How we work
Fromestimatetohandoverinonetransparentprocess.
Ten distinct stages. Every one has a defined timeline, deliverable and price. You always know what's next, who's responsible, and what it costs.
Same day
Online estimate — 60 seconds
Start with our online quote engine. Pick your project type — loft conversion, side return extension, kitchen renovation, double-storey extension, full house refurbishment, new build — then select size (small, medium, large) and planning status (permitted development, prior approval, full planning). The engine returns an indicative cost range and timeline within seconds, calibrated against our last 100 completed projects. No commitment, no email gate. The estimate becomes the working assumption for the next stage.
In detail
Our cost engine pulls from a database of 847 completed Builderr projects. We update the multipliers monthly with material price movements, labour cost inflation, and borough-specific planning fee changes. The range you see covers the 25th to 75th percentile of comparable projects — about half come in below the midpoint, half above. Outliers (unusual structural conditions, premium specifications, conservation-area complexity) sit outside the band and we'll flag those at survey.
2 hours on site
Site survey — within 5 working days
A senior project consultant visits your property. We measure existing rooms, check ceiling and ridge heights, photograph the rear elevation, inspect the foundations through trial holes where accessible, and confirm party wall conditions. The survey takes 1.5 to 2 hours typically and produces a single PDF report with measured drawings, condition photos, and an updated cost range now calibrated to your specific property rather than the generic estimate.
In detail
On a typical loft survey we measure floor-to-ceiling heights at six points across the loft (front, centre, rear, both sides, ridge), check the structural condition of existing ceiling joists, identify chimney stack positions, verify roof pitch with a smart angle gauge, and photograph every elevation. On a side return survey we additionally check soil pipe routing, gas meter location, water mains entry, and electrical incoming. The survey output feeds directly into the design brief.
Concept + planning pack
Design & drawings — 3 to 6 weeks
Our in-house architect produces a concept design, then a developed design, then planning drawings. You see the concept within 10 working days of survey and provide feedback. The developed design follows 2 weeks later. Planning drawings (1:100 site plan, 1:50 floor plans, 1:50 elevations, 1:20 details where relevant) are prepared for submission. Structural calculations run in parallel, prepared by our chartered structural engineer.
In detail
Concept work uses SketchUp 3D models with V-Ray rendering so you see exactly what the finished space will look like — daylight at 8am, 12pm and 4pm; furniture layouts; glazing reflections. We test alternate layouts at this stage: island position, stair direction, ensuite vs separate bathroom, bifold vs slider vs Crittall. Once concept is locked, planning drawings are produced in AutoCAD to the standard each London borough requires. Structural calculations cover steel beam sizes, foundation depths, and loading paths.
Borough-managed
Planning submission & approval — 8 to 12 weeks
We submit your planning application, lawful development certificate or prior approval. For full planning we include a design and access statement, heritage impact assessment in conservation areas, daylight/sunlight study where appropriate, and pre-application meeting notes. Our planning approval rate is 88% first-time on full applications and 94% on permitted development LDCs. We handle any officer queries, neighbour consultations and amendments without billing extra.
In detail
For permitted development extensions we submit a Lawful Development Certificate alongside the build — this is your legal proof that the work falls under PD, valuable on resale and required by most mortgage lenders. For prior approval (Larger Home Extension scheme, 3-6m terrace, 3-8m detached) we manage the 21-day neighbour consultation period and respond to any objections. For full planning, our standard pack includes everything required by the borough plus extras most contractors skip: 3D massing studies, photographic context, materials sample boards.
Parallel to planning
Party wall — 4 to 6 weeks
Where works affect a party wall (almost every London terrace project), we serve formal party wall notices on your neighbours under the 1996 Party Wall Act. We instruct an agreed surveyor where neighbours consent, or appoint two surveyors where they prefer separate representation. Schedules of condition are produced on neighbouring properties. Awards are drafted, agreed and recorded. Without this, any work you do to a shared wall is technically illegal — most cowboy outfits skip it; we never do.
In detail
On most loft conversions we serve notice under Section 1 (line of junction) and Section 6 (excavation within 3m or 6m). On extensions we typically serve Section 1, 2 (party wall works) and 6. Our party wall surveyor panel includes Bowker Sadler, Peter Barry and Jonathan Stuart — three of London's most respected practices. We pay the surveyor fees on your side; you pay the neighbour's surveyor (typically £1,500 to £2,500 per neighbour) as is legally required.
Itemised, no surprises
Fixed-scope quote — 1 week
With planning approved and structural drawings finalised, we produce the final fixed-scope quote. Every line is itemised: foundations by cubic metre, steels by section size, glazing by manufacturer and unit, kitchen by supplier and cabinet count. PC sums (where you choose final products like bathroom suites, kitchen worktops, tiles) are transparent with allowances against a defined spec. The price you sign is the price you pay. Variations require your written agreement before any work happens.
In detail
Our quote pack runs to 25–40 pages typically. Cover sheet with summary cost and key dates. Scope sheet listing inclusions and exclusions. Itemised pricing schedule. PC sum schedule with example products. Drawing register. Gantt chart with every site phase. Payment schedule (stage payments against signed-off milestones — never weekly invoices). Variation procedure. Defects liability period (12 months from practical completion). Insurance and warranty schedule.
