By Sam Hostetler, owner of Revive Commercial Roofing, in commercial roofing since 2009.
The short answer
If your roof deck is sound and most of the existing roof is dry and still attached, a restoration coating can usually seal it and extend its life for less money and disruption than a tear-off. If the roof has widespread wet insulation, a damaged deck, or a membrane that's falling apart, you're usually better off with replacement, such as a new TPO or PVC membrane. The only way to know which camp your roof is in is a careful inspection.
When a roof coating makes sense
- The roof is aging, chalky, or weathered, but still attached to the building.
- Leaks are limited to specific spots, usually seams, flashing, fasteners, or penetrations.
- The insulation under the roof is mostly dry. Small wet areas can be cut out and replaced.
- The roof deck and structure are sound.
- You want to keep the building open while the work happens.
- You'd rather not pay to tear off and haul away a roof that still has life in it.
When replacement makes more sense
- Moisture is trapped across large parts of the roof.
- The deck is rusted through, rotted, or sagging.
- The membrane is shrinking, splitting, or detached across the roof.
- The roof has already been covered over as many times as code allows.
- You're changing the building's use, insulation, or layout in a way that calls for a new roof system.
Side-by-side comparison
How the inspection decides it
A good roof inspection answers three questions: Is the roof dry underneath? Is it still attached and sound? Where is the water getting in? To answer them, we walk the whole roof and check the surface, seams, flashing, drains, and penetrations, and look for the signs of trapped moisture such as soft spots and blistering. Then we tell you plainly which option fits your roof, including when a coating is not the right call. Your first roof inspection is free.
What drives the cost either way
- Roof size and access. Larger roofs cost more overall, but often less per square foot.
- Repairs needed first. Seams, flashing, fasteners, drains, and any wet areas that must be replaced.
- Tear-off and disposal. A big part of many replacement budgets, and usually avoided with restoration.
- Rooftop equipment and details. Units, curbs, skylights, and penetrations take time to detail properly.
- The system you choose. Different coatings and membranes have different material and labor costs.
We don't publish prices because every roof is different, but we'll walk you through the numbers for your building.
Which coating, if you coat?
Silicone roof coatings are common on flat and low-slope roofs. Acrylic roof coatings are common on metal and sloped roofs. Spray-foam roofs, aging single-ply membranes, and metal roofs each need their own prep. Learn more on our commercial roof coating and metal roof restoration pages.
Timing in Montana
Coatings need dry weather and temperatures within the manufacturer's limits, so most coating projects in Montana are scheduled in the warmer, drier months. Inspections and repairs can often happen earlier. If you're thinking about a coating this summer, an inspection in spring gives you time to plan and budget.
Questions to ask any roofing contractor
- Is my roof dry underneath, and how do you know?
- What repairs are included before the coating or new roof goes on?
- Which coating or membrane do you recommend, and why that one for my roof?
- Who makes the system, and are you approved to install it?
- What warranty is offered, by whom, and what maintenance does it require?
- Can my building stay open during the work?
