5 Things to Know About Re-Roofing a Commercial Building

Re-roofing a commercial building is one of the largest capital expenditures most building owners face. Here are 5 things you must know before making any decisions.

1. "Re-Roofing" Can Mean Different Things

Re-roofing can mean full tear-off and replacement, roof recovery (installing a new system over the existing one), or restoration with a coating system. These options have dramatically different costs, disruption levels, and performance outcomes. Don't assume "re-roofing" means replacement.

2. Core Samples Determine Your Options

The moisture level in your existing insulation is the single most important factor in determining what approach is viable. You cannot know this without core samples. Any contractor who quotes a system without doing core sampling is making assumptions — not recommendations.

3. The 25% Rule Is the Key Threshold

Less than 25% wet insulation: restoration is almost certainly viable. More than 25%: full replacement becomes more cost-effective. This threshold drives virtually every "restore vs. replace" decision.

4. Restoration Costs 50–70% Less

For qualifying roofs, silicone coating restoration at $2–$5/sq ft or spray foam at $4–$8/sq ft costs dramatically less than replacement at $7–$14/sq ft. This difference is worth investigating before committing to replacement.

5. Manufacturer Warranty vs. Contractor Warranty

Always insist on a manufacturer-backed warranty. Contractor warranties expire when the contractor goes out of business. Manufacturer warranties protect your investment regardless of who performs future work.