Devon · England
Floor joist repairs in Devon
Floor joist repairs in Devon starts with the ground. Clay shrinkage is less of a concern in Devon, so other causes such as drains, poor footings or older walls are checked first, and the buildings here are mostly cob and stone cottages, so the repair has to suit both.
Guide price from£260per joist inc VAT

- Area
- Devon
- Pricing region
- South West
- Ground
- Mostly firmer ground
- Towns listed
- 10
How do local ground conditions affect floor joist repairs in Devon?
Devon's ground is mostly older mudstones, sandstones and granite, so shrinkable-clay subsidence is less widespread than further east. Older solid-walled and cob buildings, steep sites and retaining walls are the more common structural concerns.
Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Housing stock in Devon: Cob and stone cottages, Victorian terraces in Exeter, Plymouth and Torbay, and post-war estates.
Which repair method suits a home in Devon?
Replacing joists and boards
When rot or woodworm runs through most of a floor, it is usually cheaper to replace the joists, strutting and boards together. Where joists run parallel to an outside wall, restraint straps tie the new floor back to it so the wall keeps its lateral support.
Best for: Widespread rot, or a whole floor that has dropped
Sistering a joist
A new length of treated timber, the same depth as the original, is bolted or screwed alongside the damaged joist so the two share the load. It is the quickest fix for a notched, cracked or sagging joist that is otherwise sound, usually after lifting a few boards.
Best for: Cut, cracked or sagging joists with sound ends
Sleeper walls and ventilation
Settled or damp sleeper walls are rebuilt on a sound base with a damp-proof course under new timber plates. Blocked air bricks are cleared, extra ones added where the void has dead spots, and soil or paving heaped against the outside wall is lowered.
Best for: Damp ground floor voids or joists on poor supports
What happens when we carry out floor joist repairs in Devon?
Photos and a call
Send photos of the dip or soft area, the outside wall at ground level and any air bricks. A short call about when it started, and any recent plumbing or heating work, tells us whether the problem is local or widespread.
Written quote
You get a no-obligation written quote listing which joists are sistered, spliced or replaced and any sleeper wall or ventilation work. It becomes a fixed price in writing once the repair is specified.
Repair the structure
Boards are lifted and numbered if they are going back, and rotten timber is cut out. New treated timber is fixed and checked with a level before strutting, hangers and any restraint straps go in.
Signs you may need floor joist repairs
- Floor dipping towards an outside wall or in the middle of the room
- Soft or spongy boards near outside walls, hearths or the bathroom
- Floor bouncing, or ornaments rattling, when someone walks across
- A musty smell, or fungal strands showing between the boards
How much will floor joist repairs cost in Devon?
The ranges below reflect typical South West costs for floor joist repairs, including VAT. Scaffold, access and making good can push a job to the top of the range.
| Item | Guide price | Per |
|---|---|---|
| Splicing or sistering a damaged joist | £260 – £410 | per joist |
| Whole room of joists and boards | £2,050 – £6,200 | per room |
| Sleeper wall rebuild and ventilationest. | £410 – £1,550 | per room |
Do you need approval for floor joist repairs in England?
Like-for-like repairs such as crack stitching and repointing do not usually need building control approval in England, but anything that changes or strengthens the structure, such as underpinning or rebuilding a wall, does. If the work touches a party wall, the Party Wall etc. Act 1996 may apply.
Towns in Devon we cover for floor joist repairs
Floor joist repairs in Devon: questions and answers
Is the ground in Devon prone to subsidence?
Devon's ground is mostly older mudstones, sandstones and granite, so shrinkable-clay subsidence is less widespread than further east. Older solid-walled and cob buildings, steep sites and retaining walls are the more common structural concerns. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Only an investigation on site can say why a particular building has moved.
How much will floor joist repairs cost in Devon?
On South West rates, floor joist repairs starts from about £260 per joist, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
Will my insurance pay for rotten floor joists?
Usually not, because rot, woodworm and gradual wear are standard exclusions. Damage from a sudden escape of water, or a floor that dropped through subsidence, may be treated differently. Check your policy, and tell your insurer before permanent repairs start if either applies.
What causes rot in floor joists?
Damp causes almost all joist rot. Joist ends in damp walls, voids with blocked air bricks, leaking pipes and high outside ground levels keep timber wet enough for fungi to grow. Replacing timber without fixing the damp usually means the rot returns.
Do I need building control for floor joist repairs?
Usually not for like-for-like repairs to a few joists, but replacing a whole floor structure can be building work. In Scotland that generally needs a building warrant, and in Northern Ireland council building control applies. We deal with building control where the work needs it.