The short answer
Repairing damaged cladding usually means removing and replacing the affected boards rather than the whole wall, provided the battens and structure behind are sound. The steps are to find the cause (impact, rot, movement or a water leak), remove the damaged board by releasing its fixings or clips, check and dry the cavity and battens behind, then fit a matching replacement with corrosion-resistant fixings and reseal the junctions. Minor splits in timber can sometimes be filled and re-coated; cracked fibre cement or buckled composite usually needs board replacement. The key is to repair the reason for the damage — often trapped water or a failed junction — not just the visible board, or the problem returns.
Most cladding damage is local and fixable without replacing the whole elevation. The sections below cover diagnosing the cause, the repair method, and when a repair turns into a bigger job.
Repairing cladding
- First stepfind the cause of failure
- Usual fixswap the affected board(s)
- Check behindbattens, cavity, drainage
- Fixingscorrosion-resistant only
- Bigger job ifbattens or structure decayed
Diagnose before you repair
The most important step happens before any board comes off: work out why it failed. Common causes are:
- Impact — a knock, ladder or debris cracking a board; often a clean local repair.
- Rot in timber — usually from trapped water at a junction, splashback at the base, or a blocked cavity.
- Movement — buckled or lifted composite from missing expansion gaps, or cupped timber.
- Fixing failure — corroded or pulled fixings letting boards lift.
- Water ingress behind the cladding from a failed flashing, sill or sealant.
If you only replace the visible board without fixing the cause — a leak, a blocked vent, missing expansion gaps — the new board will fail the same way. For widespread rot or movement, get the underlying issue assessed first.
Replacing a damaged board
For a localised repair where the structure behind is sound, the typical sequence is:
- Release the board — remove face fixings, or unclip secret-fixed and tongue-and-groove boards, working carefully to avoid damaging neighbours.
- Inspect behind — check the battens, breather membrane and cavity for damp, decay or debris; dry out and replace any rotten batten or damaged membrane.
- Cut the replacement to match length and profile, ideally from the same product range and batch so colour and section match.
- Fix it with corrosion-resistant fixings or the correct clips, leaving any specified expansion gaps.
- Reseal and finish — renew sealant at junctions and, on timber, treat cut ends and re-coat to match.
| Damage | Typical repair | Watch for |
|---|---|---|
| Cracked board (impact) | swap single board | matching profile/colour |
| Rotten timber | replace board + battens | the water source |
| Buckled composite | re-set with expansion gaps | missing gaps elsewhere |
| Lifted / loose board | renew fixings | corroded fixings nearby |
| Minor timber split | fill and re-coat | water entering split |
Indicative guidance; match repairs to the specific product and its fitting instructions.
Matching and finishing the repair
A repair that stands out is a poor repair. Try to source the same product, profile and colour reference, and keep records of the original specification so future repairs match too. New timber boards will be lighter than weathered neighbours and may need staining or time to blend; on composite, a new board may be brighter until it settles. Treat all cut ends on timber with preservative or end-grain sealer, because exposed end grain is where water enters fastest. Renew sealant and flashings at the repaired junctions rather than reusing tired ones, and re-coat timber to protect the new surface.
When repair becomes replacement
Local repairs work when the support behind is sound. The job grows when the battens, membrane or structure behind the cladding have decayed, when damage is widespread across an elevation, or when the same fault keeps recurring because the cavity or detailing was wrong from the start. In those cases, re-cladding a whole elevation — with corrected ventilation, drainage and detailing — can be more sensible than chasing repairs. If a cladding system is also tied to fire performance on a larger or multi-storey building, any significant repair or alteration should be checked against the building's fire strategy and, where needed, with building control or a competent professional before work proceeds.
Frequently asked questions
Can you replace just one cladding board?
Often yes. If the battens and structure behind are sound, a single damaged board can usually be released and swapped for a matching one. The important step is finding and fixing why it failed — impact, rot or movement — so the replacement does not fail the same way.
How do you repair rotten timber cladding?
Remove the rotten board, find and stop the water source behind it, dry out and replace any decayed batten or membrane, then fit a matching new board with corrosion-resistant fixings. Treat cut ends with preservative and re-coat. Widespread rot usually means a detailing or ventilation fault to correct.
Will a repaired cladding board match the rest?
New timber is lighter than weathered boards and may need staining or time to blend; new composite can look brighter until it settles. Sourcing the same product and colour reference helps, which is why keeping a record of the original specification is worth doing.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.