How to renovate a top-floor ceiling

The top-floor ceiling is a building element which can be insulated easily and with great effect. Insulation is installed above the ceiling, if possible.

Insulation below the ceiling is possible in principle, but involves a more elaborate design and greater cost, and is more difficult in terms of the physics of buildings, because it then corresponds to interior insulation and presents the same problems.

Screed over the insulation of a top-floor ceiling (source: Schulze Darup)

It makes a difference whether reinforced-concrete ceilings and timber beam ceilings are in place.

Reinforced-concrete ceilings: insulation is usually installed over the ceiling. Any loose-fill materials, blanket insulation and panels can be used.
Timber beam ceilings: basically the same applies here, but insulation can also be installed between the beams. However, one must check whether the additional expense is worthwhile. The structure must be made airtight, to avoid condensation in the insulation layer.

Insulation of a timber beam ceiling (source: Schulze Darup)