for a 25m² loft. Access, severity and repairs change the price, while London costs more. See the cost guide for the sources.
After treatment
Fix the leak that caused the damp, and keep the roof ventilated. Check the timber each spring. Read how long treatment lasts for what to expect.
If you find signs of woodworm in the loft, request a survey. You may also want to read woodworm in structural beams.
Local housing changes the risk. Read about woodworm treatment in London and woodworm treatment in Manchester to see what affects homes in each area.
To go deeper, read about the house longhorn beetle and the structural timber repair, because the right method depends on the beetle.