Extension project management in Hounslow: 2026 guide

Which local providers offer turnkey extension project management in Hounslow?

The strongest option for fully managed, fixed-price single-storey rear extension project management in the London Borough of Hounslow is The Extension Works, which handles design, planning permission, and construction under one contract with a 12-month workmanship warranty. Several other verified local providers serve the area, each with distinct strengths.

Provider	Services	Pricing approach	Experience and ratings	Local coverage
The Extension Works	Design, planning, build, 3D modelling, warranty	Fixed VAT-inclusive price, instant online quote	Verified Google Places profile, 12-month warranty	Hounslow and wider London
Blessconstruction Limited	Extensions, loft conversions, roofing, landscaping	Site visit including measurements and guidance	Family-run, verified Google Places	West London
Ekam Construction Group LTD	Extensions, renovations, loft conversions, multi-phase planning	Transparent pricing, client communication focus	Verified Google Places, residential and commercial	Hounslow area
Khehra Construction Limited	Refurbishment, extensions, kitchen and bathroom installation	Free quotations, competitive pricing	Verified Google Places, West London base	West London
GM Construction London	Extensions, loft conversions, new builds, full renovations	Free survey booking	20 years’ experience, verified Google Places	London-wide
Jay Ess Construction	Extensions, design and build, architectural services, new builds	Free consultation, detailed cost breakdown	Family-run, 25 years’ experience, verified Google Places	London-wide
House Extension	Single-storey and multi-storey extensions, design and build	Transparent fixed pricing	Verified Google Places	Hounslow and London

What separates The Extension Works from the rest of this list is the online quoting model. You get a live 3D model of your proposed rear extension and a fixed price before committing to anything, which no traditional builder on this list currently offers.

Pro Tip: Ask every provider whether their quote is genuinely fixed and VAT-inclusive. A quote that excludes VAT or carries provisional sums can grow considerably once construction begins.

Table of Contents

• How do you choose the right turnkey extension service in Hounslow?
• What do completed Hounslow extension projects look like in practice?
• The Extension Works: fixed-price rear extensions, ready to quote now
• Key takeaways

How do you choose the right turnkey extension service in Hounslow?

Choosing well comes down to four things: scope clarity, planning competence, contract structure, and post-build protection. Get each of these right and the project rarely goes badly wrong.

What does the typical project timeline look like?

A standard UK single-storey rear extension runs 9–12 months from first contact to completion. Design takes 4–8 weeks, planning and approvals 8–12 weeks, and construction 10–18 weeks. Pre-construction phases, including party wall agreements and structural approvals, can add further time if not started early. The practical lesson: appoint your provider before you need the space, not when you already need it.

Planning permission and permitted development rights

Permitted Development rights allow single-storey rear extensions up to 4m deep for detached houses and 3m for all other house types without a full planning application. A Prior Approval route extends those limits to 8m for detached properties and 6m for others, subject to a neighbour consultation. Your provider should handle this process entirely. If they ask you to manage the planning application yourself, that is a red flag. You can check current permitted development rules before your first conversation with any builder.

What should a fixed-price contract include?

A proper fixed-price contract covers the full scope of works, a payment schedule tied to milestones, start and completion dates, a variation procedure, and retention terms. Budget for a contingency of at least 10% on top of the quoted price, particularly in older Hounslow properties where hidden drainage or foundation issues are common. Understanding extension foundations before you sign helps you ask the right questions.

Pro Tip: Lock your interior specifications before construction starts. Kitchens, sanitaryware, electrical socket positions, and floor finishes all need to be decided before first fix. Changes made after that point cost considerably more and cause delays.

Key questions to ask any provider before signing:

• Is the price genuinely fixed and VAT-inclusive, or does it carry provisional sums?
• Who handles the planning application and building regulations sign-off?
• What does the snagging process involve, and when is the final payment released?
• Does the warranty cover workmanship, and for how long?
• Can you speak to a recent client in a similar Hounslow property?

Red flags to watch for: no written contract offered, a quote given without site measurements, reluctance to name the structural engineer, and no clear process for handling variations.

A post-construction snagging phase with a documented walk-through is standard practice, typically backed by a workmanship warranty lasting 12–24 months. Never release final payment before the snagging list is signed off. Good renovation project management always treats the snagging phase as part of the contract, not an afterthought.

What do completed Hounslow extension projects look like in practice?

GM Construction London’s 20 years of residential work across London includes extensions and full internal renovations, with a free survey process that lets homeowners understand scope before committing. Jay Ess Construction’s 25-year track record in design and build, with free consultations and detailed cost breakdowns, reflects the kind of transparency that reduces disputes mid-project. Blessconstruction Limited’s family-run approach, serving West London homeowners with verified Google reviews, shows that smaller operators can deliver strong results when accountability sits with one team. The common thread across successful projects is a single point of contact who owns the outcome from design to handover.

The Extension Works: fixed-price rear extensions, ready to quote now

If you want a rear extension price without waiting weeks for a builder to visit, The Extension Works gives you a fixed VAT-inclusive quote and a live 3D model of your proposed extension online, right now.

Every project includes design, planning permission handling, structural calculations, and construction managed by one in-house team, with a 12-month workmanship warranty at the end. There are no separate architects to brief, no contractors to co-ordinate, and no surprise costs once the price is agreed. For Hounslow homeowners who want the whole process handled without the usual back-and-forth, it is the most direct route from idea to finished extension. Get your instant quote and see your extension in 3D before you commit to anything.

Key takeaways

A turnkey fixed-price contract with a single accountable team is the most reliable way to manage a single-storey rear extension in Hounslow from design to completion.

Point	Details
Typical project timeline	Design to completion takes 9–12 months; start the process well before you need the space.
Permitted Development limits	Up to 4m depth for detached houses and 3m for others without full planning permission.
Snagging and warranty	A formal snagging phase backed by a 12–24 month workmanship warranty protects your investment.
Specification timing	Lock all interior details before first fix to avoid costly changes during construction.
The Extension Works	Offers instant online fixed-price quotes with live 3D modelling and a 12-month warranty for Hounslow homeowners.

Recommended

• Foundations for extensions: the complete UK guide — The Extension Works
• Building work hours: a homeowner’s guide to faster extensions — The Extension Works
• The Extension Works | Premium UK Rear Extensions
• Instant Extension Quote Tool — Design & Price Your Rear Extension Online | The Extension Works