A loft conversion is the most cost-effective way to add a bedroom and bathroom to your home without sacrificing garden space. RCB Design & Build has delivered hundreds of conversions across Greater London, Kent, Surrey, and Essex. We handle the full build as principal contractor — structural steel, floor strengthening, dormers, staircases, insulation, electrics, plumbing, plastering, and building control. Second-fix materials are client-supplied so you choose your own tiles, flooring, and sanitaryware.
A box-shaped dormer extends from the rear roof slope, creating full standing headroom and maximum usable floor area. The most popular conversion type in London.
The sloped hip end of the roof is rebuilt as a vertical gable wall, dramatically increasing internal volume. Common on semi-detached and detached houses.
The rear roof slope is rebuilt at a near-vertical angle (72°) with a flat top, creating the maximum possible floor area. Usually requires planning permission.
The simplest conversion — roof windows are installed into the existing roof slope with no external structural changes. Ideal when headroom is already sufficient.
Two dormers join at a right angle over the rear and side of the roof, creating enough space for two rooms plus a bathroom. Popular on Victorian terraces.
Most dormer and Velux conversions fall under permitted development and do not require a planning application. Mansard conversions and properties in conservation areas typically need full planning permission. We check your specific situation during the free site visit.
A standard dormer loft conversion takes 6–8 weeks on site. Hip-to-gable and mansard conversions can take 8–10 weeks. The staircase is usually installed in week 2, and the dormer is weathertight within the first 10 days.
As a rule of thumb, you need a minimum of 2.2m head height from the top of the ceiling joists to the ridge. We carry out a full feasibility check during the free site visit, including measurements and a structural assessment.
A loft conversion typically adds 20–25% to the value of a property. In London and the South East, this often means £60,000–£150,000 of added value, making it one of the highest-return home improvements available.
Yes. We design and install the staircase as part of the conversion. We work with you on positioning to minimise the impact on the floor below, and all staircases comply with Building Regulations.
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