Floor insulation

Ground floors can be a significant source of heat loss, however it is important to determine what type of floor you have before carrying out any works.

Suspended timber ground floors are particularly draughty and thermally inefficient. You can insulate below or above the boards and install a floor finish to help seal the gap between boards and at the edges. Suspended floors stay dry because they are separated from the ground by a void ventilated with external air. It is essential to maintain ventilation to any floor void to prevent damp and rot. Alternatively you can replace a suspended timber floor with solid floor construction, such as concrete, adding significant levels of insulation. However, concrete has a high carbon footprint and changing the floor to an impermeable material such as this can also impact the damp levels in your walls. You should seek professional advice from a Chartered Surveyor or Architect, who can suggest alternative ‘breathable’ material’s such as lime-crete.
If your property has an existing solid floor it is likely to be concrete. If it was installed more than

20 years ago it is unlikely to be insulated. You may also have uninsulated heating pipes within the floor slab. Removing existing concrete floors to add insulation is a significant building project and you should seek professional advice from an experienced builder, Surveyor or Architect.

What is a U Value?
A U-value is a measure of how quickly heat passes through walls, windows, floors or roofs. The lower the numeric value the better the thermal performance of the building element.

Building regulations Part L1(a) Limiting (maximum) U values for new fabric elements in existing dwellings
  • ROOF


  • WALL