Liquid EPDM Coatings are aftermarket roof sealants


A number of aftermarket roof sealants are available, including urethanes, acrylics and liquid rubber. Liquid EPDM rubber is by far the most durable of the sealants available and has the widest range of applications.

It is more water resistant than other rubbers, including neoprene. It is more resistant to swelling and has a wider range of acceptable temperatures. It can be applied directly to practically any roofing material other than asphalt and can even be used on wood that has been primed.

Liquids have an obvious advantage over sheets. Sheets have seams. Seam sealers eventually deteriorate and water gets through the seams and under the sheeting.

Liquid EPDM can be used on top of neoprene, although some pre-treatment of the surface is required. Just knowing that the liquid rubber is recommended for use on top of the other type of rubber should be an indication that the material is more durable.

Liquid EPDM can also be used on top of polyurethane after a light sanding. It is somewhat surprising that urethanes are still used as aftermarket roof sealants. It is known that the structure is damaged by UV light and that discoloration occurs relatively quickly. Anyone who has made the mistake of using urethane as a roof sealant should consider applying liquid EPDM to truly protect the roof.

The liquids can also be used to seal existing leaks. They are self-adhering and fill up tiny fractures that let water through. It is a good idea to use a thick coat and cover the entire surface instead of attempting to only cover the leaky area.

When covering the entire roof, the liquid rubber reduces heat buildup. Not only does the roof stay cooler, but the interior of the building or the vehicle will also stay cooler. This benefit may reduce heating costs and keep the occupants more comfortable.

Liquid EPDM has become the most popular choice for RV roofs, because of all the above-mentioned advantages. It extends the lifespan of the roof and requires less maintenance. It lasts up to three times longer than any other aftermarket RV camper rubber roof sealant and also reduces noise from rain.

As far as price goes, most sealants are similar in price. Depending on where you buy, EPDM may be a little more expensive, but because primers and additional coats are not usually necessary, and because it lasts so much longer, owners who choose this aftermarket roof sealant save money in the long run.

Technical Aspects of EPDM


Elastomeric coatings are roofing applied in a viscous state. It has elastic properties, and can stretch in the summer time heat and then return to their original shape without damage.

Elastomeric coatings usually contain polymeric materials, such as acrylic, and a white pigment, such as titanium dioxide, to make them opaque and reflective. An elastomeric coating is applied thicker than paint. An elastomeric coating can be used on virtually any substrate including asphalt built-up roofing, concrete roofing, metal roofing, modified bitumen roofing, polyurethane foam roofing and single ply roofing.

Since EPDM Liquid Rubber Coatings cures by chemical reaction, a single heavy application will be preferable to multiple thin coats. A second coat will bond to a previous film but that bond will not be as strong as the internal bond within each layer. If a second coat is applied before the first has thoroughly cured, some wrinkling may result as the first coat absorbs solvent and swells. This will, however, recover as the solvent evaporates. It is generally recommended that only a single coat be applied over non-porous surfaces, the thickness of which can be varied as desired. Thicker films will take longer to cure through. Asphalt coatings and asphalt built-up roofs are considered unstable substrates and therefore, not recommended for coating directly with Liquid Rubber EPDM. EPDM COATINGS do carry a specific elastomeric which with a two coat application gives you a 10 year warranty.

Liquid Rubber is designed to re coat structurally sound existing roof and protective materials. They are also best for RV Roof Repair. They should not be used in place of roofing membranes”.

The following are recommended substrates to coat:

  • Metal – Coated or Galvanized Steel
    • Weathered Aluminum
    • Weathered Copper
  • EPDM Rubber membrane
  • Concrete (except foot traffic surfaces)
  • Urethane Foam
  • Primed Wood
  • Fiberglass
  • PVC Sheet and Pipe
  • Acrylic Sheet
  • Sponge Rubber insulation

Do Not use Liquid Roof or Liquid Rubber on the following substrates:

  • Built up asphalt roofs
  • Asphalt shingles
  • Modified asphalt roll roofing
  • Stainless steel
  • Glass
  • Silicone caulk
  • Foot traffic surfaces
  • Hypalon Membrane

EPDM Roof Repair/maintenance


Low Maintenance EPDM Roofs: EPDM is a kind of synthetic rubber that can be used for waterproofing or roof leaks repair of all kinds. The material is commonly used on top of metal roofing found in RVs, trailers and some homes.


There are two forms of EPDM. The foil or sheet form is typically used for waterproofing new roofs. The sheets are often recommended for flat roofs in commercial type buildings. It can be used on trailers and houses too but some people don’t like the appearance.


The other type is a liquid. There are several advantages to the liquid type.

The first advantage is durability. The liquid type may help the roof last even longer because there are no seams that could be a target for water pooling and eventually rust.


An adhesive must be used to install the sheets. The liquid type is a “self-adhesive”. It only needs to dry to hold itself in place.

The liquid is easy to apply. It takes only a single coat. There is no need to use a primer or other coats. You need only ensure that the roofing is clean and dry before pouring on the EPDM.


Both types are resistant to practically any temperature that occurs here on earth. Whether it is 40 below zero or 250 degrees Fahrenheit, there is no risk of melting, cracking or peeling.


The curing time and the temperature needed for curing are considerations for the liquid type. They are not necessarily disadvantages unless you live in a climate that is below 55 degrees day and night year round.


The liquid cures through a catalyst chemical reaction. In order for the reaction to occur, a daytime temperature of 55 degrees or higher is necessary. Very high temperatures could also interfere with the curing process. This is a job best done during late spring, early summer or early fall in many parts of the country.


The liquid EPDM can also be used to repair existing EPDM roofs. If only a small area of the sheeting is damaged or needs to be replaced, it may be more cost effective to use sheeting for repair, as long as you can find a small amount of sheeting. Many hardware stores carry patching kits and you can also find them on the internet.


Very little maintenance is required for the rubber roofing. A seasonal check to ensure that no branches or other debris have deteriorated the coating is about all you need to do.