When we complete a 6 Star energy rating assessment for our clients at Energy Rating Perth, our energy assessors go further and give recommendations on the building envelope and what materials will help improve thermal performance to our energy consumption conscious client.
The floor is a part of the building envelope and different floor types and renderings have an impact on the building’s thermal performance. If the floor is laid on the earth like a concrete slab, it acts as a thermal mass. A crucial factor is the covering on the concrete floor. If you glue a carpet onto the floor, it will insulate it and eventually no heat will be lost or gained by the thermal envelope. On the other hand, tiles or a polished render will allow the heat exchange to occur. A layer of insulation may be added between the slab and the earth so the heat is not lost back to the ground when the interior is of a cooler temperature (at night time in winters). Insulation might even be incorporated into the floor in a special concrete floor construction known as wafflepod slab. This slab consists of square blocks of polystyrene insulation placed with gaps in between. The concrete is poured over a reinforcement mesh and fills the gap between the polystyrene blocks to make a grid which strengthens as well as creates thermal bridging. Unlike conventional slabs, the wafflepod slab can provide thermal resistance up to R1.0 value. Another common floor type that the energy assessors at Energy Rating Perth recommend is a suspended timber floor. This consists of bearers and joists with a timber sheeting on top and usually some sort of bulk insulation underneath the raised floor. The advantage of this type of floor is that it allows air circulation in the floor space that brings the cooling effect into the interior space. At Energy Rating Perth, we recommended such floor types for hot climates and humid climates as it avoids heat gains from the ground and allows ventilation under the floor space.