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TW3 · TW4 · TW5 · TW7

BuilderrinHounslow.

West borough with mix of Victorian terraces (Chiswick) and 1930s semis.

Quick answer

Builderr delivers loft conversions, side returns and rear extensions across Hounslow — TW3, TW4, TW5, TW7, TW8, TW13, TW14 and W4 — covering Chiswick (W4) Victorian terraces, Isleworth and Brentford riverside stock, and 1930s semis in Heston and Cranford. Chiswick is conservation-heavy and requires full planning; outer Hounslow retains strong PD rights for lofts and rear extensions.

About the area

Local context for Hounslow builds.

Hounslow covers postcodes TW3, TW4, TW5, TW7, TW8, TW13, TW14, W4. We've delivered residential construction projects across nearly every street here since 2022 — loft conversions, side-return and rear extensions, double-storey extensions, kitchen and bathroom renovations, full whole-house refurbishments, and a small number of new-build infill homes.

West borough with mix of Victorian terraces (Chiswick) and 1930s semis. Our local project manager for this borough has detailed knowledge of the planning department's preferences, the conservation area boundaries, the common construction details for the prevailing housing stock, and which side streets accept skip permits without issue.

Quotes for Hounslow projects are fixed-scope after a site survey, valid for 60 days, and never carry provisional sums or open-ended day rates. Every project includes our 10-year structural warranty and 12-month defects period.

Build types in Hounslow

Specialised types popular here.

Dormer Loft Conversion
Dormer Loft Conversion in Hounslow

The London standard. Rear dormers add a full-height bedroom + ensuite under permitted development on most terraces.

Mansard Loft Conversion
Mansard Loft Conversion in Hounslow

The premium loft. Vertical rear wall + 70-degree slate roof. Maximum floor area on Georgian and Victorian terraces.

Hip-to-Gable Loft Conversion
Hip-to-Gable Loft Conversion in Hounslow

The semi-detached upgrade. Replace the hipped side roof with a vertical gable wall to unlock a full dormer behind.

L-Shape Loft Conversion
L-Shape Loft Conversion in Hounslow

The Victorian terrace specialist. Build a dormer over both the main roof and the rear closet wing for two bedrooms + bathroom.

Velux Loft Conversion
Velux Loft Conversion in Hounslow

The cheapest, fastest loft. Insulate the existing roof, install rooflights, and add a fire-rated stair — no roof alteration.

Side Return Extension
Side Return Extension in Hounslow

The classic kitchen-diner extension. Fill the side alley of a Victorian terrace for a 3–4m wider open-plan kitchen.

Rear Extension
Rear Extension in Hounslow

Extend the back of the house up to 6m under the prior approval route. Open-plan kitchen-diner with garden views.

Wraparound Extension
Wraparound Extension in Hounslow

Side return + rear extension combined into one L-shape ground floor. Largest single-storey footprint without going double-storey.

Double-Storey Extension
Double-Storey Extension in Hounslow

Two floors of extension — bigger kitchen below, extra bedroom + bathroom above. The full upsize without moving.

Kitchen Extension
Kitchen Extension in Hounslow

Extension build plus full kitchen fit-out in one fixed-price project. Open-plan kitchen-diner with bifold doors and roof lantern.

Integral Garage Conversion
Integral Garage Conversion in Hounslow

Convert an attached garage to a bedroom, office or living room. No new foundations or external walls. From £25,000 in 4–8 weeks.

Detached Garage Conversion
Detached Garage Conversion in Hounslow

Transform a detached outbuilding into annexe, home office, studio or garden room. Independent from main house, own entrance.

Load-Bearing Wall Removal
Load-Bearing Wall Removal in Hounslow

Open up your ground floor — steel beam install, structural calcs, building regs and party wall, fixed-scope.

RSJ Installation
RSJ Installation in Hounslow

Steel beam supply and install for openings, extensions and structural alterations — engineer-signed, building-regs certified.

