The walls on which any new wall or floor resides must be load bearing. Load bearing means to have the capacity to carry the new weight eventually leading to a concrete or stone foundation. This aspect is critical to ensure local authority approval.

In all dwellings other than existing bungalows the new room must be separated from the rest of the house by a half hour fire resistant partition and self-closing fire door. The fire door to the new room may be positioned at the top or the bottom of the new stairway.

The existing walls around the existing stairs should have a minimum of half hour fire resistance.

Glazing in any existing walls or doors around the stairwell must be eliminated or replaced with fire retardant glass.

The new dormer walls must be treated with a weather resistant finish and provided with thermal insulation. If a wall to a dormer is within 1m of the boundary to a neighbouring property it will be necessary to provide fire protection to the wall from the inside and outside.

Acoustic insulation blanket installed in all internal dividing partitions.