West Sussex · England
Floor joist repairs in West Sussex
Looking for floor joist repairs in West Sussex? Send us photos for a free initial view. West Sussex is one of the parts of the UK where clay soils are most likely to move with the seasons, so we look at the ground, drains and nearby trees before recommending anything.
Guide price from£280per joist inc VAT

- Area
- West Sussex
- Pricing region
- South East
- Ground
- Shrinkable clay widespread
- Towns listed
- 11
Why does the ground in West Sussex matter for floor joist repairs?
North West Sussex around Crawley and Horsham sits on Weald Clay, the South Downs are chalk, and the coastal plain has brickearth and gravels. The Weald Clay is prone to shrink-swell movement near trees.
Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across West Sussex: Wealden cottages, 1930s semis and bungalows on the coast, and new-town estates in Crawley.
How we usually approach 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
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
What happens during floor joist repairs, step by step?
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.
What to look for before calling about floor joist repairs
- Ceiling cracks below that follow the line of the joists
- A gap opening up between the skirting board and the floor
- 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 joist repairs prices in West Sussex
Guide prices below are for homes in West Sussex, 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 |
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.
Find floor joist repairs in your West Sussex town
- Crawley
- Worthing
- Bognor Regis
- Littlehampton
- Horsham
- Haywards Heath
- Chichester
- Burgess Hill
- East Grinstead
- Shoreham-by-Sea
- Lancing
Questions about floor joist repairs in West Sussex
Why do houses in West Sussex crack?
North West Sussex around Crawley and Horsham sits on Weald Clay, the South Downs are chalk, and the coastal plain has brickearth and gravels. The Weald Clay is prone to shrink-swell movement near trees. Ground movement here is more often linked to soils, drains and trees than to mining. Only an investigation on site can say why a particular building has moved.
How much will floor joist repairs cost in West Sussex?
On South East rates, floor joist repairs starts from about £280 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.
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.