County Londonderry · Northern Ireland
Floor joist repairs in County Londonderry
We carry out floor joist repairs across County Londonderry, from the larger towns to smaller places nearby. Clay shrinkage is less of a concern in County Londonderry, so other causes such as drains, poor footings or older walls are checked first. Every job starts with the cause, then the repair is specified to match it.
Guide price from£220per joist inc VAT
- Area
- County Londonderry
- Pricing region
- Northern Ireland
- Ground
- Mostly firmer ground
- Towns listed
- 4
What is the ground like in County Londonderry?
County Londonderry has basalt, older hard rock and glacial deposits, with soft river ground along the Foyle and Bann.
Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in County Londonderry: Georgian and Victorian houses in Derry, brick terraces and post-war estates.
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.
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
- Soft or spongy boards near outside walls, hearths or the bathroom
- A musty smell, or fungal strands showing between the boards
- Floor dipping towards an outside wall or in the middle of the room
- Ceiling cracks below that follow the line of the joists
What should you budget for floor joist repairs in County Londonderry?
These are guide prices for County Londonderry, using Northern Ireland 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 | £220 – £350 | per joist |
| Whole room of joists and boards | £1,750 – £5,300 | per room |
| Sleeper wall rebuild and ventilationest. | £350 – £1,300 | per room |
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
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
Do you need approval for floor joist repairs in Northern Ireland?
In Northern Ireland, minor repairs usually need no approval, but structural work comes under the Building Regulations (Northern Ireland) 2012 and council building control. There is no Party Wall Act in Northern Ireland.
Floor joist repairs near you in County Londonderry
Your floor joist repairs questions
Does the ground around Derry cause cracking?
County Londonderry has basalt, older hard rock and glacial deposits, with soft river ground along the Foyle and Bann. 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 County Londonderry?
On Northern Ireland rates, floor joist repairs starts from about £220 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.
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.