Loft Conversions in London

Flint Building Solutions is a trusted loft conversion specialist serving North and Central London. We transform unused roof spaces into beautiful, functional rooms — whether you need an extra bedroom, a home office, a bathroom or a playroom.

We manage the entire loft conversion process from initial survey and architectural drawings through to structural work, insulation, plastering, electrics, plumbing and final decoration. Our team has extensive experience with all types of loft conversions and works closely with local planning authorities to ensure full compliance.

Our loft conversion services include:
• Dormer loft conversions
• Hip-to-gable loft conversions
• L-shaped loft conversions
• Mansard loft conversions
• Velux and rooflight loft conversions
• Staircase design and installation

A loft conversion is one of the most cost-effective ways to add space and value to your home. Most projects are completed within 6 to 10 weeks, with minimal disruption as work is carried out from the outside in.

Contact us today for a free survey and no-obligation quote.

How much does a loft conversion cost?

Loft conversions start from £25,000. That is a Velux conversion — roof windows fitted into the existing roof line, with no dormer and no change to the shape of the roof.

The price rises with the type of conversion you need. A rear dormer adds a box structure at the back and gives full head height across the room — it is the most common choice in London. An L-shaped dormer runs over both the main house and the back addition, and is roughly double the work.

A mansard rebuilds the whole rear roof slope and is usually what planning requires in conservation areas and much of central London. An en-suite bathroom in the loft adds roughly £8,000 to £15,000 on top for the plumbing, sanitaryware and tiling.

Guide prices only, including VAT. What moves the figure: the type of conversion, the head height and structure of your existing roof, how far the new staircase has to travel, whether steels are needed, and the specification you choose inside. Outer north London boroughs sit at the lower end; central London and conservation areas sit considerably higher because of planning restrictions, mansard requirements and access costs.

How long does it take?

A Velux conversion takes 4 to 6 weeks on site. A standard rear dormer takes 6 to 10 weeks of building work, or 10 to 14 weeks from the crew arriving to final decoration and sign-off. An L-shaped dormer takes 12 to 16 weeks. A mansard takes 10 to 14 weeks.

Loft conversions — common questions

Do I need planning permission? Most rear dormers fall under permitted development. Mansards, front-facing dormers, flats, listed buildings and properties in conservation areas almost always need a planning application. We check this before quoting so you know which route you are on.

Is my loft tall enough? As a rule of thumb you need at least 2.2 metres from the existing floor to the ridge for a conversion to be worth doing. If you have less, a dormer or a mansard can create the height instead. We measure this at the first visit and tell you straight away if it does not work.

Where will the staircase go? This is usually the part that decides the layout. The new stairs normally rise over the existing staircase, which means losing a small amount of space on the floor below. We work this out at design stage, before you commit.

Can I stay in the house during the work? Yes, for most of it. The roof is opened up from the outside, and the loft is sealed off from the rest of the house. The noisiest stage is the steelwork and the opening of the ceiling for the stairs.

What areas do you cover? We are based in Waltham Cross and build loft conversions across north London and Hertfordshire — Enfield, Cheshunt, Barnet, Edmonton, Tottenham, Waltham Abbey and the surrounding areas — as well as central London.