Gwent · Wales
Floor joist repairs in Gwent
Floor joist repairs in Gwent starts with the ground. Gwent has a mix of ground, with clay in some places and firmer rock in others, and the buildings here are mostly valley terraces on steep hillsides, so the repair has to suit both.
Guide price from£230per joist inc VAT
- Area
- Gwent
- Pricing region
- Wales
- Ground
- Clay in parts
- Towns listed
- 11
What should you know about the ground under Gwent?
The valleys of Blaenau Gwent, Torfaen and Islwyn lie on the South Wales coalfield with extensive historic workings and spoil tips, while Newport and Monmouthshire have Mercia Mudstone, alluvium and Old Red Sandstone.
Historic coal workings are recorded beneath parts of Gwent, and a coal mining search is worth checking where movement is unexplained. Housing stock in Gwent: Valley terraces on steep hillsides, Victorian houses in Newport and Abergavenny, and post-war estates.
Which repair method suits a home in Gwent?
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
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 happens when we carry out floor joist repairs in Gwent?
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.
Signs you may need floor joist repairs
- Floor dipping towards an outside wall or in the middle of the room
- Soft or spongy boards near outside walls, hearths or the bathroom
- Ceiling cracks below that follow the line of the joists
- Floor bouncing, or ornaments rattling, when someone walks across
How much will floor joist repairs cost in Gwent?
The ranges below reflect typical Wales 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 | £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 |
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.
Towns in Gwent we cover for floor joist repairs
Floor joist repairs in Gwent: questions and answers
Is the ground in Gwent prone to subsidence?
The valleys of Blaenau Gwent, Torfaen and Islwyn lie on the South Wales coalfield with extensive historic workings and spoil tips, while Newport and Monmouthshire have Mercia Mudstone, alluvium and Old Red Sandstone. Historic coal workings are recorded beneath parts of Gwent, and a coal mining search is worth checking where movement is unexplained. Only an investigation on site can say why a particular building has moved.
How much will floor joist repairs cost in Gwent?
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.
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.
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.