Dicor sells a different roof coating system for each kind of RV roof, and each system starts with its own cleaner or primer. Using the wrong pair is the usual reason a coating peels. This guide covers which Dicor products go on which roof, how much to buy using Dicor's published coverage rates, and Dicor's one-day application schedule.
Which Dicor coating for which roof
| Roof | Step 1: prep | Step 2: coating |
|---|---|---|
| EPDM rubber | Cleaner/Activator Part 1 (RP-CRP-Q) | Acrylic Coating Part 2 (RP-CRC-1 white, RP-CRCT-1 tan), CoolCoat (RP-IRC-1) or Signature silicone (RP-SELRC-1) |
| PVC | Cleaner/Activator Part 1 | Acrylic Coating or CoolCoat |
| TPO | Dicor TPO Silicone Roof Primer (RP-TPR-Q), which we don't stock yet | Signature silicone |
| Fiberglass | Fiberglass Clean & Prep (RP-FCP-1) | Fiberglass RV Roof Coating (RP-FRC-1 white, RP-FRCT-1 tan) |
| Metal | Metal Roof Rust Inhibitive Primer (RP-MRRIP-Q) | Elastomeric Metal RV Roof Coating (RP-MRC-1) |
Dicor's catalog marks the Cleaner/Activator, Acrylic and CoolCoat "EPDM & PVC use only", the TPO primer "TPO use only" and Signature "EPDM & TPO use only". Dicor's fiberglass prep, fiberglass coating and metal primer are "not recommended for EPDM rubber or TPO roofing". Dicor's fiberglass, metal and Roof Renew Kit directions seal roof seams, cracks and tears with Coating-Ready Cover Tape (4 in x 50 ft) before coating; Dicor says the tape must be followed by two coats and applied only to areas you will coat the same day. Dicor also says the roof must be in good condition: don't coat brittle roofing or membrane you can pry up.
The coatings differ in what they add. Dicor describes the standard Acrylic as a high-solids acrylic elastomer. CoolCoat is an acrylic with ceramic MicroCells; Dicor says its lab tests showed it cut heat flux from the roof into the RV by 29%, with the interior ceiling at 76°F when the roof was at 107°F. Signature is a 100% silicone coating; Dicor's catalog says it dries to the touch in 1 hour and is walkable in 2.
How much to buy
Dicor's published coverage rates:
- Cleaner/Activator: 1 quart per 125 sq ft.
- TPO Silicone Roof Primer: 1 quart per 225 sq ft.
- Acrylic, CoolCoat and Signature: 1 gallon per 125 sq ft per coat, minimum two coats. Dicor's example: an 8 ft x 30 ft roof takes 4 gallons.
- Fiberglass RV Roof Coating: 350 sq ft per gallon per coat, two coats.
- Elastomeric Metal Coating: 200 sq ft per gallon per coat, two coats. The rust inhibitive primer is also applied at 200 sq ft per gallon per coat, two coats, on the cleaned, rust-removed areas (it is sold in quarts).
Measure your roof's length and width and multiply. The table below assumes an 8 ft wide roof, the width in Dicor's own example; wider roofs need proportionally more. Totals are rounded up to whole containers.
| Roof length (8 ft wide) | Area | Cleaner/Activator | Acrylic, CoolCoat or Signature (2 coats) | Fiberglass coating (2 coats) | Metal coating (2 coats) |
|---|---|---|---|---|---|
| 25 ft | 200 sq ft | 2 qt (1.6) | 4 gal (3.2) | 2 gal (1.14) | 2 gal (2.0) |
| 30 ft | 240 sq ft | 2 qt (1.92) | 4 gal (3.84) | 2 gal (1.37) | 3 gal (2.4) |
| 35 ft | 280 sq ft | 3 qt (2.24) | 5 gal (4.48) | 2 gal (1.6) | 3 gal (2.8) |
| 40 ft | 320 sq ft | 3 qt (2.56) | 6 gal (5.12) | 2 gal (1.83) | 4 gal (3.2) |
Math: coating gallons = area x 2 coats ÷ coverage per gallon; activator quarts = area ÷ 125. Dicor adds that actual use depends on the surface, its texture, how you apply it and the weather, so a spare gallon is sensible on a rough or weathered roof. For a rubber roof up to about 30 ft, Dicor's RV Roof Renew Kit bundles 4 gallons of Acrylic Coating, 2 quarts of Cleaner/Activator, a 4 in x 50 ft roll of Coating-Ready Cover Tape, a metal pan, a 9 in roller, two roller covers and masking tape. Our Dicor roof reseal and coating kits page also has a smaller rubber-roof coating kit and a fiberglass roof coating kit.
