Cambridgeshire · England
Floor joist repairs in Cambridgeshire
We arrange surveys and price floor joist repairs throughout Cambridgeshire. Much of Cambridgeshire sits on clay that shrinks in dry summers and swells in wet winters, and we take that into account before recommending a method.
Guide price from£260per joist inc VAT
- Area
- Cambridgeshire
- Pricing region
- East of England
- Ground
- Shrinkable clay widespread
- Towns listed
- 8
What should you know about the ground under Cambridgeshire?
Gault Clay underlies much of the Cambridge area and Oxford Clay the west of the county around Peterborough and Huntingdon, while the northern fens are peat and silt that can shrink as they dry. Both clay and peat ground can move with the seasons.
Ground movement here is more often linked to soils, drains and trees than to mining. Across Cambridgeshire, most homes are Victorian terraces in Cambridge and Peterborough, fen-edge cottages, and extensive post-war and new-build estates.
Guide prices for floor joist repairs in Cambridgeshire
These are guide prices for Cambridgeshire, using East of England rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| Item | Guide price | Per |
|---|---|---|
| Splicing or sistering a damaged joist | £260 – £420 | per joist |
| Whole room of joists and boards | £2,100 – £6,300 | per room |
| Sleeper wall rebuild and ventilationest. | £420 – £1,600 | per room |
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
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
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.
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.
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
- Soft or spongy boards near outside walls, hearths or the bathroom
- Floor dipping towards an outside wall or in the middle of the room
- Floor bouncing, or ornaments rattling, when someone walks across
- A musty smell, or fungal strands showing between the boards
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 Cambridgeshire we cover for floor joist repairs
Frequently asked questions
Is the ground in Cambridgeshire prone to subsidence?
Gault Clay underlies much of the Cambridge area and Oxford Clay the west of the county around Peterborough and Huntingdon, while the northern fens are peat and silt that can shrink as they dry. Both clay and peat ground can move with the seasons. 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 Cambridgeshire?
On East of England 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.
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.
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.
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.