This is the simplest and cheapest attic conversion, and excellent for a bigger loft with sufficient height. It is achieved completely within the existing roof space, and does not require building permission. Particularly suitable for a listed property or areas of London, as it doesn’t affect the external appearance or structure of the building.

Dormer conversions generate more usable space than Velux conversions, often allowing for creation of at least two additional rooms/bathrooms. A dormer or dormers project from the roof surface and thus creates extra standing room. More complex dormer conversions (such as full-width dormer or an L-shaped dormer) are particularly effective at creating extra full headroom). Simpler dormer conversions might not need planning permission.

The roof is extended as the hip end is replaced with a gable end. This maximises the usable space in the loft and head height.  As a hip-to-gable conversion entails external alterations, planning permission will be needed.

Mansard conversions entail more substantial alterations than other loft  conversions, but extend the loft along the full length of the roof. The slope is replaced with an nearly-vertical wall with a nearly-flat or flat roof. Because of the extent of structural alterations, mansard conversions are usually the most costly and will nearly always require planning permission, but the potential gain in headroom and floor area is also the greatest.