EPDM restoration
Black rubber that has gone chalky and loose at the seams still has decades of membrane in it. Prime it, seal the laps and turn it white.
- Pr325Wash primer, one step under silicone or acrylic
- WhiteFinish over black rubber
What happens to EPDM
EPDM oxidizes and chalks from the surface down, and the seams go first: adhesive and tape laps lose their bond while the field sheet stays flexible. Ballasted roofs hide the same problems under stone, and a ballasted roof can't be coated.
Adhesion is the whole job. Silicone and acrylic will not bond to a chalky, unprimed sheet, so every EPDM system starts with a Pr325 wash primer, under silicone and acrylic alike: one step, not a wash and then a separate primer. Once it is primed, the rubber takes a coating as well as any substrate on this page.
A coating job when
- Seam tape or adhesive laps that can be re-stripped
- Fully adhered or fastened, not ballasted
- Tenting repaired first
- Wet areas repaired, or vented if under 500 ft²
- Owner wants a white, reflective roof
Not a coating job when
- The roof is ballasted
Not sure? Send photos and a core cut. A rep will call it.
The build-up, in order.
The default for EPDM: one wash primer, one mastic, one topcoat, and it tolerates the ponding water rubber roofs are known for.Where drainage is positive and the owner wants the reflectivity gain at the lowest cost per square.
Wash primer
Re-strip loose seams with tape, then wash-prime the whole field with Pr325 and rinse it clean: one step, not a wash and then a separate primer. Pull-test a 2 × 2 ft patch before you order.
Pr325 Alkaline Roof Cleaner1 gal / 500 ft²Seams & details
Mastic over every lap, curb, drain and penetration. Fabric at open seams and splits.
Si790 Silicone Mastic1 gal / 60 lin ftWalkways
Around units and along service paths, set into wet topcoat and clipped at the corners.
GripTite Walkway Pad Walkway ProtectionSized to layout
Wash primer
Re-strip loose seams with tape, then wash-prime the whole field with Pr325 and rinse it clean: one step, not a wash and then a separate primer. Pull-test a 2 × 2 ft patch before you order.
Pr325 Alkaline Roof Cleaner1 gal / 500 ft²Seams & details
Fibered mastic at laps and details. Fabric at splits.
Ac595 Acrylic Mastic1 gal / 40 lin ftTopcoat
Second full coat at right angles to the first.
Ac550 Acrylic Roof Coating8.5 dry mils per gal / 100 ft²Walkways
Around units and along service paths, set into wet topcoat and clipped at the corners.
GripTite Walkway Pad Walkway ProtectionSized to layout
- 03 · TopcoatSi710
- 02 · Seams & detailsSi790
- 01 · Wash primerPr325
- Substrate · Aged EPDM membrane
Thickness not to scale. Optional steps appear here when switched on in the estimator below.
Rough quantities for this roof.
Enter the roof and get gallons and containers for the route above. It is a planning number, not a bill of materials — your rep confirms coverage before anything ships.
Estimate
25,000 ft² · 30 dry mils · silicone- 01Pr325 Alkaline Roof CleanerWash primer · 1 gal / 500 ft²56 gal12 × 5-gal pails
- 02Si790 Silicone MasticSeams & details · 2,500 lin ft · 10 penetrations49 gal25 × 2-gal pails
- 03Si710 Silicone Roof CoatingTopcoat · 30 dry mils750 gal13 × 55-gal drums + 7 × 5-gal pails
- 04GripTite Walkway Pad Walkway ProtectionWalkways · Rolls and clipsSized to the layout — your rep quotes it
Liquid product, all steps855 gal
- Smooth surface: no texture allowance
- 10% overage on every liquid product
- Quantities rounded up to whole gallons, then to full containers
- Pr325 at 1 gal / 500 ft² — SESCO EPDM guide specification
- Si790 at 1 gal / 60 lin ft of seam, 0.2 gal per penetration — rule of thumb
- Si710: 11 dry mils per gal / 100 ft² — TDS; 30 mils this coat
Rough estimate for planning. Actual coverage depends on surface porosity, texture, application method and verified mil thickness. Confirm with the TDS and your rep before ordering.
Estimate
25,000 ft² · 32 dry mils · acrylic- 01Pr325 Alkaline Roof CleanerWash primer · 1 gal / 500 ft²56 gal12 × 5-gal pails
- 02Ac595 Acrylic MasticSeams & details · 2,500 lin ft · 10 penetrations73 gal15 × 5-gal pails
- 03Ac510 Acrylic Roof CoatingBase coat · 16 dry mils500 gal9 × 55-gal drums + 1 × 5-gal pail
- 04Ac550 Acrylic Roof CoatingTopcoat · 16 dry mils518 gal9 × 55-gal drums + 5 × 5-gal pails
- 05GripTite Walkway Pad Walkway ProtectionWalkways · Rolls and clipsSized to the layout — your rep quotes it
Liquid product, all steps1,147 gal
- Smooth surface: no texture allowance
- 10% overage on every liquid product
- Quantities rounded up to whole gallons, then to full containers
- Pr325 at 1 gal / 500 ft² — SESCO EPDM guide specification
- Ac595 at 1 gal / 40 lin ft of seam, 0.3 gal per penetration — rule of thumb
- Ac510: 8.8 dry mils per gal / 100 ft² — SESCO build-up rate (the TDS states 9); 16 mils this coat
- Ac550: 8.5 dry mils per gal / 100 ft² — from 53% volume solids (the TDS states no dry-mil yield); 16 mils this coat
Rough estimate for planning. Actual coverage depends on surface porosity, texture, application method and verified mil thickness. Confirm with the TDS and your rep before ordering.
Case studies.
Case studies are on the way.
The data sheets for this route.
Published TDS and SDS for the silicone route. Ask your rep for any sheet not listed; the spec letter comes from your rep.Published TDS and SDS for the acrylic route. Ask your rep for any sheet not listed; the spec letter comes from your rep.
Order through your rep.
Reps confirm coverage and write the spec letter. Send the estimate, or call 1-812-776-6727.