Loft Conversions
London & Hertfordshire
Transform your unused loft space into a beautiful, functional room. TCM Building specialises in all types of loft conversion — from simple Velux installations to complex L-shaped dormers — across London and Hertfordshire.
Turn Wasted Roof Space
Into Living Space
A loft conversion is the process of converting an existing, unused loft or attic space into a habitable room — typically a bedroom, home office, bathroom, or playroom. It is one of the most cost-effective ways to add living space to your home because the roof structure already exists; you are simply making use of space that is currently going to waste.
For homeowners in London and Hertfordshire, where property prices are high and gardens are often small, a loft conversion is frequently the most sensible alternative to moving. It avoids the significant costs of stamp duty, estate agent fees, and conveyancing, while creating a home that is perfectly tailored to your needs.
TCM Building has completed over 150 loft conversions across London and Hertfordshire. Our team manages the entire process — from the initial loft survey and architectural drawings through to Building Regulations approval, structural engineering, and final decoration.
Which Type Is Right for Your Home?
Dormer Loft Conversion
A dormer loft conversion is the most popular type in London and Hertfordshire. It involves extending the existing roof vertically to create a box-shaped structure with a flat or pitched roof, adding significant headroom and floor area. A rear dormer can often be built under Permitted Development rights, making it the most straightforward option for most homeowners.
Key Suitability Checks
Most lofts in London and Hertfordshire are suitable for conversion. Here are the key factors we assess during the free loft survey.
Not sure if your loft qualifies?
Book a free loft survey and we'll assess your loft in person. Even if your loft doesn't meet all the criteria above, there may still be options — for example, a Velux conversion requires less headroom than a dormer.
From Survey to Handover
Free Loft Survey
We visit your property and carry out a full loft survey — measuring headroom, assessing the roof structure, and identifying any potential issues.
Design & Drawings
Our design team produces full architectural drawings showing the proposed layout, staircase position, and window locations.
Planning & Building Regs
We advise on Permitted Development vs. planning permission and submit all necessary applications. We also handle Building Regulations approval.
Structural Engineering
A structural engineer designs the steel beams, floor joists, and any necessary strengthening works.
Construction
Our team carries out all works — from temporary roof protection and structural steelwork through to plastering, electrics, and plumbing.
Finishing & Handover
We complete all second-fix works, install the staircase, and finish to your chosen specification before final handover.
Loft Conversion Cost Guide
All prices are indicative for London and Hertfordshire. A fixed-price quotation is provided after the free loft survey.
| Conversion Type | Typical Cost | Added Value | Build Time | Planning |
|---|---|---|---|---|
| Velux / Rooflight | £20,000 – £40,000 | 15–20% | 4–8 weeks | Usually PD |
| Rear Dormer | £35,000 – £60,000 | 20–25% | 8–12 weeks | Often PD |
| Hip-to-Gable | £42,000 – £70,000 | 20–25% | 10–14 weeks | Required |
| Mansard | £45,000 – £75,000 | 25–30% | 10–14 weeks | Required |
| L-Shaped Dormer | £50,000 – £90,000 | 25–35% | 12–16 weeks | Required |
PD = Permitted Development. All prices exclude VAT. Fixed-price quotation provided after free loft survey.
"We had a full L-shaped loft conversion done and couldn't be happier. From planning to completion, TCM managed everything seamlessly. The quality of workmanship is exceptional — we now have two beautiful bedrooms and a bathroom where there was nothing before."
Book Your Free Loft Survey
Our loft specialist will visit your property, assess suitability, and advise on the best conversion type for your home — completely free of charge.
Running out of space at home is a common headache, isn't it? Maybe your family's growing, or you just need that extra room for a home office, a guest bedroom, or even a quiet retreat. You're probably wondering how to make your home work better for you without the upheaval of an extension or moving house entirely. A loft conversion is simply transforming your unused attic into a functional, habitable room. We're talking about converting that dusty storage area into a bright, airy space that truly enhances your home. It's about smart design and clever construction, turning dead space into living space. Why does it matter? It's a fantastic way to add significant value to your property, often more cost-effectively than a traditional extension. Plus, you get to stay in the home and area you love, avoiding all the stress and expense of moving. It's about creating the space you need, right where you are.
Do you ever look up at your unused attic space and wonder what it could become? Perhaps you're feeling the squeeze in your home, dreaming of an extra bedroom, a dedicated workspace, or just more room to breathe. You know you need more space, but you're not sure how to achieve it without turning your life upside down.
What You Need to Know
Tailored Design & Planning
Every home is unique, and so is every loft conversion. We work closely with you to design a space that fits your lifestyle and budget, ensuring it complements your existing home. From initial concepts to detailed drawings, we'll guide you through the whole process.
Expert Craftsmanship & Build Quality
Our skilled team brings years of experience to every project, ensuring your loft conversion is built to the highest standards. We use quality materials and proven techniques to create a durable, beautiful, and safe new space for your family.
Seamless Project Management
We handle everything from start to finish, coordinating all trades and ensuring the project runs smoothly and on schedule. You'll have a dedicated project manager keeping you informed every step of the way, making the process stress-free for you.
Compliance & Regulations Handled
Navigating planning permission, Building Regulations, and the Party Wall Act can feel overwhelming. Don't worry, we've got it covered. Our team manages all the necessary paperwork and liaises with local authorities and structural engineers to ensure full compliance.
Everything Else You Should Know
Understanding Loft Conversion Costs
The cost of a loft conversion varies quite a bit depending on the type, size, and finishes you choose. Things like dormer, hip-to-gable, or mansard conversions each have different structural requirements and, therefore, different price points. We provide clear, detailed quotes upfront so you know exactly what to expect, with no hidden surprises.
Planning & Regulations: What You Need to Know
Most loft conversions fall under permitted development, meaning you might not need full planning permission. However, Building Regulations approval is always a must to ensure safety and structural integrity. We'll help you understand the specific requirements for your property and handle all the applications.
Loft Conversion vs. Moving House
When you're weighing up your options, a loft conversion often comes out on top compared to moving. You save on stamp duty, solicitor fees, and the general upheaval of relocating. Plus, you get to add significant value to your current home while staying in the neighbourhood you love.
Common Mistakes to Avoid
One big mistake is not properly assessing your roof structure early on; not all lofts are suitable for conversion without major work. Another is underestimating the importance of good insulation and natural light. We'll help you avoid these pitfalls, ensuring your conversion is both practical and comfortable.
Loft Conversion FAQs
Ready to Transform Your Loft?
Book a free loft survey today. We'll assess your loft, advise on the best conversion type, and provide a detailed fixed-price quotation.
Where We Deliver Loft 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.