Insulating your basement floor provides added comfort and increased energy efficiency. When you insulate above your slab, the floor becomes noticeably warmer, making it a comfortable, more enjoyable living space that you can heat and cool for less.

Plasti-Fab’s code-listed EPS insulation is available in a variety of thicknesses to provide R-values to meet your desired energy efficiency. Insulating above a slab can be done during new construction or as a renovation project.

With the dependable distribution network of Plasti-Fab EPS insulation products and technical expertise readily available, insulating above a slab is a simple, cost-effective solution that provides long term benefits. The lightweight nature of EPS makes it easy to cut and install. Check out the Installation Instructions tab for a step by step guide to installing Plasti-Fab’s EPS insulation above your slab.

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Durofoam Insulating Under a Basement Slab

1. Follow the Building Code

Be sure to follow the building code requirements applicable in your region.

Durofoam Insulating Above a Basement Slab

2. Install a Moisture Barrier

Cover the entire floor area with a 6-mil polyethylene moisture barrier to eliminate moisture migration into your living area.

Durofoam Insulating Above a Basement Slab

3. Attach Perimeter Nailers

Attach nailer with the same thickness as the insulation, around the perimeter, using self-tapping concrete screws penetrating the concrete floor as recommended by the screw manufacturer.

Durofoam Insulating Above a Basement Slab

4. Install Nailers and Insulation

Cut the first row of insulation to a 21-3/4" width. Cut subsequent rows to 22-1/2" widths. Use the insulation cut as guides to place successive rows of nailers at 24" on centres. Install insulation with the green side facing up.

Durofoam Insulating Under a Basement Slab

5. Prepare to Lay Sub-Floor

Mark the walls where the nailer centres intersect it to help locate the nailers when attaching the sub-floor. The sub-floor thickness should be 5/8". Snap chalk lines across the nailers to ensure the sub floor material is placed squarely.

Durofoam Insulating Above a Basement Slab

6. Secure the Sub-Floor

Be sure to stagger the floor sheathing joints for extra stability. Apply adhesive to the nailers. Fasten the 5/8" floor sheathing directly to the nailers using either ringed nails or deck screws every 8". With an air nailer, use 2-inch ringed floor sheathing or screw nails. With a screw gun, use 1-1/2" or 1-3/4" deck screws.

Durofoam Insulating Above a Basement Slab

7. Ready for Floor Finishing

Your basement floor is now correctly insulated and ready for your final decorating touch. You should notice the finished floor is now much more comfortable.

Next Steps


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