Structural Timber Repair & Replacement
When beetle damage has weakened a beam, the wood needs repair as well as treatment.
- Repair options: splice, resin or replace
- Treatment stops the beetle, repair restores strength
- Load-bearing work may need an engineer
What timber repair does
Killing the beetle does not put back wood that has been eaten. If a joist or rafter has lost strength, it needs repair. The aim is to restore the load path with sound timber.
Small areas can often be cut out and filled. Larger sections may need a new length spliced in. In severe cases, the whole member is replaced.
How a repair runs
Repair work follows a clear order, because safety comes first.
- 1
Assess the damage
A surveyor probes the wood and marks weak areas. For load-bearing timber they may ask a structural engineer to advise, because safety comes first.
- 2
Support and cut out
The team props the structure and removes weak wood. They keep sound wood wherever they can.
- 3
Repair and treat
New timber, resin or a splice restores strength. All new and old wood is then treated against beetle.
What to weigh up
Every method has trade-offs. Weigh them against your own timber, because no method suits every case.
Splice
A new section joins the sound part of a joist. Plates or bolts carry the load, so the repair stays strong.
Resin repair
Resin fills lost areas and bonds with sound wood. It suits historic timber, since you keep the original.
Replacement
A new member takes the place of a failed one. It is the best answer when little sound wood remains, although it costs more.
Limits to know
Structural changes may need building control approval. Ask your specialist to explain what applies.
When this method is the right choice
Use this list to check the fit. A mismatch wastes money, since each method has limits.
- Joists or rafters that feel soft, flex or crumble
- Beam ends weakened by damp and beetle together
- Cases where a survey finds structural loss
Help in your area
This applies across the UK, but housing differs by city. For local detail, read about woodworm treatment in London and woodworm treatment in Manchester, because older streets hold more old timber.
Timber Repair: your questions
Does treated timber need repair?
Only if it has lost strength. Many treated timbers stay sound. A surveyor will probe the wood to decide.
Do I need an engineer?
For load-bearing members, often yes. The surveyor will say if you need one.
Do I need building control approval?
Some structural work needs approval. Check with your local building control team before work starts.
How much does repair cost?
DampHub estimates £200 to £500 for small repairs and £1,000 or more for large beams. Read the cost guide for sources.
Helpful next steps
Not sure which method you need?
Request a survey, because the right method depends on the beetle and the timber. A local specialist will call you to arrange a visit.