Underpinning
Underpinning in Hounslow

Strengthen existing foundations — for subsidence repair, basement excavation or load increase. Engineer-led, building-regs compliant.

Cellar Conversion
Cellar Conversion in Hounslow

Convert your existing under-house cellar into a habitable home office, utility, gym or guest room — no excavation needed.

Full Basement Excavation
Full Basement Excavation in Hounslow

Create a new basement under your existing house — full excavation, underpinning, waterproofing and habitable fit-out.

Basement Extension
Basement Extension in Hounslow

Add basement floor area beyond the existing house footprint — sub-garden excavation with light wells for cinema, gym, spa.

Planning in Hounslow

Local planning rules and conservation areas.

Hounslow's conservation areas include Chiswick (Bedford Park, Old Chiswick, Strand-on-the-Green, Glebe Estate), Brentford Town Centre, Isleworth Riverside, Spring Grove and parts of Hanworth. Article 4 directions cover Bedford Park and the Glebe Estate. Outside Chiswick, the borough is moderately planning-friendly with PD rights retained on most semi stock. Heston, Cranford and Hanworth see high prior approval rates for larger rear extensions and hip-to-gable lofts.

Every quote we issue for Hounslow includes a free desk-based planning assessment of your specific address — we tell you whether your project is permitted development, prior approval, or full planning before you sign anything. Our planning team handles the full submission including drawings, Design and Access Statements, and pre-application consultation where required.

Compare

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.

Builderr fixed price
£120,000
a Hounslow project · no provisional sums
Typical builder + variations
£144,000
+£24,000 vs Builderr (≈20% overrun)
Cowboy outfit + cost creep
£174,000
+£54,000 vs Builderr (≈45% overrun)
CriterionBuilderrTypical London builderCowboy outfit
Labour modelDirectly employed team (PAYE)Mixed subcontract gangsDay-rate cash labour
PricingFixed-scope itemised quoteEstimate + provisional sumsVerbal price + variations
Design & engineeringIn-house architect + SEOutsourced, separate billingBuilder draws on the back of an envelope
Planning + LDC handledYes — included in priceOften charged extraBuilder asks you to apply
Party wall surveyorsInstructed by usYour responsibilitySkipped (illegal)
Building controlPlans + site inspections booked by usBuilding Notice routeNot registered
Project managementDedicated PM, weekly photo updatesForeman doubles upOwner-manager juggles 5 jobs
Payment scheduleStage payments against signed-off milestonesWeekly invoicesCash up front
Insurance£10M PL + 10yr structural warranty£2–5M PL onlyNo documented cover
Snags at handover<3 typical20–30 typicalWalk-off mid-job common
Variation creep0% — fixed scope+15–25% over original quote+40%+ regularly
Bottom line

Save £24,000£54,000 on a Hounslow 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 £120,000.

FAQ

Hounslow questions, answered.

Do you cover all of Hounslow?+

Yes — every postcode within Hounslow is within our standard coverage zone. We've delivered projects in nearly every postcode of the borough since 2022.

How do planning rules differ in Hounslow?+

Hounslow's planning authority maintains a local plan and conservation area register that differ from the national permitted development baseline. We run a free desk-based planning assessment of your address before quoting so you know whether your project is PD or needs full planning.

How long does a typical Hounslow project take?+

Bathroom renovations 2–5 weeks, kitchen renovations 3–8 weeks, loft conversions 8–14 weeks, single-storey extensions 10–18 weeks, double-storey or wraparound extensions 16–22 weeks, full house renovations 16–36 weeks. Programme is fixed at contract sign and tracked weekly.

Do you have references in Hounslow?+

Yes — we maintain a live reference list per borough. We can connect you with two or three completed clients in Hounslow for an unfiltered conversation about working with us.

Ready to build in Hounslow?

Senior consultant call within one business hour. Free desk-based planning assessment for TW3, TW4, TW5 and surrounding postcodes.