Loft Insulation & Plastering

The finish that turns a structural shell into a comfortable, usable room

Once the structural shell of a loft conversion is complete, insulation and plastering are what actually turn it into a room that's comfortable to spend time in year-round, rather than a boarded-out space that's too cold in winter and too hot in summer.

A converted loft has more exposed roof area relative to its floor space than most rooms in the house, which means getting insulation right matters more here than almost anywhere else in the property. Insulation is fitted between and, typically, over the rafters to reduce heat loss through the roof slope, with particular attention paid to junctions — where a dormer meets the original roof, around rooflight windows, and at the eaves — since gaps at these points are where most heat loss and, in some cases, condensation problems actually occur, not in the flat expanses of insulated roof between them. Once insulation is in place, a vapour control layer is fitted before plasterboard goes up, which manages moisture movement through the roof structure and helps prevent condensation forming within the insulation itself over time. Plastering follows, finishing the boarded walls and ceilings to a smooth surface ready for decoration, with careful attention to the junctions between sloped ceiling sections and vertical dormer walls, which is where a less careful finish tends to show as visible lines or unevenness once the room is decorated and lit. Getting this stage right is what separates a loft conversion that's genuinely comfortable to use in January and July alike from one that technically meets the letter of building regulations but never quite feels like the rest of the house.