Garage Conversions
London & Hertfordshire
Transform your underused garage into a beautiful, functional living space. TCM Building specialises in all types of garage conversion — from simple integral conversions to full detached annexes — across London and Hertfordshire.
The UK's Most Cost-Effective
Way to Add Living Space
A garage conversion is the process of transforming an existing garage — integral, attached, or detached — into a habitable room. It is widely regarded as the most cost-effective way to add usable floor area to a home, because the structure already exists. Unlike an extension, there are no new foundations to dig, no new external walls to build, and no new roof to construct.
Research consistently shows that fewer than 30% of UK garages are used for parking. The majority are used for storage — often of items that could be stored elsewhere. Converting that space into a home office, playroom, gym, or guest bedroom can transform the way a family uses their home.
TCM Building manages the entire garage conversion process — from the initial site survey and Building Regulations application through to plastering, electrical works, and final decoration. You deal with one team, one contract, and one point of contact throughout.
Which Type Applies to Your Garage?
Integral Garage Conversion
An integral garage is built within the footprint of the main house, typically beneath a bedroom or living room. This is the most common type of garage conversion in London and Hertfordshire, and the most straightforward to convert — the structure is already part of the house, so no new foundations or external walls are required. Most integral garage conversions can be completed under Permitted Development rights.
Popular Uses for Converted Garages
Additional Living Room
Create a separate snug, playroom, or TV room — giving the family more space without the cost of an extension.
Home Office
A dedicated, professional workspace away from the main house. The most popular use for garage conversions since 2020.
Home Gym
A private gym with rubber flooring, mirrors, and ventilation. No monthly membership fees, no commute.
Guest Bedroom / Annexe
Self-contained guest accommodation with an en-suite bathroom — ideal for visiting family or as an income-generating rental.
From Survey to Handover
Free Site Survey
We visit your property, assess the garage structure, and discuss your intended use. We advise on planning requirements and provide an indicative cost guide.
Design & Planning
We produce drawings showing the proposed layout, window positions, and door locations. We advise on Permitted Development vs. planning permission.
Building Regulations
All garage conversions require Building Regulations approval. We submit the application and manage the inspection process on your behalf.
Fixed-Price Quotation
We provide a fully itemised, fixed-price quotation covering all works — groundworks, insulation, services, plastering, and decoration.
Construction
Our team carries out all works — floor build-up, wall insulation, windows and doors, first-fix services, plastering, and second-fix.
Finishing & Handover
We complete all decoration and snagging before handover. Building Regulations sign-off is obtained and provided to you.
Garage Conversion Cost Guide
All prices are indicative for London and Hertfordshire. A fixed-price quotation is provided after the free site survey.
| Conversion Type | Typical Cost | Added Value | Build Time | Planning |
|---|---|---|---|---|
| Integral Garage | £10,000 – £25,000 | 10–15% | 3–6 weeks | Usually PD |
| Attached Garage | £12,000 – £30,000 | 10–15% | 4–7 weeks | Usually PD |
| Detached Garage | £18,000 – £45,000 | 8–12% | 6–10 weeks | May be required |
| Double Garage | £20,000 – £55,000 | 12–18% | 6–12 weeks | Often required |
PD = Permitted Development. All prices exclude VAT. Building Regulations approval is always required regardless of planning status.
Planning & Building Regulations
Understanding the regulatory requirements for a garage conversion is essential. Here's what you need to know.
Planning Permission
Building Regulations
TCM handles all planning applications and Building Regulations submissions on your behalf. We have an excellent track record of securing approvals and will guide you through the entire process.
Trusted Garage Conversion
Specialists
Structural, electrical, plumbing, plastering, and decoration — all managed by our team. No coordination headaches.
We handle all Building Regulations submissions and inspections, and provide you with the completion certificate.
Our quotations are fully itemised and fixed-price. What we quote is what you pay.
Independently verified on Checkatrade with a 5-star rating from over 100 verified client reviews.
"TCM converted our integral garage into a home office and it's transformed how we use our house. The whole project took just four weeks and the finish is immaculate. They handled all the Building Regulations paperwork too — completely stress-free."
