Which is better for insulating a basement wall?

The FOAMULAR 150. Its R-5 per inch and 15 psi strength suit foundation and cavity walls, and it costs far less per square foot.

Is the Insul-EZ worth $267.50?

Only for small adhesive jobs like wrapping ducts or equipment. For area coverage, the FOAMULAR board at $33.35 for 32 sq ft is much cheaper.

Which has a higher R-value?

FOAMULAR 150 at R-5 per inch. The Insul-EZ sheet is R-3.0 at 3/4 in, which is about R-4 per inch.

Can I use either one outdoors or in wet areas?

FOAMULAR 150 is closed-cell XPS with 0.10 water absorption, so it handles damp foundations and crawl spaces. The Insul-EZ sheet is thin foam with an adhesive backing, better suited to dry, protected spots.

Which is easier to install?

The Insul-EZ peels and sticks with no fasteners. The FOAMULAR board is rigid and needs adhesive or cap fasteners, but it cuts and scores easily.

Does either come in other thicknesses?

FOAMULAR 150 comes in 1, 1.5, 2, 2.5 and 3 in. The Insul-EZ sheet is 3/4 in only.

Insul-EZ 4x4 Foam Insulation Sheet vs Owens Corning FOAMULAR 150 XPS Board

For most insulation jobs, buy the Owens Corning FOAMULAR 150. It gives R-5 per inch, comes in 4 ft x 8 ft boards, and costs $33.35 at Home Depot as of November 7, 2026. The Insul-EZ sheet is a thin 3/4 in peel-and-stick foam at R-3.0, priced at $267.50 as of November 4, 2026, so it only makes sense for small adhesive-backed jobs like duct or equipment wrapping.

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