Dorchester · Dorset
Floor joist repairs in Dorchester
If a plumber or electrician has recently had the boards up at your Dorchester home, the joists they worked around are worth a look. Deep notches and holes in the wrong place weaken joists quickly, and sistering them is usually a short, tidy job.
Guide price from£260per joist inc VAT

- Postcodes
- DT1
- Population
- about 17,000
- Area
- Dorset
- Pricing region
- South West
Is Dorset prone to ground movement?
Dorchester (DT1) has around 17,000 residents and sits in Dorset. Nearby places we cover include Weymouth (7 miles), Yeovil (18 miles) and Poole (20 miles).
Parts of Dorset have clay that can shrink near trees in dry spells. Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in Dorset: Stone and brick villages, Victorian villas in Bournemouth, and inter-war and post-war semis.
Repair options we may recommend
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 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.
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.
Is it time for floor joist repairs? Common signs
- A musty smell, or fungal strands showing between the boards
- A gap opening up between the skirting board and the floor
- Floor bouncing, or ornaments rattling, when someone walks across
What should you budget for floor joist repairs in Dorchester?
The ranges below reflect typical South West 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 | £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 |
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.
Your floor joist repairs questions
What is the price of floor joist repairs in Dorchester?
Guide prices for floor joist repairs in Dorchester 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 carry out floor joist repairs in Dorchester?
Yes. We take enquiries from across Dorchester, including DT1, and from nearby places such as Weymouth and Yeovil. Send photos for a free initial view and we will tell you what happens next.
Does the ground around Dorchester cause cracking?
Dorset mixes chalk downs, Oxford and Kimmeridge Clays in the vales, and the sands and gravels of the Poole basin. Clay vales can shrink and swell, and parts of the coast are known for landslip. Only an investigation can say why a particular building has moved.
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.
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.
More repairs we carry out in Dorchester
- Wall tie replacement
- Retaining wall repairs
- Structural surveys and crack monitoring
- Bowing wall repairs
- Roof structure repairs
Floor joist repairs near Dorchester
Got a bouncy or sinking floor in Dorchester? Send a short video of someone walking across it, and we will tell you what it is likely to need.