Book a Free Site Survey
We'll visit your property, assess the garage, and provide a detailed quotation — completely free of charge.
It's frustrating when you need more room but feel stuck with your current layout. Maybe your garage is just a dumping ground, or perhaps it's never truly served its purpose. What if that underutilised space could become a vibrant part of your home, perfectly tailored to your needs? A garage conversion is simply transforming your existing garage structure into a functional, habitable room. We're talking about more than just tidying up; it's about reimagining that space as a new bedroom, a dedicated home office, a personal gym, or even an extended living area. It's a clever way to add significant value and usability to your property without the disruption and cost of a full extension. This matters because your home should work for you. A well-executed garage conversion solves common problems like lack of space, the need for a quiet workspace, or a desire for a dedicated hobby room. It's about making your home more comfortable, more efficient, and ultimately, a better fit for your life right here in Borehamwood.
You're probably feeling the squeeze at home, aren't you? Maybe the kids need more space, or you're trying to work from the kitchen table. You know you need a change, but you're not sure what the best solution is. Is it time to move, or is there a smarter way to get the extra room you desperately need without all the upheaval?
What You Need to Know
Seamless Integration & Design
We ensure your new space feels like it was always part of your home, not an afterthought. Our design team works with you to create a layout and aesthetic that perfectly matches your existing property and your personal style. We consider everything from natural light to flow, making sure your conversion enhances your home's overall appeal.
Expert Planning & Regulations
Navigating planning permission and building regulations can feel overwhelming, can't it? We handle all the complexities, from initial surveys to final approvals. Our team knows the local requirements in Borehamwood and Hertfordshire inside out, ensuring your project is fully compliant and stress-free from start to finish.
Quality Craftsmanship & Materials
Your garage conversion is an investment, and we treat it that way. We use only high-quality, durable materials and employ skilled tradespeople who take pride in their work. This means your new room won't just look great; it'll be built to last, offering comfort and functionality for years to come.
Everything Else You Should Know
Understanding Garage Conversion Costs
How much does a garage conversion really cost? It's a common question, and the answer depends on several factors like the size of your garage, the complexity of the design, and the finishes you choose. We provide clear, detailed quotes upfront, so you know exactly what to expect without any hidden surprises. We'll help you understand where your money goes and how to get the best value for your investment.
Planning Permission and Building Regulations
Do you need planning permission for a garage conversion? Often, garage conversions fall under 'permitted development,' meaning you might not need full planning permission. However, they always need to comply with building regulations. We'll guide you through every step, handling all necessary applications and ensuring your project meets all legal requirements for safety, insulation, and structural integrity.
Garage Conversion vs. Extension: What's Right for You?
You're weighing up your options, aren't you? A garage conversion typically offers a more cost-effective and quicker solution than a full home extension, as it utilises an existing structure. It's ideal if you need extra internal space without sacrificing garden area. We can discuss the pros and cons of each for your specific property and help you decide the best path forward.
Garage Conversion FAQs
Ready to Transform Your Garage?
Book a free site survey today. We'll assess your garage, advise on the best approach, and provide a detailed fixed-price quotation.
Where We Deliver Garage Conversions
TCM Building & Maintenance is based in Borehamwood and serves Hertfordshire, North London, and the surrounding area. Each location page covers planning authority details, property types, and local considerations specific to that area.
Our home base. Fast response times across the whole town.
Serving Radlett's conservation areas and Green Belt properties.
Covering Bushey, Bushey Heath, and the surrounding Hertsmere area.
Serving Potters Bar, Brookmans Park, Northaw, and Cuffley.
Full coverage across Watford and the Three Rivers district.
Experienced in St Albans conservation areas and listed buildings.
Covering Hatfield, Welham Green, Birchwood, and Old Hatfield.
Specialists in the WGC Conservation Area's Arts and Crafts properties.
Serving all parts of the London Borough of Barnet.
Covering Edgware, Canons Park, Burnt Oak, and Queensbury.
Serving Stanmore, Harrow Weald, Belmont, and the surrounding area.
Not sure if we cover your area? Call 07305 121634 — we serve a wide area across Hertfordshire and North London.