We have been involved in a number of projects using insulated foundations. In general, these involve building the concrete foundations on structural polystyrene (EPS) that is strong enough to support the weight of the building. These types of foundations are best suited to lighter building types,such as Timber Frame and Poroton blockwork. However, we have also designed variations of these systems to facilitate more traditional constructions using blockwork and ICF.

Aeroground  (http://www.kingspaninsulation.ie/Products/Aerobord/Aeroground/Overview.aspx)

One of the two most common insulated foundation systems used in Ireland today is the Aeroground system. This system is manufactured by Aerobord Ireland to the specifications usually given by us. It provides precut forms for a reinforced concrete ringbeam around the perimeter of the building that are cut to suit each individual project, meaning they can then be assembled on site, like a jigsaw, to give a permanent formwork for the ringbeam that also insulated the foundation. Under the floor slab is usually insulated with 200mm – 300mm of standard polystyrene to provide passive levels of insulation. Where there are load-bearing internal walls, carrying some of the building weight, the floor slab is thickened locally and the polystyrene underneath the wall is upgraded to a structural grade to carry these loads. The floor slab is generally reinforced with steel and reduced to 100mm thick, and extra reinforcement is used under the load-bearing internal walls.

Kore Passive Slab  (https://www.kore-system.com/kore-products/floor-insulation/kore-passive-slab/what-is-kore-passive-slab)

Kore also provide insulated foundations, which they call passive slabs. These slabs/foundations can be made up using many different arrangements of insulation to suit the type of construction going on top of the slab. Internal walls are supported in the same way as with the Aeroground system. The thickness of insulation under the floor is again usually 200 – 300mm, but can be adjusted to suit the needs of each project.

Both of the above systems have been used successfully to achieve passive levels of insulation for house foundations. There are other insulated foundation systems on the market, such as Isoquick, but these are somewhat less thermally efficient at the external wall/foundation junction.

For photos of the above insulated foundations click here.