Logistics & ordering
Pre-start — 2 weeks before site
Two weeks before the start date, we hold a pre-start meeting. We confirm the start date, scaffolding installation day, skip delivery, parking permits, neighbour notifications, working hours (8am–5pm Monday to Friday, 9am–1pm Saturday, no Sundays), waste removal schedule, and noise restrictions specific to your borough. Materials are ordered with delivery timed to phase. Long-lead items (Crittall doors, bespoke joinery, structural steels) are placed weeks earlier.
In detail
Camden, Westminster, Kensington & Chelsea, Islington, City of London and Tower Hamlets have noise restrictions tighter than the standard 8am–5pm — typically 9am–6pm or with mid-day breaks. We comply with whatever your borough mandates. Parking suspensions are arranged through your council's online portal; cost is typically £20–40 per bay per day. Skip permits run £30–50 depending on borough.
Weekly photo updates
Site build — typically 8 to 22 weeks
Your dedicated project manager runs the build day-to-day. The site team is the same five to eight people from start to finish — directly employed Builderr trades, never subcontracted. You get weekly photo and video updates to a private project portal. We hold a weekly progress meeting (typically Friday morning) — in person on site or via video call, your choice. Building control inspections are booked by us at every required milestone.
In detail
Typical build phasing on a loft conversion: week 1 scaffold + roof open; week 2 structural steels + new floor; week 3 dormer carcass + roof finish; week 4 windows + external cladding; week 5 first fix electrics + plumbing; week 6 insulation + plasterboard; week 7 plaster + second fix; week 8 finishes + decoration; week 9 final fix + snagging; week 10 building control sign-off + handover. Side return extensions add 4-6 weeks for foundations, brickwork and glazing.
Zero-snag target
Handover & sign-off — final week
Building control issues the Final Certificate confirming compliance. We walk the project with you, snag list in hand. Any snags identified are completed before final payment. We hand over the warranty pack: structural warranty certificate, manufacturer warranties for windows, doors, kitchen, bathroom fittings, heating system, and electrics. Plus the building log book — every drawing, certificate and approval indexed for resale.
In detail
Our handover pack runs to 80–120 pages typically. Building control Final Certificate. Structural warranty (10-year, NHBC or LABC). FENSA or CERTASS certificate for windows. Part P electrical certificate. Gas Safe certificate for any gas work. EICR (Electrical Installation Condition Report). MVHR commissioning certificate if installed. Manufacturer warranties (transferable). Operating and maintenance manuals. As-built drawings. Snag list signed-off. Defects liability period start date.
Lifetime relationship
Aftercare — 12 months defects + 10 year warranty
Twelve months from handover is the defects liability period. Any latent defects — settlement cracks, sticking doors, loose tiles, minor finish issues — we return and fix free of charge. We schedule a six-month and twelve-month walk-through proactively. Beyond that, the 10-year structural warranty covers major structural defects. We also remain available informally — most clients call us five or six years later for top-up work, second projects, or recommendations.
In detail
Our defects callback rate during the 12-month period averages 4.3 items per project. Most are minor: paint touch-ups where furniture has scuffed walls, hairline settlement cracks at plaster junctions (normal for any new build), door alignment as timber relaxes, sealant replacement at high-movement joints. We attend within 5 working days of report. Emergencies (water ingress, structural concern, electrical fault) get same-day attendance.
What's included
Everything you'd expect to be in a quote. Nothing pretending to be a bonus.
Builderr vs other London builders.
The construction industry has a wide distribution of operators. Here's what changes between a directly-employed, fixed-scope outfit and the alternatives.
| Criterion | Builderr | Typical London builder | Cowboy outfit |
|---|---|---|---|
| Labour model | Directly employed team (PAYE) | Mixed subcontract gangs | Day-rate cash labour |
| Pricing | Fixed-scope itemised quote | Estimate + provisional sums | Verbal price + variations |
| Design & engineering | In-house architect + SE | Outsourced, separate billing | Builder draws on the back of an envelope |
| Planning + LDC handled | Yes — included in price | Often charged extra | Builder asks you to apply |
| Party wall surveyors | Instructed by us | Your responsibility | Skipped (illegal) |
| Building control | Plans + site inspections booked by us | Building Notice route | Not registered |
| Project management | Dedicated PM, weekly photo updates | Foreman doubles up | Owner-manager juggles 5 jobs |
| Payment schedule | Stage payments against signed-off milestones | Weekly invoices | Cash up front |
| Insurance | £10M PL + 10yr structural warranty | £2–5M PL only | No documented cover |
| Snags at handover | <3 typical | 20–30 typical | Walk-off mid-job common |
| Variation creep | 0% — fixed scope | +15–25% over original quote | +40%+ regularly |
Save £20,000–£45,000 on a typical London project.
Industry data (FMB, RICS, Which? Trusted Trader 2024) shows the average London construction project overruns by 18–22% on cost and 25–35% on time. Fixed-scope contracts with a single accountable team eliminate that variance. The savings above assume a typical project at £100,000.
Next
Ready to start at step 1?
Get your indicative online estimate in 60 seconds. Then book the site survey at your convenience.
Start your project today.
Senior consultant call within one business hour. Free desk-based planning assessment. Then we move you through steps 1 to 10.
