How to Easily Raise Low Spots on a Commercial Roof?

Low spots on commercial roofs create ponding water — and ponding water accelerates membrane deterioration, increases leak risk, and can add structural load. Here's the easiest solution.

Why Low Spots Develop

Low spots typically form when insulation beneath the membrane becomes saturated with moisture and compresses over time. The resulting sag creates a depression that water pools in rather than draining toward outlets.

Traditional Approach: Labor-Intensive and Imprecise

With traditional roofing systems, raising low spots requires removing the existing membrane, cutting out and replacing compressed insulation with new material of varying thickness, then re-installing the membrane. This is labor-intensive, costly, and prone to imprecision.

The Spray Foam Approach: Simple and Effective

Spray foam is fluid-applied and can be feathered in at any thickness. After removing the wet insulation in the low area, foam is applied at greater thickness in the depression and tapered out to match the surrounding roof level — or to redirect drainage toward existing outlets. The process is fast, precise, and creates a seamless surface with no joints or transitions.

When It's Part of a Full Restoration

Slope correction is most cost-effective when combined with a full foam restoration. The entire roof gets a new seamless surface, drainage is optimized, and the building receives a new manufacturer's warranty — all in one project.