Energy Efficient Housing Research Group

EEHR

Insulating Under the Slab

The construction crew completed installation of the underslab insulation today. This insulation, 2 inches of extruded polystyrene (XPS), will keep heat from escaping the concrete floor slab into the ground, and it will help to keep the concrete slab dry. Below the insulation is a layer of crushed stone to ensure that all water is able to drain away from the slab, keeping it dry and free of cracks. Before Envinity pours the concrete slab, they will lay down overlapping sheets of 6 mil polyethylene as a final layer to protect the concrete slab from water and moisture. All of this protection will make the slab warmer but will also keep it lasting for decades without issues of cracking or breaking.

Insulating the Foundation

Today, members from Envinity’s construction team were insulating the foundation of the GreenBuild homes. It’s often overlooked, but heat is able to escape the home through the foundation, in some cases, enough to actually melt snow surrounding the home! The GreenBuild homes are being built with 2″ of Extruded Polystyrene (XPS) rigid insulation to the inside of the foundation walls and under the first floor concrete slab; XPS insulation in a high-density foam insulation able to withstand the constant pressure of the floor slab and hydrophobic so that no water will enter the insulation, keeping it performing well throughout the lifespan of the homes. This insulation will reduce thermal bridging and help to keep the interior of the homes warm throughout the harsh Central Pennsylvania winters.

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