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Dyfed · Wales

Floor joist repairs in Dyfed

If you live in Dyfed and are looking at floor joist repairs, the first question is why the wall moved. Most of Dyfed is on firmer ground than the clay belts of the south-east; parts of Dyfed lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause.

Guide price from£230per joist inc VAT

New timber joist bolted alongside a rotten joist under lifted floorboards
Area
Dyfed
Pricing region
Wales
Ground
Mostly firmer ground
Towns listed
6

Why does the ground in Dyfed matter for floor joist repairs?

The western edge of the South Wales coalfield lies beneath Llanelli, Ammanford and parts of Pembrokeshire, while the rest of the area is older hard rock with glacial deposits in the valleys.

Parts of Dyfed lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Typical buildings in Dyfed: Stone cottages, Victorian terraces in Llanelli and Carmarthen, and post-war estates.

What to look for before calling about floor joist repairs

  • Soft or spongy boards near outside walls, hearths or the bathroom
  • Floor dipping towards an outside wall or in the middle of the room
  • Floor bouncing, or ornaments rattling, when someone walks across
  • A musty smell, or fungal strands showing between the boards

Floor joist repairs prices in Dyfed

For Dyfed we use Wales rates. Treat the table as a budget guide, inc VAT; the price you pay is the one on your written quote.

Guide prices inc VAT on Wales rates. Items marked est. are our estimates.
ItemGuide pricePer
Splicing or sistering a damaged joist£230 – £370per joist
Whole room of joists and boards£1,850 – £5,500per room
Sleeper wall rebuild and ventilationest.£370 – £1,400per room

How we usually approach floor joist repairs

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

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

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

What happens during floor joist repairs, step by step?

  1. 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.

  2. 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.

  3. 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.

Floor joist repair: a new joist sistered alongside a decayed one on the sleeper wallFLOORBOARDSNEW SISTER JOISTBOLTED ONSLEEPER WALLROT AT JOIST ENDINDICATIVE · NOT TO SCALE
Floor joist repair: a new joist sistered alongside a decayed one on the sleeper wall. Indicative drawing, not to scale.

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 Dyfed we cover for floor joist repairs

Questions about floor joist repairs in Dyfed

Is the ground in Dyfed prone to subsidence?

The western edge of the South Wales coalfield lies beneath Llanelli, Ammanford and parts of Pembrokeshire, while the rest of the area is older hard rock with glacial deposits in the valleys. Parts of Dyfed lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Only an investigation on site can say why a particular building has moved.

How much will floor joist repairs cost in Dyfed?

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.

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.

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.

Other structural repairs in Dyfed

Next step

Send us photos of the crack or movement

A free initial assessment from your photos, then a no-obligation written quote. If an engineer, drain survey or monitoring is needed first, we say so before you spend anything.

CallGet a quote