Passive House Foundations

This F-element insulated foundation system developed in 2004/05 delivers one of the best U-values (0.107) on the market by eliminating the Cold Bridge between the wall and the floor. Our foundations are built using structural Polystyrene (EPS) engineered to take loads of up to 120kN/m, making it an excellent choice for any type of structure in built Passive Houses. EPS 300 can take loads of up to 120kN/m2 which is about 12 tonne/m2.

The house sits on a reinforced insulated ring beam with an insulation upstand dividing the ring beam and the concrete floor.

Swedish tests show that 65% of the heat from UF heating is lost to the ground when a standard Irish foundation system is used, our system reduces the heatloss to 17%. This Swedish L-element foundation system (below) developed in the early 90's is still commonly used in Sweden and offers a U-value of 0.178 when 300mm of EPS is used under the floor. But as you can see above the F-element delivers a much better U-value.

The upside-down T element is used for heavier loads and can take loads up to 350kn/m (35 tonnes/linear metre). Heavy internal loads can be easily taken by thickening the slab and putting EPS 300 under the floor at this point.