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Dorset · England

Roof structure repairs in Dorset

Across Dorset, requests for roof structure repairs usually begin with a crack someone has noticed getting wider. Dorset has a mix of ground, with clay in some places and firmer rock in others. A repair only lasts if the reason for the movement has stopped.

Guide price from£310per rafter inc VAT

New timber purlin and struts strengthening the rafters in a loft
Area
Dorset
Pricing region
South West
Ground
Clay in parts
Towns listed
7

What should you know about the ground under Dorset?

Dorset mixes chalk downs, Oxford and Kimmeridge Clays in the vales, and the sands and gravels of the Poole basin. Clay vales can shrink and swell, and parts of the coast are known for landslip.

Ground movement here is more often linked to soils, drains and trees than to mining. Across Dorset, most homes are stone and brick villages, Victorian villas in Bournemouth, and inter-war and post-war semis.

What to expect when we carry out roof structure repairs

  1. 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.

  2. 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.

  3. Prop, strengthen and tie

    The roof is propped where members are being changed, then rafters, purlins, struts and ties are repaired or added as specified. Coverings disturbed by the work are relaid, and building control inspects where the work needs it.

Is it time for roof structure repairs? Common signs

  • Horizontal cracks in the wall just below the eaves or ceiling line
  • Top of an outside wall leaning out at eaves level
  • Ridge line dipping in the middle when seen from the street
  • Struts, collars or ties cut out or missing in the loft

What should you budget for roof structure repairs in Dorset?

For Dorset we use South West 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 South West rates. Items marked est. are our estimates.
ItemGuide pricePer
Repairing or doubling a rafter£310 – £620per rafter
Purlin and strut strengthening£1,250 – £3,100per roof
Tying in roof spread (straps and ties)est.£825 – £2,600per roof

Repair options we may recommend

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

Roof structure repairs: purlin and struts added, roof spread tied inNEW PURLINSTRUTS + CEILING TIESPREADINDICATIVE · NOT TO SCALE
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 Dorset town

Your roof structure repairs questions

Why do houses in Dorset crack?

Dorset mixes chalk downs, Oxford and Kimmeridge Clays in the vales, and the sands and gravels of the Poole basin. Clay vales can shrink and swell, and parts of the coast are known for landslip. 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 Dorset?

On South West rates, roof structure repairs starts from about £310 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 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.

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.

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.

Related work in Dorset

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.

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