L-Shaped Loft Conversion London and Hertfordshire
The ultimate loft conversion for Victorian and Edwardian terraced houses with rear outriggers. An L-shaped loft conversion adds two dormers — one on the main roof and one on the outrigger — creating the maximum possible loft space. LCCL Construction designs and builds L-shaped lofts across London and Hertfordshire. Full design and build from £40,000. LABC Award Winners 2024. Over 200 reviews rated 4.7 out of 5.
LABC Awards
Winners 2024
200+ Reviews
4.7 / 5 Rating
NFB Members
LABC Partners
What Is an L-Shaped Loft Conversion?
An L-shaped loft conversion is designed specifically for properties with a rear outrigger — the section of the house that extends beyond the main rear wall at a lower level. By adding a dormer to both the main roof and the outrigger roof, the conversion creates an L-shaped floor plan that maximises the total loft space.
L-shaped conversions are the most popular loft type for Victorian and Edwardian terraced houses across London, where rear outriggers are a common architectural feature. The L-shape typically creates enough space for two bedrooms and a bathroom, or a large master suite with walk-in wardrobe and en-suite.
The design requires careful architectural planning to connect the two levels where the main roof and outrigger roof meet. This junction is one of the most technically challenging aspects of loft conversion design, which is why choosing an experienced company is essential.
LCCL Construction has extensive experience designing and building L-shaped loft conversions across London and Hertfordshire. Based in Finchley, London N3, with over 20 years of experience, 200+ reviews rated 4.7/5 and LABC Awards Regional Winners 2024.
How Much Does an L-Shaped Loft Conversion Cost?
L-shaped loft conversion costs in London typically range from £40,000 to £65,000 depending on the size of the property, the depth of the outrigger and the specification:
Standard L-shaped (2 bed + bathroom): £40,000 to £50,000.
Large L-shaped (master suite + second bedroom): £50,000 to £58,000.
Premium L-shaped (high specification finishing): £55,000 to £65,000.
Prices include full design and build. Get an instant quote at lcclconstruction.co.uk or call 020 8037 7332.
Subject final drawings, how big the area is, location, finishing, structural drawings, alteration, time when, costs subject to change.
Planning Permission
Most L-shaped loft conversions fall under permitted development rights on terraced houses, provided the volume does not exceed 40 cubic metres. The dormer must not extend higher than the existing roof ridge and must be set back from the eaves.
Planning permission is required in conservation areas and for listed buildings. LCCL Construction handles all applications.
What Is Included?
Full design and build: consultation, measured survey, architectural design, planning, building regulations, structural calculations, party walls, all construction including both dormers and the junction between them, staircase, electrics, plumbing, plastering, decoration, building control sign-off and optional 10-year LABC warranty.
Areas We Cover
We design and build L-shaped loft conversions across London and Hertfordshire including Barnet, Finchley, Hendon, Muswell Hill, Highgate, Hampstead, Crouch End, Stoke Newington, Hackney, Islington, Camden, Clapham, Putney, Wandsworth, Ealing, Southgate, Enfield, Edgware, Borehamwood and surrounding areas. Call 020 8037 7332.
Frequently Asked Questions
How much does an L-shaped loft conversion cost?
L-shaped loft conversions in London cost £40,000 to £65,000 for full design and build. A standard L-shaped with two bedrooms and bathroom typically costs £40,000 to £50,000.
Which houses suit an L-shaped loft conversion?
Victorian and Edwardian terraced houses with rear outriggers are ideal. This is the most common property type across inner London boroughs.
How much space does an L-shaped loft create?
An L-shaped loft typically creates 25 to 40 square metres of usable floor space — enough for two bedrooms and a bathroom, or a large master suite with en-suite and walk-in wardrobe.
Is an L-shaped loft conversion worth it?
Yes. An L-shaped conversion creates the most space of any loft type on a terraced house and typically adds 15% to 25% to property value. On a £500,000 London home, that is £75,000 to £125,000.
How long does an L-shaped loft conversion take?
An L-shaped loft typically takes 10 to 14 weeks to build. The full timeline is 5 to 7 months from consultation to completion.
How do I get started?
Call 020 8037 7332, book a free consultation at lcclconstruction.co.uk, or get an instant quote online.