Pick the kit by matching it to your roof material: EPDM, fiberglass, and metal roofs each take different prep, primers, and coverage rates, so the roof itself decides the kit.
A coating kit that fails usually fails because it went on the wrong roof. Coating a fiberglass cap with an EPDM system, or skipping the primer a manufacturer requires, can leave you with peeling film by the next season. The fix costs nothing extra: read your roof material first, then buy the kit built for it. Dicor sells separate official systems for EPDM, fiberglass, and metal, and each one carries its own prep steps and coverage numbers.
Which Roof Material Do You Actually Have?
Most RV roofs fall into one of three materials, and the coating systems are not interchangeable. EPDM is the black or gray rubber membrane common on older travel trailers. Fiberglass is the smooth, hard shell found on many motorhomes. Metal roofs, usually aluminum, show up on older units and some toy haulers.
Look at the surface before you buy anything. Rub the roof with a clean white cloth: chalky gray residue and a slightly rubbery feel point to EPDM. A hard, glossy surface that sounds like plastic when tapped is fiberglass. Bare metal is obvious once it is clean — dull sheen, visible seams, sometimes surface rust.
- EPDM rubber: needs an EPDM primer and a kit built for rubber membranes, like Dicor’s RP-RRK-30 Rubber Roof Coating Kit, sized as a complete renewal system for a 30-foot unit.
- Fiberglass: needs a clean-and-prep product, light abrasion, and a fiberglass-specific coating. Dicor’s Fiberglass RV Roof Coating page lists RP-FRC-1 as a 1-gallon white coating.
- Metal or aluminum: needs rust removed down to bright metal, a rust inhibitor primer, and a metal-specific coating. Dicor’s Elastomeric Metal RV Roof Coating lists RP-MRC-1 in 1-gallon and RP-MRRIP-Q rust inhibitor primer in 1-quart sizes.
“Universal” coatings exist, and one widely sold product is designed for EPDM, TPO, metal, aluminum, fiberglass, and wood with no primer needed. Treat that claim as manufacturer-specific: it applies to that maker’s own product and prep method, not to every coating on the shelf.
The Comparison: Three Kit Types Side by Side
Coverage is measured per gallon, per coat, and the systems below all require two coats applied at right angles to each other. Buy on square footage, not on the size of the box.
| Kit Type | Typical Contents & Coverage | Critical Prep Step |
|---|---|---|
| EPDM rubber kit | Dicor RP-RRK-30: 4 one-gallon pails of EPDM acrylic coating, 2 quarts cleaner/activator, 4″×50′ cover tape, roller and pan | Apply EPDM primer and let it dry 1–2 hours |
| Fiberglass kit | Dicor RP-FRC-1: 1-gallon white coating, 350 sq ft per gallon per coat | Clean with a fiberglass clean-and-prep product, abrade lightly, rewash |
| Metal roof kit | Dicor RP-MRC-1: 1-gallon coating, 200 sq ft per gallon per coat | Remove rust to bright metal, prime with rust inhibitor |
| Universal coating | Single-product systems with maker-stated multi-roof compatibility | Follow that maker’s prep instructions exactly |
If you want a side-by-side look at what people actually install, our roundup of top coatings for an RV roof compares the field directly.
Prep Rules That Decide Whether the Coating Lasts
Prep is where most jobs fail, and every manufacturer treats it as non-negotiable. The surface must be clean and dry, free of dirt, silicone, loose paint, rust, oil, grease, coal tar, and other contaminants. Dicor’s own guidance goes further: reseal fasteners and roof protrusions one to two weeks before coating, if they need it.
Work the details in this order:
- Clean the roof thoroughly and let it dry completely.
- Remove rust down to bright metal on metal roofs, then prime those spots.
- Seal joints and seams with coating-ready cover tape, and seal around vents and protrusions with seam tape or caulk.
- Apply the base coat or primer the manufacturer specifies, and let it dry.
- Roll on two full coats at right angles, letting each dry before the next.
Coverage math matters here. Dicor’s metal coating covers 200 square feet per gallon per coat; its fiberglass coating covers 350. A 30-foot unit needs more product than a 20-foot one, and running short mid-job leaves a roof coated in patches.
Weather, Cure Time, and Seam Details
Temperature and timing can wreck an otherwise correct application.
Seam tape gets encapsulated with a heavy detail coat extending at least 1 inch past the tape edges. Additional coats go on 6–8 hours apart, or until dry to the touch. Roll with a 3/8-inch medium nap roller rather than a foam one, on a roof that is completely dry.
Clean tools with soapy water immediately after use — dried coating ruins rollers and brushes for good.
Common Questions
Can I use one coating on every roof type?
Only if the manufacturer explicitly states that compatibility for that specific product. Some coatings are sold as suitable for EPDM, TPO, metal, aluminum, fiberglass, and wood, but that claim is tied to that maker’s own prep method. Dicor keeps EPDM, fiberglass, and metal systems separate, so the safe habit is matching the kit to your roof material.
How much coating do I need for my RV?
Measure your roof’s square footage and divide by the coverage rate of the product you chose. Dicor’s metal coating covers 200 square feet per gallon per coat and its fiberglass coating covers 350. Two coats are required, so double the total. A 30-foot unit typically needs a multi-gallon kit rather than a single pail.
What happens if I coat a dirty or damp roof?
The coating can lift, bubble, or peel within a season. Manufacturers require a clean, dry surface with no dirt, silicone, loose paint, rust, oil, grease, or coal tar. Rain or high humidity within 4 hours of application can also ruin the bond, which is why dry weather and 50°F or warmer matter so much.
Sources
- Dicor. “Elastomeric Metal RV Roof Coating.” Supplies the metal-roof prep steps, coverage rate, and rust primer part numbers.
- Dicor. “Fiberglass RV Roof Coating.” Supplies the fiberglass prep steps and the 350 sq ft per gallon coverage figure.
- Ames Research Laboratories. “RV Roof Coating Kit.” Supplies the kit contents, price, and five-step application sequence.