Ballymoney · County Antrim
Floor joist repairs in Ballymoney
Houses in Ballymoney and across County Antrim with suspended timber ground floors rely on dry walls and a ventilated void to stay sound. When either fails, rot usually starts at the edges of the room long before anything shows in the middle.
Guide price from£220per joist inc VAT
- Postcodes
- BT53
- Population
- about 10,000
- Area
- County Antrim
- Pricing region
- Northern Ireland
Is County Antrim prone to ground movement?
We cover Ballymoney and its postcode districts BT53, part of County Antrim, with a population of roughly 10,000. Nearby, we also cover Coleraine (7 miles), Ballymena (17 miles) and Limavady (17 miles).
Clay shrinkage is less of a concern in County Antrim, so other causes such as drains, poor footings or older walls are checked first. Historic brine and salt working has caused ground movement in parts of County Antrim in the past. What you mostly find across County Antrim: red-brick terraces in Belfast, Victorian villas, and post-war and newer estates.
Methods for floor joist repairs
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
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
From first photo to finished repair
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.
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.
Symptoms that point to floor joist repairs
- Floor bouncing, or ornaments rattling, when someone walks across
- Ceiling cracks below that follow the line of the joists
- Floor dipping towards an outside wall or in the middle of the room
Guide prices for floor joist repairs in Ballymoney
The ranges below reflect typical Northern Ireland 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 | £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 |
Rules 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.
Frequently asked questions
How much will floor joist repairs cost in Ballymoney?
Guide prices for floor joist repairs in Ballymoney start from about £220 per joist, including VAT, on Northern Ireland rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Ballymoney?
Yes. We take enquiries from across Ballymoney, including BT53, and from nearby places such as Coleraine and Ballymena. Send photos for a free initial view and we will tell you what happens next.
Is the ground in County Antrim prone to subsidence?
County Antrim is largely basalt over chalk, with soft estuarine 'sleech' along Belfast Lough that is notorious for settlement. Historic salt mining is recorded near Carrickfergus. Only an investigation can say why a particular building has moved.
What causes rot in floor joists?
Damp causes almost all joist rot. Joist ends in damp walls, voids with blocked air bricks, leaking pipes and high outside ground levels keep timber wet enough for fungi to grow. Replacing timber without fixing the damp usually means the rot returns.
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.
Other structural repairs in Ballymoney
- Chimney stack repairs
- Structural surveys and crack monitoring
- Brick arch repairs
- Resin injection ground stabilisation
- Retaining wall repairs
Floor joist repairs near Ballymoney
Send photos of the floor and the outside wall at your Ballymoney property for a free initial assessment and a no-obligation written quote.