Isle of Wight · England
Floor joist repairs in Isle of Wight
Across Isle of Wight, requests for floor joist repairs usually begin with a crack someone has noticed getting wider. Shrinkable clay is widespread in Isle of Wight. A repair only lasts if the reason for the movement has stopped.
Guide price from£280per joist inc VAT

- Area
- Isle of Wight
- Pricing region
- South East
- Ground
- Shrinkable clay widespread
- Towns listed
- 4
Why does the ground in Isle of Wight matter for floor joist repairs?
The island has clays, sands and chalk, and the south coast around Ventnor sits on one of the largest urban landslide complexes in Europe. Ground movement there is a landslip question as much as a clay one.
Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Isle of Wight: Victorian seaside villas, terraces in Ryde and Newport, and post-war bungalows.
Repair options we may recommend
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
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
What to expect when we carry out floor joist repairs
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.
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.
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.
Is it time for floor joist repairs? Common signs
- A musty smell, or fungal strands showing between the boards
- Floor dipping towards an outside wall or in the middle of the room
- Floor bouncing, or ornaments rattling, when someone walks across
- Soft or spongy boards near outside walls, hearths or the bathroom
What should you budget for floor joist repairs in Isle of Wight?
The ranges below reflect typical South East 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 | £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.
Survey visits in parts of Isle of Wight are by arrangement because of travel and access. We can still give a free initial view from photos, and we tell you any travel cost before a visit is booked.
Towns in Isle of Wight we cover for floor joist repairs
Your floor joist repairs questions
Is the ground in Isle of Wight prone to subsidence?
The island has clays, sands and chalk, and the south coast around Ventnor sits on one of the largest urban landslide complexes in Europe. Ground movement there is a landslip question as much as a clay one. 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 Isle of Wight?
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.
What is sistering a floor joist?
Sistering is fixing a new length of timber alongside an existing joist so the two share the load. It strengthens a notched, cracked or sagging joist without removing it, so it is quicker and less disruptive than replacement.
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.
Can floor joists be repaired without taking up the whole floor?
Yes, in most cases only the boards over the affected joists need lifting, and three or four boards are often enough to sister a joist or splice a rotten end. Widespread rot is the exception, because the whole floor must come up to remove the decay.