How to Hire a Contractor in the UK (Especially for an Older House)

Most bad building jobs in Britain are lost at the enquiry stage. The householder rings four numbers off the side of a van, describes the work in one paragraph, then compares three prices that were never for the same job.

That risk multiplies in an older house. Anything built before roughly 1919 tends to have solid brick walls with no cavity, lath and lime plaster, timber sash windows, salt-glazed clay drains and sometimes wiring that predates the 1966 regulations. A competent builder who has spent fifteen years on 1990s estates can damage that fabric simply by following his usual habits. Hiring well means testing for that, not just for price.

These points are not matters of preference, and they change who you are allowed to hire. Planning permission and Building Regulations are separate systems and both can bite; our guide to when you need planning permission and building regs sets out which applies.

• •Gas: any work on an appliance, pipe or flue needs someone Gas Safe registered. Turn the card over — the back lists what they are qualified to touch, and boiler tickets do not cover cookers.
• •Electrics: new circuits, consumer unit swaps and most bathroom work are notifiable under Part P. Use a NICEIC, NAPIT or ELECSA electrician, or notify Building Control yourself and pay £250-£450.
• •Asbestos: assume it is in anything built or refurbished before 2000 — textured coatings, boiler cupboard panels, soffits, floor tiles. A survey is £250-£500.
• •Lead paint: original joinery and sash boxes in pre-1970s houses. Agree the stripping method before anyone brings a sander in.
• •Listed buildings and conservation areas: consent is separate from planning, and unauthorised alteration is a criminal offence.
• •Party Wall etc. Act 1996: two months' notice for work on a shared wall, one month for excavating near a neighbour's foundations.

Your tools and materials for hiring are paperwork. The key document is a written schedule of works: numbered clauses, room by room, saying what is removed, what is installed and to what standard. Three builders pricing the same list give comparable figures; three pricing a conversation do not, which is why comparing contractor estimates is so often a mess.

• •The numbered schedule, plus drawings at 1:50 if anything structural moves.
• •Structural engineer's calculations where a wall or beam is involved: £400-£900 per opening.
• •On a pre-1919 house, an RICS Level 3 survey (£600-£1,500) and, if damp is suspected, an independent damp and timber report — not a free 'survey' from a firm selling injected damp courses.
• •A CCTV drain survey, £100-£250, before anyone prices an extension or a bathroom.
• •What you are supplying yourself, with a prime cost sum against each item so it is priced, not assumed.

Allow six to fourteen weeks from first enquiry to boots on site. Builders worth having are booked three to six months ahead, so anyone free on Monday in April is telling you something. A site visit takes 45-90 minutes and a measured quote another four to ten working days.

In 2026, expect a general builder at £180-£280 per person per day (£250-£400 in London), an electrician at £250-£400, a plumber at £300-£450, a plasterer at £180-£250 and a lime specialist at £250-£350. A main contractor adds 15-25% for overhead and profit — not padding, it buys you one throat to choke. Fees sit on top: architect 8-12% of build cost, party wall surveyor £900-£1,800. Carry 10% contingency on a modern house and 20-25% pre-1919, and read how to budget for a renovation first.

Do not skip step six. A verbal agreement still binds under the Consumer Rights Act 2015, but proving its terms is another matter, and checking a contractor's credentials takes twenty minutes and rules out most chancers.

• •1. Write the schedule of works, and get any survey or engineer's input done first.
• •2. Longlist six: two from neighbours with comparable work, two from TrustMark or the Federation of Master Builders, two from the relevant trade body.
• •3. Send all six the identical schedule and drawings, with your realistic start window.
• •4. Filter to three or four who reply within a week with sensible questions. Slow, vague and over-eager all mean the same thing.
• •5. Walk each round yourself. A good old-house builder checks the airbricks, drain gullies and ceiling line before he looks at your kitchen.
• •6. Check registration, public liability of at least £2m and employers' liability of £5m if they have staff.
• •7. Take two references and view the work, ideally on a house of similar age. Ask the owner what went wrong and how it was handled.
• •8. Compare quotes line by line against your schedule. Anything missing is a variation waiting to happen.
• •9. Sign a written contract — JCT Home Owner or the FMB equivalent — with start and completion dates, stage payments against completed work, 2.5-5% retention and a named site contact.

Ask every candidate four questions and listen hard. How would you make good this lath and plaster ceiling? 'Bonding and multi-finish' is honest for a 1980s house and wrong here — you want haired lime or NHL 3.5, from someone who can explain why gypsum over damp solid brick fails. What would you insulate these walls with? If cavity wall insulation is mentioned, stop: a solid nine-inch wall has no cavity, and internal insulation done badly pushes the dew point into the plaster.

Repair or replace these sashes? Brush-seal draught-proofing costs £150-£350 a window and outlasts a cheap replacement. And what do you expect under the floor? A pre-1919 answer mentions clay drains, root ingress and shared laterals; a modern answer mentions nothing. Wiring needs its own conversation: rubber-sheathed cable, unearthed lighting circuits and a rewireable fuse box mean a full rewire, not a board swap — £4,000-£7,000 on a three-bed terrace, more where lath comes down and goes back in lime. Read what goes wrong in 100-year-old houses so you can tell a specialist from an optimist.

Never pay a large sum up front. A deposit for made-to-order items is reasonable; 40% before a spade goes in is not. Pay part of any deposit over £100 by credit card, because Section 75 of the Consumer Credit Act makes the provider jointly liable up to £30,000. And ignore anything you read about lien waivers — no construction lien exists over a private home here.

• •Programme slipping: ask for a revised written programme, not a verbal reassurance. Two missed dates without explanation is a pattern.
• •Price creep: every variation priced and signed before it is carried out. Retrospective variations turn a £30,000 job into £41,000.
• •Poor workmanship: a dated snag list with photographs, a fair period to fix it, and withhold retention only — withholding a whole stage payment can put you in breach.
• •No Building Control sign-off: chase the completion certificate before final payment, or you will buy indemnity insurance when you sell.
• •Deadlock: the TrustMark or FMB dispute scheme, then small claims up to £10,000. A contract agreed in your home also carries a 14-day cancellation right, extending to twelve months if you were never told of it in writing.

Managing trades yourself works when the job is sequential and small: a bathroom, a set of windows, a re-roof. Once three or more trades overlap, or the work touches structure, drainage or historic fabric, the 15-25% a main contractor charges is cheaper than the delays you cause learning on the job. Over about £60,000, or on any listed building, add a contract administrator.

There is also a harder line. Do not attempt gas work, open a live consumer unit, prop anything structural or disturb suspected asbestos. Knowing which corner is not yours to cut is the most valuable thing a homeowner brings to a project, and the warning signs a contractor is wrong for the job are the last check worth making before you sign.