Frequently Asked Questions

Black is our toughest, true-waterproof coating — the heavy-duty choice for foundations, ponds and demanding jobs where water sits against the surface, and it’s proudly made in the USA. White is a reflective coating that helps bounce heat off roofs, and Gray gives a neutral finish; White and Gray are our popular everyday colors for roofs and surface protection.

Yes. Rubberseal bonds well to clean, dry wood, plywood and OSB, sealing and waterproofing the surface.

Yes. Clean the surface and brush off any loose rust or scale before applying.

Yes. We also offer a trowel-grade caulk and sealant for filling cracks and detailing.

Yes — just use a flexible, quality exterior paint or coating. Rubberseal stays flexible, so a rigid paint may crack over it. You can also apply foam insulation with a finish over a cured foundation coat.

Full cure is typically about 72 hours. Warm, dry conditions speed it up, while cold or very humid conditions slow it down. Don’t apply if rain is expected within about 6 hours.

For a full waterproof membrane, build up to the recommended thickness — usually two or more coats. For heavier-build areas (around 80 mils) plan on roughly 4–5 coats. Reinforce cracks, seams and transitions (such as around a skylight) with Rubberseal Geotextile fabric embedded between coats.

Yes. Rubberseal cures into a highly flexible, crack-bridging membrane that stretches and flexes with movement instead of cracking, and recovers its shape well.

Yes. Once Rubberseal is cured, thinset can be applied directly over it — it works well as a waterproofing layer under tile to keep water off the backer board.

Yes. Rubberseal is well suited to bathroom and shower waterproofing as a waterproof layer behind tile or on a shower base. It isn’t a finished surface itself, so tile or another finish goes over it.

Yes. Rubberseal is flexible once applied and seals around vents, seams and penetrations. It can also be applied over a clean, aged EPDM membrane — power-wash and dry it first — and bonds well directly to clean plywood.

Yes. Rubberseal can coat and waterproof the exterior of a plywood boat, and the bond strengthens as it cures. For boats, call technical support first — hull immersion and abrasion are demanding uses.

Yes. Rubberseal bonds to clean concrete and forms a seamless waterproofing membrane on foundations, shower bases and similar structures. Use Black for below-grade and water-holding applications.

No — Rubberseal isn’t designed for driveways or other vehicle-traffic surfaces.

If you need a thick, impact-resistant bed liner like a spray-in product, Rubberseal isn’t the right choice for that use.

A fresh coat can feel tacky at first, and that fades as it cures. To speed it up, dust the surface lightly with talc or baby powder.

Our Black liquid rubber products are proudly made in the USA.

You can buy Rubberseal direct from this website, on Amazon, or at The Home Depot (online and ship-to-store) — the same contractor-grade liquid rubber, wherever you prefer to shop.

Coverage is about 32 sq ft per gallon at 40 mils for a full waterproofing build, or roughly 130–150 sq ft per gallon for a thin protective coat at 10 mils. Use our coverage calculator to estimate how much your project needs.

Use roll-on (or brush) Rubberseal to coat broad surfaces — roofs, foundations, ponds and walls — building a seamless membrane. Use the trowel-grade caulk and sealant to fill and detail cracks, seams, flashings and low spots. Many projects use both together.

We publish cure times and film build rather than fantasy numbers. Applied properly at a full membrane thickness — about 40 mils, and at least 60 mils where water will stand — Rubberseal cures into a durable, long-service membrane, and it's recoatable, so you can refresh it over time without tearing anything out. For project-specific questions, call technical support at 866-607-6826.