Floor joist repairs in Lisburn

Postcodes: BT17, BT27, BT28
Population: about 78,000
Area: County Antrim
Pricing region: Northern Ireland

Why does the ground in County Antrim matter for floor joist repairs?

Lisburn is in County Antrim and takes in postcode districts BT17, BT27, BT28. About 78,000 people live there. Nearby, we also cover Belfast (7 miles), Newtownabbey (11 miles) and Craigavon (15 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. Across County Antrim, most homes are red-brick terraces in Belfast, Victorian villas, and post-war and newer estates.

What happens during floor joist repairs, step by step?

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.

What to look for before calling about floor joist repairs

A gap opening up between the skirting board and the floor
Soft or spongy boards near outside walls, hearths or the bathroom
Ceiling cracks below that follow the line of the joists

Floor joist repairs prices in Lisburn

These are guide prices for Lisburn, using Northern Ireland rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.

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

How we usually approach floor joist repairs

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

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.

Questions about floor joist repairs in Lisburn

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

Guide prices for floor joist repairs in Lisburn 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 Lisburn?

We do. Lisburn and the surrounding area are covered, including nearby Belfast and Newtownabbey. A free initial assessment from your photos is the first step.

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.

What is sistering a floor joist?

Sistering is fixing a new length of timber alongside an existing joist so the two share the load. It strengthens a notched, cracked or sagging joist without removing it, so it is quicker and less disruptive than replacement.

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.

Related work in Lisburn

Floor joist repairs near Lisburn

For a guide price on floor joist repairs in Lisburn, use the quote tool or send photos of the dip, any soft boards and the air bricks.