Liquid EPDM Rubber vs. Neoprene Rubber for waterproofing concrete pipe and vessels.

EPDM rubber was not available in liquid form until relatively recently so Liquid Neoprene rubber became the material of choice for protecting concrete against both fresh and salt water. The Liquid Neoprene products are simple solvent solutions or water based emulsions and therefore have low solids content and relatively low molecular weights. These limitations made multiple coat applications necessary and required top coating with other polymers to prevent ultra violet degradation.

The development of Liquid EPDM Rubber resulted in a high solids, two components chemically reactive product capable of polymerizing at ambient temperatures( 55 F ( 13 C) and higher). This product can be applied at a 30 mil dry film (.76 mm) in a single application because of the high solids content. Its chemical cure feature then results in a high molecular weight film with protective and performance properties exceeding those of liquid applied Neoprene films.

Liquid EPDM Rubber can withstand boiling water or live steam and is inherently UV and ozone stable. The product is safer to use because of its higher flash point and the two component packaging permits extended storage at higher temperatures than liquid Neoprene. The non polar characteristic of the EPDM also gives it advantages over Neoprene in saltwater environments as well as better resistance to cathodic disbondment.

EPDM rubber has poor resistance to oils, fats, waxes and aliphatic solvents but possesses very good resistance to ketone solvents, alcohols, polar compounds, Salts, most acids up to 50 % concentration, alkalies and water.

Advantage of Liquid EPDM Rubber.

  • One coat application.
  • UV and ozone stability.
  • Higher flash point ( 105 F ; 40 C).
  • Storage stability at higher temperatures .
  • Can be used in extreme environments.
Liquid EPDM Liquid Neoprene
Product Description Two component ambient temperature cure One component solution or emulsion
Solids content( by Volume)              60-65 %        less than 30 %
Flash Point             105 F ( 40 C )          50 F ( 10 C)

(solvent solution)Tensile strength 600-800 psi ( 42-46 kg/cm)   1600 psi (112 Kg/cm)Elongation               150 – 200 %              450 %Temp. tolerance range              -60 to 300 F

-76 to 149 C          -40 to 200 F

-40 to 93 CMax dry film per coat                 30 mils

.76 mm             4-6 mils

.1 to .15 mmUltra violet stability                Excellent    Recommended top

coatingsWater resistance

fresh water

sea water

excellent to 275 F (135 C)

excellent to 180 F (82 C )

Very good to 200 F ( 93 C)

excellent to 212 F (100 C)

excellent to 70 F (10 C )

Oil resistance                  Poor            Very goodHydrogen sulfide


(wet) resistance            Very good            Very goodCoverage          960 sq.ft/gal/mil

8.57 sq.m/l/mm       417 sq.ft/gal/mil

3.7 sq.m/l/mmSpecific gravity                  1.05 volatile organic

compounds              333 gr/l            600-610 gr/l

Coating Cast Concrete

Concrete which has not been  trowel finished will have a surface that is more porous   than one which has been trowelled. When Liquid Rubber is applied directly to such a porous surface it will produce a high density of small craters in the resulting membrane. This is caused by the fact that Liquid Rubber actually penetrates into the pores, leaving a crater on surface . The following  procedure is recommended to prevent formation of surface craters:

1) Apply a light coat of one of the following products to seal the surface :

a.) Water based acrylic elastomeric coating( primer or base -coat version)

b.) Solvent based chlorinated rubber or Hypalon product.

c.) Solvent based neoprene product.

The choice of water  or solvent based product should be based on temperature and  humidity conditions. For water based products, relative humidity should be less than 70% and temperature 60 degrees or higher. Solvent based products should be used  at low temperatures and high relative humidity.

2) Liquid Rubber may be applied when primer application is sufficiently dry. Water based products should be allowed to dry thoroughly, as any surface moisture will interfere with  the adhesion of the rubber. A single coat of Liquid Rubber is preferable to multiple coats.

  • Testimonials

    • Dave H.

      Overall, I am impressed with the results I obtained in using Liquid RV roof on my trailer. It was MUCH easier than replacing the membrane with new, and seems to have repaired my leaking roof, extending the life of my RV, as at some point, the cost of reroofing would exceed the RV’s value. Thanks in advance!

    • Mike H.

      My roof was in bad shape. I cleaned it and kept after it a few times a year. We bought the RV used, and there were signs of neglect when we bought it. It had been obviously sitting in the sun for an extended period of time without any care or maintenance. I was about to buy a sheet of EPDM and forego the labor intensive and very expensive task of replacing the sheet roof. Then I saw a video on Youtube for Liquid EPDM. So the research began. “This… Read more

    • Tom Pituch

      I was able to quickly find the 2 pictures I took after I patched the roof. I will continue to look for the before pictures, We have a flat roof with a channel down the middle that leads into a drain pipe system that has been our weak point area all along. Then we installed a sky light which was like adding gasoline to a fire. For years I was blaming the sky light that we installed. We even replaced portions of the sky light and sealed around it many… Read more

    • Bob & Sally H.

      The two pictures are the before and then after using your product Liquid Rubber. Very pleased with the way it turned out! And also the shipping sure came quickly. Have a great and safe day! Bob & Sally H.Yuma AZ

    • Rick M.

      The epdm rubber roof was easy to work with. I am very pleased after having a leaky roof that will be good for many years to come. Roof had mold on it so we first killed the mold with Clorox and water and scrubbed I down and then cleaned the roof with Dawn dish detergent. Attached are the before and after pictures. ThanksRick M.

  • Contact

    EPDM Coatings N.E Sales Office
    494 Bridgeport Ave Suite 101,
    PMB 342 Shelton CT 06484-4748
    Call: 610-298-1989, Fax: 702-977-2936
    Proud Distributor of Proguard Coatings
    Tel: 1-610-298-1989
    Email: [email protected]
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