Sunbury-on-Thames · Surrey
Floor joist repairs in Sunbury-on-Thames
Houses in Sunbury-on-Thames and across Surrey 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£280per joist inc VAT

- Postcodes
- KT12, TW16, TW17
- Population
- about 28,000
- Area
- Surrey
- Pricing region
- South East
Why does the ground in Surrey matter for floor joist repairs?
Sunbury-on-Thames is in Surrey and takes in postcode districts KT12, TW16, TW17. About 28,000 people live there. Nearby, we also cover Ashford (3 miles), Weybridge (3 miles) and East Molesey (3 miles).
Surrey is one of the parts of the UK where clay soils are most likely to move with the seasons. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Surrey: Victorian and Edwardian villas, 1930s semis and detached houses in the commuter towns, and post-war estates.
Methods for floor joist repairs
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
Splicing ends and fitting hangers
Where only the end has rotted, it is cut back to sound timber and a new piece is fixed alongside, bearing on the wall or on a new joist hanger. Missing or under-nailed hangers elsewhere are replaced at the same time. The damp in the wall must be fixed too.
Best for: Rotten joist ends in damp solid walls
From first photo to finished repair
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.
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.
Symptoms that point to floor joist repairs
- A gap opening up between the skirting board and the floor
- Soft or spongy boards near outside walls, hearths or the bathroom
- Floor bouncing, or ornaments rattling, when someone walks across
Guide prices for floor joist repairs in Sunbury-on-Thames
Guide prices below are for homes in Sunbury-on-Thames, on South East rates and including VAT. A survey or good photos let us turn them into a fixed written price.
| Item | Guide price | Per |
|---|---|---|
| Splicing or sistering a damaged joist | £280 – £450 | per joist |
| Whole room of joists and boards | £2,250 – £6,700 | per room |
| Sleeper wall rebuild and ventilationest. | £450 – £1,700 | per room |
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 Sunbury-on-Thames?
Guide prices for floor joist repairs in Sunbury-on-Thames start from about £280 per joist, including VAT, on South East rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Sunbury-on-Thames?
Yes, Sunbury-on-Thames is covered, along with postcode districts KT12, TW16, TW17. We also cover nearby Ashford and Weybridge.
Is the ground in Surrey prone to subsidence?
North Surrey sits on London Clay, the south on Weald Clay, with chalk along the North Downs and sands in the west. Large gardens with mature trees on clay make seasonal subsidence a familiar problem. Only an investigation can say why a particular building has moved.
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.
Other structural repairs in Sunbury-on-Thames
- Resin injection ground stabilisation
- Crack stitching
- Chimney stack repairs
- Wall tie replacement
- Boundary and garden wall repairs
Floor joist repairs near Sunbury-on-Thames
Get a free initial assessment of a sagging floor in Sunbury-on-Thames from your photos or a call, before you commit to anything.