Roof structure repairs in Hertfordshire

Area: Hertfordshire
Pricing region: East of England
Ground: Shrinkable clay widespread
Towns listed: 19

What is the ground like in Hertfordshire?

Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in Hertfordshire: Garden-city houses in Letchworth and Welwyn, 1930s semis, Victorian terraces and post-war new-town estates.

How we usually approach roof structure repairs

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

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

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.
Engineer’s design where needed
Where purlins, struts or ties must be redesigned, or the roof carries a heavier covering, an independent chartered structural engineer is appointed to specify the work. We can arrange this, and their design sets the sizes and fixings.

What to look for before calling about roof structure repairs

Daylight through the tiles, or timber that is damp, stained or crumbling
Top of an outside wall leaning out at eaves level
Ridge line dipping in the middle when seen from the street
Horizontal cracks in the wall just below the eaves or ceiling line

Roof structure repairs prices in Hertfordshire

For Hertfordshire we use East of England 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 East of England rates. Items marked est. are our estimates.
Item	Guide price	Per
Repairing or doubling a rafter	£315 – £630	per rafter
Purlin and strut strengthening	£1,250 – £3,150	per roof
Tying in roof spread (straps and ties)est.	£840 – £2,600	per roof

Roof structure repairs: purlin and struts added, roof spread tied in. Indicative drawing, not to scale.

Do you need approval for roof structure repairs in England?

In England, underpinning and other work that alters or strengthens a wall or foundation is building work under the Building Regulations (Part A, structure), so building control approves and inspects it. Like-for-like repairs often are not, and we tell you which applies before a price is agreed. Work to a party wall, or excavation close to a neighbour’s foundations, can also need a notice under the Party Wall etc. Act 1996.

Find roof structure repairs in your Hertfordshire town

Questions about roof structure repairs in Hertfordshire

Why do houses in Hertfordshire crack?

South Hertfordshire around Watford, Borehamwood and Potters Bar is London Clay, while the north and west are chalk with clay-with-flints and the east has boulder clay. The clay areas are prone to seasonal subsidence near trees. 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 Hertfordshire?

On East of England rates, roof structure repairs starts from about £315 per rafter, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.

What is roof spread?

Roof spread is when the feet of the rafters move outward because nothing is tying them together firmly enough. As they spread, the ridge drops and the tops of the walls are pushed out, often with a horizontal crack below the eaves. It is fixed by adding ties, collars or straps, sometimes with rebuilding.

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.

Why are there cracks just below the eaves?

A horizontal crack just below the eaves, along the front or back wall, is a common sign of roof spread. The rafters push the top of the wall outward and the masonry cracks where it hinges. Corroded wall ties can cause similar cracks, so the cause needs checking.