Llandudno · Gwynedd
Floor joist repairs in Llandudno
Whether it is one soft patch by the bathroom or a whole room dropping towards the wall, floor joist repairs in Llandudno are priced only after the timber has been seen. Rot, notches and failed supports each need a different fix, and the quote says which.
Guide price from£230per joist inc VAT

- Postcodes
- LL30
- Population
- about 15,000
- Area
- Gwynedd
- Pricing region
- Wales
Is Gwynedd prone to ground movement?
Llandudno, Gwynedd: about 15,000 residents across postcode districts LL30. Neighbouring towns we cover: Colwyn Bay (5 miles), Abergele (11 miles) and Rhyl (14 miles).
Most of Gwynedd is on firmer ground than the clay belts of the south-east. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Housing stock in Gwynedd: Slate and stone terraces, chapels and cottages, Victorian seaside houses and post-war 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.
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.
What to look for before calling about floor joist repairs
- Soft or spongy boards near outside walls, hearths or the bathroom
- Floor bouncing, or ornaments rattling, when someone walks across
- A musty smell, or fungal strands showing between the boards
Floor joist repairs prices in Llandudno
The ranges below reflect typical Wales 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 | £230 – £370 | per joist |
| Whole room of joists and boards | £1,850 – £5,500 | per room |
| Sleeper wall rebuild and ventilationest. | £370 – £1,400 | 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
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
Rules 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.
Questions about floor joist repairs in Llandudno
How much should I budget for floor joist repairs in Llandudno?
Guide prices for floor joist repairs in Llandudno start from about £230 per joist, including VAT, on Wales 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 Llandudno?
Yes, Llandudno is covered, along with postcode districts LL30. We also cover nearby Colwyn Bay and Abergele.
Why do houses in Gwynedd crack?
Gwynedd and Anglesey are mostly hard rock with glacial deposits, so clay shrinkage is uncommon. Historic slate quarrying and metal mining have left tips and workings in places. Only an investigation can say why a particular building has moved.
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.
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.
Related work in Llandudno
- Concrete repairs
- Lintel replacement
- Underpinning
- Wall tie replacement
- Resin injection ground stabilisation
Floor joist repairs near Llandudno
Get a free initial assessment of a sagging floor in Llandudno from your photos or a call, before you commit to anything.