Cardiff · South Glamorgan
Floor joist repairs in Cardiff
If a plumber or electrician has recently had the boards up at your Cardiff 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£230per joist inc VAT
- Postcodes
- CF10, CF11, CF24
- Population
- about 370,000
- Area
- South Glamorgan
- Pricing region
- Wales
What should you know about the ground under Cardiff?
Cardiff, South Glamorgan: about 370,000 residents across postcode districts CF10, CF11, CF24. Nearby, we also cover Penarth (3 miles), Caerphilly (7 miles) and Barry (7 miles).
Parts of South Glamorgan 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. What you mostly find across South Glamorgan: Victorian terraces in Cardiff and Penarth, inter-war semis and post-war estates.
Repair options we may recommend
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
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
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
- Floor dipping towards an outside wall or in the middle of the room
- A musty smell, or fungal strands showing between the boards
- Soft or spongy boards near outside walls, hearths or the bathroom
What should you budget for floor joist repairs in Cardiff?
Prices in Cardiff are worked out on Wales rates. They include VAT and are a starting point: access, the extent of the damage and whether an engineer or building control is involved all move the figure.
| Item | Guide price | Per |
|---|---|---|
| Splicing or sistering a damaged joist | £230 – £370 | per joist |
| Whole room of joists and boards | £1,850 – £5,500 | per room |
| Sleeper wall rebuild and ventilationest. | £370 – £1,400 | per room |
Rules for floor joist repairs in Wales
In Wales, small like-for-like repairs do not usually need approval, but work that alters or strengthens the structure needs building control under the Welsh Building Regulations, and the Party Wall etc. Act 1996 can apply to shared walls.
Your floor joist repairs questions
What is the price of floor joist repairs in Cardiff?
Guide prices for floor joist repairs in Cardiff start from about £230 per joist, including VAT, on Wales 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 Cardiff?
Yes. We take enquiries from across Cardiff, including CF10, CF11, CF24, and from nearby places such as Penarth and Caerphilly. Send photos for a free initial view and we will tell you what happens next.
Does the ground around Cardiff cause cracking?
Cardiff is built on Mercia Mudstone, river gravels and alluvium, and the Vale of Glamorgan on Lias limestone and clay. Soft alluvium near the rivers and docks can settle. Only an investigation can say why a particular building has moved.
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.
More repairs we carry out in Cardiff
- Structural surveys and crack monitoring
- Extension pulling away repairs
- Lintel replacement
- Subsidence insurance claim repairs
- Retaining wall repairs
Floor joist repairs near Cardiff
If a floor in Cardiff has dropped after plumbing or heating work, send photos of any lifted boards and notches, and we will price the strengthening.