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.
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.