Suspended floor concession

Note. This help note applies only to certificates generated prior to 1 July 2017, or revision of those certificates if validly lodged with the consent authority.

BASIX gives a concession to dwellings that have little or no choice but to have a suspended floor due to site constraints, such as a sloping site, flood-prone area ormine subsidence area.

Suspended floors of any construction tend to have lower thermal performance than slab on ground floors. For both circumstances, BASIX increases the maximum heating and cooling loads.

Site slope > 10% below ground floor

The selected suspended floor has a site slope greater than 10% directly below all or part of that floor.

If a flat area is created under part of the floor for a garage or carport, the concession can still be claimed provided some part of the area under the floor has a greater than 10% slope.

You can select another floor type that is slab on ground or a suspended floor with flat ground below and still claim the concession for the suspended floor.

Your drawings MUST show the sloping site. It is good practice to show the calculated site slope to confirm that it is greater than 10%. As a minimum, the site slope must be able to be calculated by the consent authority.

Flood-prone area

The dwelling is required to have a suspended floor due to it being located in a flood-prone area.
Evidence to support the requirement for a suspended floor must be provided to the consent authority.

Mine subsidence area

The dwelling is required to have a suspended floor due to it being located in a mine subsidence area.
Evidence to support the requirement for a suspended floor must be provided to the consent authority.

Suspended floor concession - sloping site with calculated site slope greater than 10%Suspended floor concession - sloping site with calculated site slope greater than 10%