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.
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.