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

    • Paul

      Hi Everyone, I completed my project and it was much easier than I thought, I wish I had done this years ago, and glad I chose this coating versus the other offerings out there. I will send you 2 more emails, this is the start of cleaning, next is primer, the third is the coating. Hope they are worth of a gift card. Thanks

    • Fred D.

      EPDM is amazing. My RV roof was a disaster. I have been battling leaks for a few years now and no other product would stop the leaks or even last more than a few months. Everything else would peel up after awhile. I used the EPDM with the primer. It rained a week later. Zero leaks! The product goes on easy and covers well. No cracks no bubbles. I am very satisfied and would recommend this product to anyone. The are so many products out there and skepticism runs high…. Read more

    • David R. D

      Just a great product, went on easy and looks great. Just completed my 35 Bus, cut in the rap around sides and around the ACs and vents. Spent the hardest time on cleaning and prep. If you are looking for a product to seal your RV stop looking !!!! David R. DLincolnton GA

    • Stephen L

      Let me tell you this stuff if fantastic. I replaced my roof several years ago and white rubber was not available at the supply company, it was out of stock and I had to replace the rubber as I had ripped the old off. The black rubber made it miserable in here. I did a lot of research looking for a good quality coating that would last and hold up to the elements. I found your product and was convinced, so I ordered and have now applied. I did not… Read more

    • 5000 sq ft concrete roof

      5000 sq ft concrete roof. Prep work consisted of power wash of roof and preparation of seams as see in “before” picture. Approximately 7 sets of ProFlex primer was used and 28 Pails of Liquid EPDM Rubber. Cost per sq ft approx. $1.66 . Life expectancy is 18-20 before a recoat is needed.

  • Contact

    EPDM Coatings N.E Sales Office
    494 Bridgeport Ave Suite 101,
    PMB 342 Shelton CT 06484-4748
    Fax: 702-977-2936
    Proud Distributor of Proguard Coatings
    Tel: 1-610-298-1989
    Email: info@epdmcoatings.com
Full Stocking Distributor of Proguard Coatings
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