Gwynedd · Wales
Roof structure repairs in Gwynedd
If you live in Gwynedd and are looking at roof structure repairs, the first question is why the wall moved. 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.
Guide price from£275per rafter inc VAT

- Area
- Gwynedd
- Pricing region
- Wales
- Ground
- Mostly firmer ground
- Towns listed
- 6
Is Gwynedd prone to ground movement?
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.
Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Across Gwynedd, most homes are slate and stone terraces, chapels and cottages, Victorian seaside houses and post-war estates.
Roof structure repairs prices in Gwynedd
Prices in Gwynedd are worked out on Wales 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.
| Item | Guide price | Per |
|---|---|---|
| Repairing or doubling a rafter | £275 – £550 | per rafter |
| Purlin and strut strengthening | £1,100 – £2,750 | per roof |
| Tying in roof spread (straps and ties)est. | £735 – £2,300 | per roof |
How we usually approach roof structure repairs
Repairing or doubling rafters
Cracked, sagging or rotten rafters are strengthened by fixing a new timber alongside, often called doubling, and rotten rafter feet are cut back and spliced. The work is usually done from inside the loft with the tiles left in place, unless the covering is coming off anyway.
Best for: Individual rafters that have cracked, sagged or rotted at the feet
Wall plate replacement
Rotten or crushed wall plates are replaced in short lengths while the rafters above are propped, and bedded on the wall in mortar. The plate is then strapped down to the masonry. It is often combined with rafter foot splices along the same run.
Best for: Rot along the eaves where rafters bear on the wall
Tying in roof spread
New ties, collars or steel straps connect opposite rafters, or fix the rafter feet and wall plate firmly to the ceiling joists, so the outward thrust is resisted. Leaning wall heads are strapped back to the roof, and a badly spread roof may need partly rebuilding first.
Best for: Walls pushed out at eaves level by spreading rafters
What happens during roof structure repairs, step by step?
Send photos
Photograph the roof from across the street, both slopes if you can, and the loft timbers with a torch. Include the eaves and any cracks just below them. From these we can usually tell sag from spread and whether an engineer is needed.
Loft and outside survey
On site we check rafter sizes and spacing, purlins, struts, ties and wall plates, look for rot and past alterations, and measure any lean at the wall head. The covering is noted too, because its weight affects the repair.
Written quote
You receive a no-obligation written quote listing each timber repair, any ties or straps, propping, scaffolding and making good. Once the repair is specified, the figure becomes a fixed price in writing.
What to look for before calling about roof structure repairs
- Struts, collars or ties cut out or missing in the loft
- Horizontal cracks in the wall just below the eaves or ceiling line
- Daylight through the tiles, or timber that is damp, stained or crumbling
- Top of an outside wall leaning out at eaves level
Do you need approval for roof structure repairs in Wales?
In Wales, the Welsh version of the Building Regulations applies. Underpinning and other work that alters or strengthens the structure needs building control approval and inspection; like-for-like repairs often do not. The Party Wall etc. Act 1996 applies to work on party walls and excavation close to a neighbour’s foundations.
Roof structure repairs near you in Gwynedd
Questions about roof structure repairs in Gwynedd
Does the ground around Bangor cause cracking?
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. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Only an investigation on site can say why a particular building has moved.
How much will roof structure repairs cost in Gwynedd?
On Wales rates, roof structure repairs starts from about £275 per rafter, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
Can heavy concrete tiles damage a roof?
Yes, if the frame was designed for lighter slate or tiles and was not strengthened. The extra weight makes rafters and purlins sag and can bring on roof spread. Before re-roofing in a heavier material, have the structure checked and notify building control.
Can the roof be strengthened without removing the tiles?
In most cases, yes. Doubling rafters, adding struts and fitting ties can all be done from inside the loft with the coverings in place. Tiles usually only come off where timber near the eaves is badly decayed, or the roof is being re-covered anyway.
Do roof structure repairs need building control?
Usually yes, where the structure is strengthened or altered, or the covering becomes significantly heavier. In England and Wales that falls under Part A, in Scotland it generally needs a building warrant, and in Northern Ireland council building control approves it. We deal with building control where the work needs it.