Ground Floor Insulation Guide - Insulation Applied Below Concrete Screed

Building Element - The Back Stops……… Ground Floor; Insulation below concrete screed

  • U value Target; Ground floor; no under floor heating                  0.18 W/m²K
  • U value Target; Ground floor; with under floor heating                0.15 W/m²K

NOTE: The back-stop U values in many cases will not be enough to satisfy the new NZEB targets. The preliminary BER; building energy rating calculation will identify the U value targets and also the performance required from associated building materials.This will include the airtightness level, the heating/ventilation system type and efficiency, the U values for the windows and the external doors and also thermal bridging measures.


Click here for Ground Floor; U value Calculations and Insulation Guides.


NOTE: If you are building your own home the U value target for the floor should not be higher than 0.15 W/m²K.

You only get one shot at insulating the ground floor. Don't listen to the question; what can I get away with.... Future Proof.


NOTE: If you are pouring concrete over foil faced insulation boards it is recommended that you overlay the insulation with a lightweight polythene prior to pouring the concrete. It's written in the manufacturers brochures and guidelines.

Food for thought: As we increase the airtightness of our homes we must pay more attention to the quality of the radon barrier we choose; the quality of the installation and ensure we protect the radon barrier at all times during construction. Radon gas is a killer.



Prevention is Cheaper than Cure....

For insulation advice call: Dermot Kearns Mobile: 087 0526909