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Ask every builder to price the same drawings, structural assumptions, and provisional sums.
£500–£3,000 for small structural work, £15,000–£80,000+ for extensions and conversions
Pricing varies by property type, service requirements, and location. Always compare at least 3 like-for-like quotes before appointing.
Typical timeline: 2–4 weeks for small projects, 3–6 months for extensions and conversions
Check for a proven track record with similar-scale projects in your area
Ask for references and visit completed projects where possible
Confirm they carry public liability insurance (minimum £2 million)
Verify they understand local building regulations and planning requirements
Get a detailed written quotation with a fixed timeline and payment schedule
Emergency callouts, evening/weekend visits, and urgent parts sourcing usually increase rates. If your job is non-urgent, planning ahead and combining smaller tasks into one visit often reduces total spend.
Keep every quote anchored to the same scope, access, and finish assumptions before you decide which provider is actually cheaper.
Ask every builder to price the same drawings, structural assumptions, and provisional sums.
Confirm whether scaffolding, waste removal, skips, and temporary protection are included or excluded.
Get stage payments tied to visible milestones instead of open-ended weekly billing.
Make sure building control, structural engineer sign-off, and making-good items are priced explicitly.
Cheap headline pricing is only useful when the exclusions, paperwork, and finish standard stay explicit. Push these risks into writing before you shortlist anyone.
Large cash deposits before materials, drawings, or programme details are agreed.
Quotes that ignore structural unknowns but still promise a fixed total and start date.
Refusal to discuss insurance, references, or who is responsible for building control coordination.
Pressure to skip written scope, staged payments, or neighbour access planning.
Explore local cost context before requesting quotes.
Many single-storey rear extensions fall under permitted development rights. However, if your property is in a conservation area, is listed, or the extension exceeds size limits, you will need planning permission. Always check with your local planning authority before starting work.
Look for verified customer reviews, proof of public liability insurance, membership of trade bodies like the FMB or NHBC, and ask to see examples of completed projects. A reliable builder will provide a detailed written quotation and a realistic timeline.
Builders handle the above-ground structure — walls, roofs, and finishes. Groundworkers prepare the site, dig foundations, install drainage, and lay services. Many extension or new build projects require both.
A typical loft conversion takes 6–10 weeks depending on the type (Velux, dormer, or mansard). The structural work takes 2–3 weeks, followed by plastering, electrics, plumbing, and finishing.
Compare nearby categories before choosing your final quote shortlist.