The short answer
Roof timbers are checked once the old covering and battens are stripped, and only those that fail the check are replaced. Battens are normally renewed with the covering. Rafters, wall plates and rafter feet are repaired or doubled up where rot or movement shows. Since the extent is hidden beforehand, timber work gets its own rate in the quote, agreed before any extra work is done.
Why the timbers cannot be judged until the roof is stripped
From the street or the loft hatch you see part of the timbers, and a damp stain on one rafter tells you little about its neighbour. Our survey photographs record sagging, daylight and staining, but a rafter foot hidden under a wall plate, or a batten rotted behind the underlay, only shows when the roof is open.
That is normal for the trade, and the sensible response is to agree the method first. We write down what will be checked, who decides and how extra work is priced, so the first sight of a rotten timber is not also the first conversation about money.
The checks are the same whatever the covering. Slate, clay, concrete or stone, the structure below is a timber frame that has either stayed dry for most of its life or has not. How the roof came to fail in the first place matters, and our answer on why roofs fail covers the usual causes. For the wider service, see roof replacement.
How we check rafters, battens and wall plates
With the covering and old battens off, the timbers are examined part by part. Battens are the thin horizontal strips that carry the tiles or slates. Rafters are the sloping timbers beneath them. The wall plate is the timber laid on the masonry that the rafters bear on, passing the load into the wall.
What we look for
- soft or crumbling timber, tested by pressing an awl into the surface
- rafter feet that have rotted where a leaking gutter or failed lead kept them wet
- sag or twist along a rafter, which can mean it is overloaded or cracked
- old insect holes, with a check on whether they are active
- ridge and hip boards that have split or dropped
- a purlin (a horizontal beam supporting the rafters) that has shifted on its bearing
Timber that is dry, firm and straight stays. Damaged timber is marked, photographed and shown to you before anything is cut out.
The common repairs, from battens to rafter feet
Most timber work on a re-roof is small and repetitive, and cheap beside the rest of the job. That is exactly why it should never be a surprise.
Battens are almost always renewed with the covering, since old ones carry nail holes from the last roof. Our answer on battens and underlay on a re-roof covers the choices.
Where a rafter foot has rotted, the usual repair is to cut out the damaged length and fix a new timber alongside it, known as sistering, so it bears properly on the wall plate. A wall plate gone soft in places can be partly replaced. A rafter cracked along its length can be strengthened by bolting a new one beside it, and a split ridge board is swapped. Any structural alteration, as opposed to like-for-like repair, is a matter for your building control body, and we raise it with you first.
Replacing a few rafter ends is ordinary repair work. Changing how the frame carries load is different, and it needs a structural check.
How timber work is priced
Rafter and wall plate repairs vary too widely for one range, because the work runs from a single batten to a whole slope. The national guide covers the whole job instead: MyBuilder's 2026 new roof cost guide gives £5,000 to £12,000 as typical for a full re-roof, with labour at £50 to £130 per m².
In our quote, timber shows up twice. Battens are included in the materials and labour, since every re-roof needs them. Structural timber (rafters, plates and boards) cannot be known in advance, so after the survey we set a day rate or a rate per repair against it, and the stripped roof then shows how much is used. You hear about each repair as it is found, with photographs, and any extra is agreed before it is carried out.
Fixing the rate for extra timbers before work begins is the best protection against argument. Ask any roofer for it, not only us.
When the timbers change what the roof can carry
The frame decides which coverings it can carry. A change that makes the covering 15 per cent or more heavier brings in approval, the Planning Portal says; Approved Document A says more than 15%. That rule has its own answer, changing to a heavier roof covering, so here the point is narrower: an old frame that has sagged under stone for generations may be past strengthening, while a sound, plain one may take something lighter without fuss.
The reverse applies too. A lighter metal covering on an old frame lowers the load but changes fixings and ventilation, as metal roofs on houses explains for zinc and steel.
What happens when the news is bad
Occasionally a stripped roof shows that large parts of the frame have failed, perhaps from years of a hidden leak or a soaked wall plate. We stop, photograph it and talk to you before doing anything else. The options are usually a larger repair, work by slope in stages, or an engineer's opinion where the frame has moved. Where the structure may be affected, the Planning Portal advises that an engineer or a surveyor sees the frame before work starts.
Our 10-year workmanship guarantee, given in writing, applies to our own work, new timbers and their fixings included. What guarantee comes with a new roof explains where it stops.