The schedule Dicor recommends
| When | What |
|---|---|
| 1 to 2 weeks before | Touch up or replace lap sealant so it cures before it is coated over (Dicor's FAQ says about 2 weeks) |
| 1 to 2 days before | Apply any peel-and-stick patches |
| Coating day, hour 1 | Start only when the roof is completely dry of dew or rain. Mask the sidewalls and caps with plastic sheeting down to the ground, sweep off loose debris |
| Hour 2 | Apply Cleaner/Activator, rinse, and let the roof dry completely |
| Hour 3 | First coat |
| Hour 4 | Let it dry completely |
| Hour 5 | Second coat; allow 4 to 5 hours between the last coat and sunset |
| 24 to 48 hours after | Don't use the RV while the coating cures |
On EPDM, the whole process, from activator to second coat, must be finished in one day. Dicor's handbook explains why: the Cleaner/Activator opens the pores of the EPDM for about five to six hours, and the coating has to go on while they are open.
Applying the Cleaner/Activator (EPDM and PVC)
- Protect everything that isn't roof. Dicor says the activator is for the roofing surface only and may damage other parts of the RV; rinse off any that lands elsewhere.
- Spray a fine mist that leaves the roof damp. If it runs off the roof, you used too much. Don't apply below 40°F.
- Let it stand at least 15 minutes.
- Rinse thoroughly. Dicor recommends a pressure washer of at least 2,000 psi with the tip within 12 in of the roof, starting at the lowest point and working up, then back down. Without one, scrub small areas with a medium-bristle brush and rinse well.
- The roof should look "white" when you're done; Dicor says that shows the surface has been chemically altered. Let it dry completely.
Applying the coating
- Mix each pail for at least 5 minutes.
- Use a medium-nap roller or a brush. Lay the second coat at right angles to the first (Dicor's direction for Signature, fiberglass and metal).
- The first coat must be dry before the second. Dicor's FAQ suggests waiting 1.5 to 2 hours.
- Cover every inch, with no voids, pinholes or blisters.
Weather limits by product
| Product | Dicor's limits |
|---|---|
| Acrylic and CoolCoat | Cure by water evaporation; cool, humid weather slows them. They freeze and become unstable below 32°F within 24 hours (CoolCoat page) or 48 hours (Acrylic page) of application. Don't apply if rain, dew or frost could arrive before they cure. |
| Signature silicone | Surface and air between 35°F and 100°F; not within 5°F of the dew point; store the product at 50 to 80°F for 24 hours before use. |
| Fiberglass and metal coatings | Not below 50°F, and not when rain, cold, darkness or high humidity is expected within 4 hours; at least 2 of those hours should be in direct sun. Second coat after 1 to 2 hours at 70°F and 50% humidity. Full cure in 24 hours. |
Dicor's FAQ also says not to coat in direct sunlight, because the coating can cure too fast and flake, and that a coated roof must stay free of all moisture, including dew, for 48 hours. Bubbles in a fresh coating are a sign moisture reached it.
FAQ
Can I use the acrylic coating on a TPO roof?
No. Dicor marks its Acrylic and CoolCoat systems for EPDM and PVC only. For TPO, Dicor's system is the TPO Silicone Roof Primer plus Signature silicone.
How do I maintain the sealant on a silicone-coated roof?
Dicor names its Ultra Sealant, self-leveling or non-leveling, for upkeep on Signature-coated roofs. See Dicor's sealants compared.
How long does unopened coating keep?
Dicor's FAQ gives one year for unopened coatings and adhesives.
Do I reseal before or after coating?
Before, by one to two weeks. Our guide to resealing an RV roof by roof type covers that step. Everything here is in our Dicor collection. Found it cheaper? We'll beat it.