Question 1

How much does a loft conversion cost in London?

Accepted Answer

In 2026 a standard dormer loft conversion in London typically costs £55,000-£90,000. A mansard (full-rear, vertical wall) sits at £80,000-£110,000, and an L-shaped dormer on a Victorian terrace is usually £75,000-£105,000. Prices vary with finish level, en-suite complexity, structural steels and party-wall requirements. A free site visit and full drawings are required for a binding quotation.

Question 2

Do I need planning permission for a loft conversion?

Accepted Answer

Most dormer loft conversions fall under Permitted Development (PD) provided the volume added does not exceed 40 cubic metres (terraced) or 50 cubic metres (detached/semi). PD does not apply in conservation areas, to listed buildings or to flats. A mansard almost always requires full planning permission. We always recommend obtaining a Lawful Development Certificate even when PD applies.

Question 3

How long does a loft conversion take?

Accepted Answer

A standard rear dormer takes 8-10 weeks on site. A mansard or L-shaped dormer typically takes 10-14 weeks. Add 4-8 weeks before site start for architectural drawings, structural calculations, Building Control application and party wall notices (if applicable). The total programme from instruction to handover is usually 16-22 weeks.

Question 4

Do I need planning permission for a rear extension?

Accepted Answer

In most cases a single-storey rear extension up to 6 metres (terraced/semi) or 8 metres (detached) is covered by Permitted Development under the Neighbour Consultation Scheme - no full planning is needed but you must apply for Prior Approval. Two-storey rear extensions, conservation areas, listed buildings and many flats always need full planning permission. A Lawful Development Certificate is strongly recommended even for PD-covered work.

Question 5

How much does a single-storey rear extension cost?

Accepted Answer

In Greater London and the South East a single-storey rear extension typically costs £2,200-£2,800 per square metre for the shell and £3,000-£3,800/m2 fully finished including kitchen or utility fit-out. A typical 4m x 6m (24m2) extension runs £70,000-£95,000 all-in. Prices vary with ground conditions, finishes and whether you are extending under Permitted Development or full planning.

Question 6

What is the cheapest type of extension?

Accepted Answer

A single-storey rear extension under Permitted Development is almost always the most cost-effective because it avoids full planning fees, tends to have simpler foundations and does not require a new roof structure. Side-return infills on Victorian terraces also offer excellent value per square metre because you are building within existing walls on two sides.

Question 7

How long does a house refurbishment take?

Accepted Answer

A full strip-out refurbishment of a 3-bed terrace typically takes 12-16 weeks on site, plus 2-4 weeks of design and procurement upfront. A flat refurbishment is usually 8-12 weeks. Add 4-8 weeks if the works include structural alterations (steel beams, opening up) or a kitchen extension running in parallel.

Question 8

How much does a full house refurbishment cost in the UK?

Accepted Answer

A full refurbishment (new electrics, plumbing, heating, plastering, kitchen, bathrooms, decoration) typically costs £1,200-£1,800 per square metre in Greater London. For a 90m2 3-bed terraced house that is roughly £110,000-£160,000. High-end finishes, structural work and layout changes push the upper end. We always provide a fixed written quotation after a site visit.

Question 9

What does a refurbishment include vs a renovation?

Accepted Answer

A refurbishment is a comprehensive strip-out and rebuild of the internal fabric - all first-fix services (electrics, plumbing, heating), plastering, flooring, kitchens and bathrooms are replaced. A renovation is typically lighter: cosmetic updates, painting, new flooring and possibly one or two new rooms. If your property has original wiring, lead pipes or is generally tired throughout, a full refurbishment is usually more cost-effective than patching.

Question 10

How much does it cost to remove a load-bearing wall?

Accepted Answer

Removing a load-bearing wall and installing a steel beam (RSJ) typically costs £3,500-£8,000 in London, depending on the span, beam size, number of temporary supports (Acrows) and floor type. The structural engineer's calculation is usually £400-£800 and Building Control notification is required. Wider openings (over 3.5m) or openings near party walls cost more due to padstone and bearing requirements.

