South Glamorgan · Wales
Roof structure repairs in South Glamorgan
South Glamorgan has its own mix of ground and building types, and that shapes how roof structure repairs is done here. South Glamorgan has a mix of ground, with clay in some places and firmer rock in others.
Guide price from£275per rafter inc VAT
- Area
- South Glamorgan
- Pricing region
- Wales
- Ground
- Clay in parts
- Towns listed
- 4
What should you know about the ground under South Glamorgan?
Cardiff is built on Mercia Mudstone, river gravels and alluvium, and the Vale of Glamorgan on Lias limestone and clay. Soft alluvium near the rivers and docks can settle.
Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across South Glamorgan: Victorian terraces in Cardiff and Penarth, inter-war semis and post-war estates.
Symptoms that point to roof structure repairs
- Horizontal cracks in the wall just below the eaves or ceiling line
- Daylight through the tiles, or timber that is damp, stained or crumbling
- Ridge line dipping in the middle when seen from the street
- Top of an outside wall leaning out at eaves level
Guide prices for roof structure repairs in South Glamorgan
The ranges below reflect typical Wales costs for roof structure repairs, including VAT. Scaffold, access and making good can push a job to the top of the range.
| 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 |
Methods for roof structure repairs
Purlin and strut strengthening
Undersized purlins are strengthened with extra timber or replaced, and new struts are taken down to a load-bearing wall. Where there is no suitable wall, an engineer designs the load path. Temporary props hold the roof while members are changed.
Best for: Sagging slopes, slim purlins and struts removed from the loft
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
From first photo to finished repair
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.
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.
Find roof structure repairs in your South Glamorgan town
Frequently asked questions
Why do houses in South Glamorgan crack?
Cardiff is built on Mercia Mudstone, river gravels and alluvium, and the Vale of Glamorgan on Lias limestone and clay. Soft alluvium near the rivers and docks can settle. Ground movement here is more often linked to soils, drains and trees than to mining. Only an investigation on site can say why a particular building has moved.
How much will roof structure repairs cost in South Glamorgan?
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.
Do I need a structural engineer for roof repairs?
For like-for-like repairs to a few rafters, often not. Where purlins, struts or ties are being redesigned, the covering is getting heavier or the walls are being pushed out, you usually do. Where the repair needs an engineer’s design or sign-off, an independent chartered structural engineer is appointed, and we can arrange this.
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.
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.