Where to Start With a Home Renovation in London: A Step-by-Step Guide

Before any professional is involved, the homeowner needs to answer one question clearly: what does 'done' look like?

• This sounds obvious, but most people begin with a vague aspiration — 'we want to improve the kitchen' or 'we want more space' — without defining what that means practically. The problem is that 'improve the kitchen' could mean:
• •Replace the kitchen units and worktops in the existing space: £8,000–£18,000 building works
• •Open up the existing kitchen to the dining room (structural alteration + kitchen): £20,000–£35,000
• •Extend the rear and create a new open-plan kitchen-diner: £65,000–£110,000
• •Extend, open up, and add a loft conversion: £130,000–£190,000

These are not the same project. Starting with clarity about the outcome — number of rooms, how the space should function, what the property needs to be worth at the end — allows every subsequent decision (budget, architect brief, contractor selection) to be made rationally.

• **Questions to answer before calling anyone:**
• •Which rooms are you improving, and why?
• •What will each room be used for when the project is done?
• •Are you adding space (extension/loft) or reconfiguring existing space?
• •Do you need more bedrooms, or better living space, or both?
• •Is this a long-term home or an investment to sell?
• •When does the project need to be complete?
• •Are you living in the property during works, or vacating?

The second critical step — before talking to an architect, before getting quotes — is establishing what you can realistically spend.

The reason this must come before the architect is that design naturally expands to fill the available aspiration. Without a budget constraint, an architect will design the ideal project. The ideal project will be larger and more complex than your budget allows. You will then spend money on drawings for a project you cannot afford to build.

**How to establish a budget:** 1. Determine what funds are available (savings, equity release, remortgage capacity) 2. Add a contingency of at least 15–20% on top of the expected construction cost 3. Allow for professional fees: architect (8–15% of construction cost), structural engineer (£1,500–£5,000), party wall surveyor (£1,500–£4,000), Building Control (£500–£1,500), planning fees (£258+ if needed) 4. Allow for any temporary accommodation or storage costs during works 5. Allow for furniture and finishes at the end (kitchen, flooring, bathroom suites, lighting — all of which are separate from construction costs)

• **Budget reality check (London 2026):**
• •£30,000–£60,000: cosmetic whole-house refurbishment or a good bathroom + kitchen
• •£60,000–£100,000: full ground floor extension or a solid refurbishment + extension
• •£100,000–£160,000: wraparound extension or loft + refurbishment or combined ground floor project
• •£160,000–£250,000: major combined project — loft + extension + full refurbishment
• •£250,000+: the largest projects — major structural alteration, basement, or premium full-house rebuild

**Get a ballpark before getting drawings:** Many reputable contractors will provide an early-stage ballpark figure (a rough budget range) based on project type and scope, before any drawings are produced. This is useful for establishing whether the aspiration and the budget are aligned before spending money on an architect.

Before appointing an architect or going out to tender, understand the planning and regulatory position:

• **Planning permission:**
• •Is the property in a Conservation Area? (Check the council's website — it affects almost everything)
• •Are there existing Permitted Development rights, or has an Article 4 Direction removed them?
• •Has the PD allowance been used by previous extensions?
• •Is the property listed?
• •Have previous owners had planning permissions or enforcement notices?

The council's planning portal shows the planning history for any address. Spend 20 minutes researching this before doing anything else.

• **Building Regulations:**
• Almost all renovation work beyond pure decoration requires Building Regulations approval:
• •All structural alterations
• •All electrical work in kitchens and bathrooms
• •Replacement boilers, heating systems
• •Roof alterations
• •Extensions of any type
• •Conversions (loft, garage, basement)

**Party wall:** Any work within 3–6 metres of a neighbour's foundation, or to a wall shared with a neighbour, requires Party Wall Act notices.

**CDM 2015:** For any project lasting more than 30 working days, or involving more than 500 person-days of work, the HSE must be notified and a Principal Designer and Principal Contractor must be appointed.

For smaller projects (most domestic extensions and loft conversions), CDM 2015 still applies — duties are shared between the homeowner and the contractor.

**The correct order:**

1. **Project definition and budget** (you do this — before any professional) 2. **Ballpark cost check** (from a contractor or cost consultant — to confirm budget/aspiration alignment) 3. **Architect brief** (with budget confirmed, give the architect a constrained brief) 4. **Planning drawings** (architect produces drawings for planning or PD confirmation) 5. **Planning / LDC application** (wait 4–14 weeks depending on route) 6. **Technical design development** (architect + structural engineer + specialist consultants) 7. **Tender package** (full drawings, specification, schedule of works for pricing) 8. **Contractor selection and contract** (compare like-for-like quotes on full tender information) 9. **Party wall notices** (served on neighbours — allow 14 days minimum, sometimes longer) 10. **Building Control application** (Full Plans or Building Notice) 11. **Mobilisation and start on site**

**The most common mistake:** Appointing a contractor from a single quote before a full design package exists. Without a complete set of drawings and a specification, different contractors quote different scopes — the comparison is meaningless.

• **What a good contractor does before starting:**
• •Reviews the drawings with the structural engineer's input
• •Walks the site with the project lead
• •Provides a written scope of works and schedule of works
• •Issues a formal contract (JCT or bespoke domestic contract)
• •Confirms programme and milestone dates in writing
• •Clarifies what is included and excluded (particularly: client-supplied vs. contractor-supplied materials)

If a contractor will not do these things, that is a red flag.

The contractor selection decision is the most consequential in the project. The cheapest quote is rarely the best outcome.

• **What to check before appointing:**
• •Company registered at Companies House — check age, director history, and whether previous companies have been dissolved
• •Public Liability insurance (minimum £5m — ask for the certificate, not just the statement)
• •Employer's Liability insurance (if they employ people)
• •VAT registration (if the quote is significant, the contractor should be VAT registered — if they are not, ask why)
• •Membership of a trade body: a recognised trade body, RICS, CIAT, or similar
• •References from recent comparable projects: call the references, ask about communication, programme, and defects handling
• •a vetted contractor review platform review platform reviews — read them, look for patterns in negative reviews

• **Comparing quotes:**
• •Request quotes from at least three contractors on identical tender documentation
• •Where one quote is significantly lower, ask for an explanation — it may reflect missing scope, not efficiency
• •The contract must define: scope, programme, payment terms, variation procedure, defects liability period

• **Red flags:**
• •Cash only payment requests
• •Requests for large upfront payment before work begins
• •Pressure to start before a contract is signed
• •No fixed price for defined scope (a quote that is 'subject to change' before any variation)
• •Contractor who will not provide a written contract
• •No experience of comparable project types or London-specific regulations