Insulation Below Suspended Timber Floors – Design Guidance

The Radon protection installed underneath the concrete cap on the air gap under a floor needs to spread through all of the building’s footprint.

Ballytherm Insulation needs to be packed inside the wall’s surface and the floor joists running parallel to it, to insure that the perimeter of the floor has been reached and insulated.

The design should eliminate as many holes and gaps as possible. For services, Ballytherm boards should be fitted specifically to allow for the item that the hole is prepared to accept, i.e. a specific cable or pipe. The remaining gap around the cable or pipe should be sealed shut. A different technical approach that can be used that would place the Ballytherm boards under the joists, forming a network of service holes or voids and minimise void areas.

a. radon barrier (if required)  b. Ballytherm Insulation packed between inner surface of wall and joist

Floor Insulation