Falmouth · Cornwall
Floor joist repairs in Falmouth
Houses in Falmouth and across Cornwall with suspended timber ground floors rely on dry walls and a ventilated void to stay sound. When either fails, rot usually starts at the edges of the room long before anything shows in the middle.
Guide price from£260per joist inc VAT

- Postcodes
- TR11
- Population
- about 32,000
- Area
- Cornwall
- Pricing region
- South West
What should you know about the ground under Falmouth?
Postcode districts TR11 cover Falmouth, a Cornwall town of about 32,000 people. Nearby places we cover include Truro (8 miles), Redruth (9 miles) and Camborne (11 miles).
Clay shrinkage is less of a concern in Cornwall, so other causes such as drains, poor footings or older walls are checked first. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Typical buildings in Cornwall: Granite and slate-stone cottages, cob buildings, Victorian terraces and post-war estates.
Symptoms that point to floor joist repairs
- Soft or spongy boards near outside walls, hearths or the bathroom
- A gap opening up between the skirting board and the floor
- Floor dipping towards an outside wall or in the middle of the room
Guide prices for floor joist repairs in Falmouth
For Falmouth we use South West rates. Treat the table as a budget guide, inc VAT; the price you pay is the one on your written quote.
| 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 |
Methods for floor joist repairs
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
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
From first photo to finished repair
Lift boards and inspect
On site we lift a few boards where the floor is worst and check the joist ends, sleeper walls and void with a moisture meter. Outside, we look for high ground, blocked vents and leaks keeping the timber wet.
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.
Relay and ventilate
Boards are relaid or replaced, skirting refitted and air bricks cleared or added outside. We point out anything that would let damp back in, such as soil heaped against the wall, so the repair lasts.
Rules 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.
Frequently asked questions
How much will floor joist repairs cost in Falmouth?
Guide prices for floor joist repairs in Falmouth start from about £260 per joist, including VAT, on South West rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Falmouth?
Yes. We take enquiries from across Falmouth, including TR11, and from nearby places such as Truro and Redruth. Send photos for a free initial view and we will tell you what happens next.
Is the ground in Cornwall prone to subsidence?
Cornwall is mostly granite and slate with little shrinkable clay, so clay subsidence is less common than in the south-east. Historic tin and copper mining has left shafts and workings in places such as Camborne and Redruth, and mining searches are routine there. Only an investigation can say why a particular building has moved.
Is a sagging floor dangerous?
A gentle, long-standing sag is usually not dangerous, and many older floors have moved slightly over a century. A sag that is getting worse, soft boards or a floor dropping near a wall needs checking soon, because rotten joist ends can lose their bearing.
Why is my floor bouncy?
A bouncy floor usually means the joists are deflecting too much, often because they span too far, have lost their strutting or have been weakened by notches. It rarely means imminent failure, but it is worth checking, especially if the bounce appeared after work in the room.
Other structural repairs in Falmouth
- Retaining wall repairs
- Structural crack repairs
- Boundary and garden wall repairs
- Bowing wall repairs
- Subsidence repairs
Floor joist repairs near Falmouth
Each joist, sleeper wall and air brick at your Falmouth property is itemised in the written quote, then fixed in price once the repair is specified.