Loft Conversions in Kent, Sussex and Surrey

Which conversion suits the roof

A rooflight conversion barely alters the roof and suits lofts that already have generous height along the ridge. A rear dormer replaces part of the falling slope with a vertical wall and flat ceiling, roughly doubling the area with full standing height.

Hipped roofs usually need the hip building up into a gable before a dormer is worthwhile, and houses with a rear outrigger can take an L shaped dormer, which is the largest option and typically yields two rooms plus a bathroom.

Head height and structure

Measure from the top of the existing ceiling joists to the underside of the ridge. Around 2.2m is the practical floor, because the new floor structure and the insulated ceiling build up together take 250mm to 350mm out of the raw figure.

Trussed rafter roofs, common from the mid 1960s onwards, need a designed structural frame installed before the trusses come out. That is identified at survey rather than discovered mid build.

Frequently asked questions

Do I need planning permission for a loft conversion?

Many rear dormers fall under permitted development on a house within the volume limits, provided the property is not listed, in a conservation area or covered by an Article 4 direction. Building regulations approval is always required.

How long does a loft conversion take?

Around four weeks for a rooflight conversion, five to six weeks for a rear dormer with an en suite, six to eight weeks for hip to gable with a dormer, and eight to ten weeks for an L shaped dormer.

What drives the cost?

The existing roof structure, the size of any dormer, the en suite drainage route, the staircase position and the finish specification.