Step 1: Pre-Coating Inspection and Moisture Survey
- Visual walk: document seams, penetrations, drains, flashings, and ponding zones with date stamped photos.
- Infrared scan: performed after sunset on a dry day to locate wet insulation. Any zone above 15% moisture content is cut out and replaced, not coated over.
- Core samples: minimum two per 10,000 sq ft, taken through the membrane to the deck to verify insulation condition.
- Adhesion test: a 2 ft by 2 ft trial patch of the proposed coating, pulled at 24 and 72 hours to confirm bond strength above 2.0 psi.
- Report: written findings with square footage of repair work, estimated coating gallons, and a go or no go recommendation.
A proper inspection takes 2 to 4 hours per 20,000 sq ft. We pair this with our commercial roof inspection protocol to document baseline condition before any product touches the membrane.
Step 2: Substrate Preparation
- Power wash: 3,000 psi minimum, hot water preferred, with a roof safe detergent. Rinse until runoff is clear.
- Dry time: 24 to 48 hours depending on humidity. Moisture meter must read below 5% before primer.
- Seam reinforcement: all field seams, penetrations, and flashings receive polyester fabric embedded in base coat at 1.5 gallons per square.
- Repairs: blisters cut and patched, fasteners reset, drains reflashed. Budget 5 to 15% of total job hours here.
- Primer: applied at the rate specified for your membrane type, typically 0.5 to 1.0 gallon per 100 sq ft.
Membrane-Specific Prep Notes
- EPDM: requires a dedicated EPDM primer or wash coat to break the surface oils. Skipping this step causes delamination within 6 to 12 months.
- TPO and PVC: oxidized surface layer must be removed by abrasion or chemical etch. Test a 4 ft by 4 ft area for adhesion before scaling up.
- Modified bitumen: granule loss above 30% needs a granule filling base coat at 2.0 gallons per 100 sq ft before standard application.
- Metal: rust spots wire brushed to bare metal, treated with rust converter, and primed with a corrosion inhibiting primer. Fastener heads receive a butyl cap or seam tape.
Step 8: Post-Application Quality Control
- 72 hour walk: inspect for pinholes, fisheyes, holidays, and uncured zones. Touch up with brush applied material.
- Flood test: on low slope sections with internal drains, plug drains and flood to 2 inches for 24 hours where structurally permitted.
- Photo log: overhead and detail shots of every penetration, seam, and transition delivered to the owner as a closeout package.
- Maintenance plan: debris removal twice per year, drain clearing each spring and fall, and a written log kept on site.
- Owner handoff: Brownstown Commercial Roofing provides system data sheets, warranty registration, and a recoat reminder tied to year 8 or year 10 depending on chemistry.
If you want a project specific scope and number for your building in Brownstown, contact Brownstown Commercial Roofing for a site visit. Severity is assessed over the phone, inspections are scheduled fast, and active leaks are prioritized for tarping and dry in before the coating scope is finalized.
Step 6: Decision Criteria, Coat or Replace
- Wet insulation below 25% of roof area: coating is viable after cut outs.
- Wet insulation above 25%: recommend tear off. Review our coat vs replace decision guide.
- Membrane age under 20 years and seams intact: coat.
- Active leaks at multiple penetrations: repair first, then coat, or move to replacement.
- Deck rust or rot: coating will not save it. Replace.
Step 4: Application Specifications
- Base coat: applied at 1.0 to 1.5 gallons per 100 sq ft. Wet mil gauge readings every 500 sq ft.
- Cure window: 8 to 24 hours before top coat depending on chemistry and temperature.
- Top coat: applied perpendicular to base coat direction for full coverage. Same gallon rate.
- Final dry mil verification: destructive sample pulled, measured with micrometer at 5 locations per 10,000 sq ft. Must hit spec or a third coat goes on.
- Weather hold: no application below 50°F, above 90°F, or with rain forecast inside 24 hours.
Equipment and Crew Sizing
- Airless sprayer: minimum 1.5 gpm output, 3,300 psi rating, with 0.035 to 0.045 reversible tips for silicone and polyurethane.
- Roller backup: 3/4 inch nap covers for cut in around curbs, drains, and parapet walls.
- Mil gauges: wet film gauge in every applicator's pocket, dry film micrometer at the foreman's station.
- Crew ratio: one sprayer, two back rollers, one mixer and supply runner for every 8,000 to 10,000 sq ft per day.
- Safety: fall protection anchored per OSHA 1926.502, respirators for solvent based systems, and edge warning lines 6 ft from the roof perimeter.
Step 3: Coating System Selection
Chemistry drives both cost and performance. The four common systems in Brownstown:
- Silicone: best for ponding water. 25 to 30 dry mils. Lifespan 15 to 20 years. Does not chalk in UV.
- Acrylic: lowest cost, best reflectivity. 20 to 25 dry mils. Lifespan 10 to 15 years. Avoid on ponding roofs.
- Polyurethane: highest tensile and abrasion resistance. 20 dry mils. Lifespan 15 to 20 years. Used on high traffic roofs.
- SPF (spray polyurethane foam) plus topcoat: adds R-value. 1.5 inches foam plus 20 mils silicone. Lifespan 20 years with recoat.
For a head to head breakdown, see our comparison of silicone vs acrylic roof coating.
Step 5: Cost Breakdown by System
Line Items That Move the Number
- Repair scope: wet insulation cut outs run $4.50 to $8.00 per sq ft of replacement area.
- Primer requirement: EPDM and aged TPO add $0.20 to $0.45 per sq ft.
- Access: crane or boom lift for material staging adds $1,500 to $4,500 per mobilization.
- Roof complexity: heavy penetration density (HVAC, skylights, vents) can add 15 to 25% labor.
- Tax credit eligibility: reflective systems meeting CRRC standards may qualify for Section 179D deductions on commercial properties.
Step 7: Warranty and Recoat Schedule
- Manufacturer material warranties run 10, 15, or 20 years tied to mil thickness applied.
- Annual inspection required to maintain warranty validity.
- Recoat at 50 to 60% of original system age extends life by another full warranty cycle.
- Document every recoat with dry mil verification and photos.