Suspended ground floors

5.2
Also See:
9.3
BRE report ‘Thermal insulation: avoiding risks’

5.2.9Thermal insulation and cold bridging

Suspended ground floors shall be insulated in accordance with building regulations to minimise thermal transmission through the floor and using materials suitable for the location and intended use.

Insulation should be installed to ensure that any risk of cold bridging is minimised, especially at junctions between floors and external walls. Cold bridging precautions include:

  • extending cavity wall insulation below floor level
  • providing perimeter insulation to floors.

Insulation below cast in-situ suspended ground floor slabs should be:

  • placed on a suitable, compacted and even substrate
  • of a material with low water absorption
  • resistant to ground contaminants
  • strong enough to support wet construction loads
  • compatible with any DPM.

Insulation for timber floors may be either insulation quilt or rigid insulation.

Cavity wall insulation should extend below the floor insulation level.

Insulation for use above suspended concrete floors should be in accordance with Chapter 9.3 ‘Floor finishes’.