South Glamorgan · Wales
Floor joist repairs in South Glamorgan
We carry out floor joist repairs across South Glamorgan, from the larger towns to smaller places nearby. South Glamorgan has a mix of ground, with clay in some places and firmer rock in others. Every job starts with the cause, then the repair is specified to match it.
Guide price from£230per joist inc VAT
- Area
- South Glamorgan
- Pricing region
- Wales
- Ground
- Clay in parts
- Towns listed
- 4
What should you know about the ground under South Glamorgan?
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.
Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in South Glamorgan: Victorian terraces in Cardiff and Penarth, inter-war semis and post-war estates.
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 dipping towards an outside wall or in the middle of the room
- Soft or spongy boards near outside walls, hearths or the bathroom
What should you budget for floor joist repairs in South Glamorgan?
Guide prices below are for homes in South Glamorgan, on Wales 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 | £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 |
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
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
What to expect when we carry out floor joist repairs
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.
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.
Do you need approval 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.
Find floor joist repairs in your South Glamorgan town
Your floor joist repairs questions
Why do houses in South Glamorgan crack?
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. 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 South Glamorgan?
On Wales rates, floor joist repairs starts from about £230 per joist, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
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.
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.
Do I need building control for floor joist repairs?
Usually not for like-for-like repairs to a few joists, but replacing a whole floor structure can be building work. In Scotland that generally needs a building warrant, and in Northern Ireland council building control applies. We deal with building control where the work needs it.