Question 11

Do I need Building Control approval for structural work?

Accepted Answer

Yes - all structural alterations require a Building Control application. This includes removing load-bearing walls, installing steel beams, creating new openings, underpinning and changes to floor or roof structure. RCB lodges the application on your behalf at the start of every project; fees are typically £400-£1,200 depending on the council and the project value.

Question 12

What is underpinning and when is it needed?

Accepted Answer

Underpinning strengthens or deepens existing foundations. It is needed when foundations are too shallow for a new extension (common on pre-1960s properties), when subsidence has damaged the structure, or when you are excavating a basement. Traditional mass concrete underpinning costs £1,500-£3,000 per linear metre. Mini-piled underpinning (for deeper or more complex cases) costs £2,500-£5,000 per pile.

Question 13

What insurance should my builder have?

Accepted Answer

A reputable UK contractor carries (a) Public Liability of at least £5 million, (b) Employer's Liability of £10 million (legally required if they employ anyone), (c) Contract Works insurance covering the project itself, and (d) Professional Indemnity if they provide design. Ask for copies of certificates before signing. RCB Design & Build is FMB, TrustMark, Checkatrade and TrustATrader accredited with full cover.

Question 14

What is a scope of works in construction?

Accepted Answer

A scope of works (SoW) is the line-by-line document that defines exactly what the contractor will and will not do - every trade, every material, every inclusion and every exclusion. A good SoW prevents 95% of the disputes that happen on residential projects. RCB issues a full SoW with every estimate over £15,000 and shares it with the client to review before pricing is added.

Question 15

How much does scaffolding cost in London?

Accepted Answer

For a typical 3-bed semi a rear scaffold (loft conversion or rear extension) costs £1,800-£3,500 for the first 4 weeks plus £150-£300 per week extension. A full-wrap (whole-house) scaffold for re-roofing or render is usually £3,500-£7,000. Pavement licences (if scaffolding sits over the public highway) add £200-£600 depending on borough.

Question 16

Do I need a party wall agreement?

Accepted Answer

You need a Party Wall Notice (and almost always an Award) if you are cutting into, building on or excavating within 3 metres of a shared wall, or excavating within 6 metres if foundations go deep. Most loft conversions, side extensions and structural opening-up trigger it. Allow 2 months for the process and £900-£2,000 per neighbour in surveyor fees.

Question 17

What is Building Control and when do I need it?

Accepted Answer

Building Control inspects structural, fire, energy and safety compliance under the Building Regulations. You need a Building Control application for almost any structural work - extensions, loft conversions, structural openings, new bathrooms, electrical alterations (Part P), drainage changes and most insulation upgrades. RCB lodges the application on your behalf at the start of every project; fees are typically £600-£1,800 depending on the council and the project value.

Question 18

What warranty do I get on building work?

Accepted Answer

RCB provides a 2-year defects liability period (DLP) on all projects as standard. During this period any defects in workmanship or materials are rectified at no cost. Structural work carries a 10-year structural warranty (available via LABC Warranty, Premier Guarantee or similar) which is essential if you plan to sell or remortgage. Manufacturer warranties on boilers, windows and kitchens typically run 5-10 years independently.

Question 19

What materials does RCB use as standard?

Accepted Answer

Our standard specification includes ceramic tiles (300x300mm minimum), laminate flooring (no carpet - RCB does not install carpet but will remove existing). Second-fix materials such as sanitaryware, tiles and decorative fittings are client-supplied items chosen to your taste and budget. We provide a procurement schedule and can advise on suppliers. First-fix materials (timber, steel, plumbing, electrics) are contractor-supplied to Building Regulation standard.

Question 20

How does the payment schedule work?

Accepted Answer

RCB operates on a stage-payment basis. The deposit is 5% of the contract value, payable on acceptance. Subsequent payments are tied to completed milestones - typically: strip-out complete, first-fix complete, plastering complete, second-fix complete, and final account on practical completion. Each stage is signed off before payment is due. We never ask for large upfront payments.

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