Question answered
Roofer or builder: who should do the job?
The short answer
Use a roofer when the work is on the roof covering and the details that keep water out: tiles, slates, flat roofing, lead flashings, ridges, verges and gutters. Use a builder, often with an engineer or designer, when the job changes the structure: moving rafters, forming an opening, removing a chimney breast or building an extension. Large projects need a builder and a roofer working to one plan.
The right trade depends on whether the job is about the weatherproof skin of the roof or the structure underneath it. Many projects need both, in the right order.
Jobs that belong with a roofer
A roofer's craft is stopping weather getting into the top of a building. That covers re-covering a pitched roof in tiles or slate, repairing slipped or cracked units, re-bedding or replacing ridge and hip tiles, and renewing a flat roof membrane. It also covers the junctions where leaks usually begin: the flashing, which is the lead strip sealing roof to wall or chimney; the valley, the gutter-like channel at the meeting of two roof slopes; and the verge, where the covering finishes along a gable wall.
Gutters, fascias and soffits belong in this group. Together they make up the roofline, the visible edge where roof meets wall, and they depend on the covering above them. A roofer can also trace why a ceiling is stained, because the fault so often starts a long way from the mark.
If your question is why water is getting in, or whether a covering is simply worn out, start with a roofer. Our guide on roof coverings on the Sussex coast shows what suits an exposed house, and you can see how we work from the Watertight Worthing Roofing home page.
Jobs that start with a builder
Work that changes how the roof carries its load is structural. Cutting into rafters, forming a new opening, replacing a purlin, building a dormer or converting a loft all sit with a builder, usually with a structural engineer or architectural designer behind the drawings. The Planning Portal lists structural alterations among the things that bring a building control application.
An extension follows the same logic. Its roof is one part of a wider build in which foundations, walls, floor and roof arrive in sequence, and a builder runs that sequence. The roofer comes in for the covering once the structure is ready, which is why roofers often work as sub-contractors on larger schemes.
Planning also enters the picture. In a conservation area or the National Park, a dormer cannot go ahead as permitted development, so it needs an application. That is a question for the planning team before anyone orders materials, and nothing a roofer on the doorstep should be waving through on your behalf.
Chimney breasts and heavier coverings
Two jobs blur the line between the trades. The first is taking out a chimney breast, the part of the chimney that projects into a room. The Planning Portal states that building regulations approval always applies to that work, because breasts form part of the building's structure, while a stack that stops at the roofline may be treated differently. Removing a breast is a builder's job, often with an engineer. When the chimney stands on a wall shared with next door, the neighbour has to be notified as well; see party wall rules for roof work for how that works.
The second is a change of covering. Swapping light slate for heavier concrete tiles can raise the load on the timbers. Under Approved Document A, extra loading of more than 15% is a significant change, and the Planning Portal puts the trigger at 15 per cent or more. Either way, building control and a structural check come into it.
A roofer can price the new covering, but someone with the right training has to confirm that the existing timbers will carry it, and that confirmation should be on paper before the order goes in. Who to ring is covered in building control in Adur and Worthing.
Getting the two trades to work together
On a mixed project, agree who is responsible for what before anyone starts. The builder usually owns the structure and the programme. The roofer owns the covering, the flashings and the places where the new roof meets an old wall. Water finds the gaps between trades, so ask both firms to say who takes the lead at those junctions.
Ask each firm to quote for its own part in writing, with a total price and a description of what is included. Raise scaffolding early, because it affects the start date as much as the price: if a single scaffold serves both trades, settle who arranges and pays for it, and who is responsible when it has to stay up longer than planned.
Payment follows similar logic, and it is worth settling before the first day on site. A builder may want stage payments, while a roofer on a small job is normally paid once the work is done. Read should you pay a roofer a deposit before you agree terms with either. And if the job is only a covering, one trade is enough; hiring two adds cost without adding anything useful.
Choosing a trade: two more questions
Who should replace a rotten rafter end at the eaves?
It depends on how much timber is involved. Replacing a short length of decayed rafter foot or fascia board while re-covering is often a roofer's task. Anything that alters how the roof carries its load, or involves several rafters, is structural and deserves a builder or engineer's view first.
Do I need a builder to replace a chimney stack above the roof?
Not necessarily. Rebuilding or repointing a stack above the roofline is commonly done by a roofer with bricklaying skill or by a builder. Removing the breast below, inside the house, is different: it needs building regulations approval, and notice to the neighbour where the chimney stands on a shared wall.
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