Floor joist repairs in Belfast

Postcodes: BT1, BT2, BT7
Population: about 350,000
Area: County Antrim
Pricing region: Northern Ireland

Is County Antrim prone to ground movement?

Belfast (BT1, BT2, BT7) has around 350,000 residents and sits in County Antrim. Nearby, we also cover Newtownabbey (4 miles), Lisburn (7 miles) and Carrickfergus (10 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. Typical buildings in County Antrim: Red-brick terraces in Belfast, Victorian villas, and post-war and newer estates.

What happens when we carry out floor joist repairs in Belfast?

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.
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.

Signs you may need floor joist repairs

Floor bouncing, or ornaments rattling, when someone walks across
A musty smell, or fungal strands showing between the boards
Soft or spongy boards near outside walls, hearths or the bathroom

How much will floor joist repairs cost in Belfast?

Prices in Belfast are worked out on Northern Ireland 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.

Guide prices inc VAT on Northern Ireland rates. Items marked est. are our estimates.
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

Which repair method suits a home in Belfast?

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

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.

Floor joist repairs in Belfast: questions and answers

How much should I budget for floor joist repairs in Belfast?

Guide prices for floor joist repairs in Belfast 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.

Can you survey a property in Belfast?

Yes. We take enquiries from across Belfast, including BT1, BT2, BT7, and from nearby places such as Newtownabbey and Lisburn. Send photos for a free initial view and we will tell you what happens next.

Why do houses in County Antrim crack?

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.

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.

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.

Related work in Belfast

Floor joist repairs near Belfast

Got a bouncy or sinking floor in Belfast? Send a short video of someone walking across it, and we will tell you what it is likely to need.