• Certified for safe use in potable (drinking) water reservoirs.
  • When applied forms seamless membrane without joints or leak possibilities.
  • Resistant to water and frost.
  • Maintains its mechanical properties over a temperature span of -3C to +90C.
  • Remains elastic even at low (frost) temperature
  • Full surface adherence.
  • The waterproofed surface can be walked on.
  • Low cost.


  • Waterproofing of Drinking Water Supply Channels
  • Waterproofing of Drinking Water Pipes
  • Waterproofing of Drinking Water Tanks and Reservoirs.
  •  Odorless waterproofing of Wet Areas (under-tile) in Bathrooms, Swimming Pools, Kitchens, etc.

Used for waterproofing of surfaces in direct contact with potable (drinking) water.
Used for waterproofing of not well-ventilated, Wet Rooms and Wet Areas (bathrooms, kitchens, etc) applied under the tiles, when a odorless, solvent-free coating is required.


1,2 – 1,5 kg/m2 applied in three layers.
This coverage is based on practical application by roller onto a smooth surface in optimum conditions. Factors like surface porosity, temperature, humidity, application method and finish required can alter consumption.


The MARISEAL 300 is supplied in off-white.
Other RAL colors may be supplied on demand.


The MARISEAL 300 is certified according the current European and German legislation for use on surfaces in direct contact with potable (drinking) water, and potable (drinking) water storage tanks.
The MARISEAL 300 conforms with the German Standard (Kunststoffe im Lebensmittelverkehr, par., the Greek
Standard (Codex Aliimentarius, articles. 21,21a,24,26,28) and the current relevant European Union directives. Test conducted following the ELOT EN 1484, prEN 12873-1, prEN 14395-1 standards.
The MARISEAL 300 is certified according the Singapore Standard SS 375:2001 “Suitability of non metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water” and was found conforming. The Singapore Standard SS 375:2001 is an adption of Britsh Standard BS 6920 :2000. The MARISEAL 300 is certified according the BS 6920-1 :2000 and was found conforming.

Technical Data

PROPERTY RESULTS TEST METHOD Composition Polyurethane Resin + Hardener Mixing Ratio A+B = 6:1 by weight

Resistance to Water Pressure No Leak (1m water column, 24h) DIN EN 1928 Elongation at Break >100% ASTM D 412 Adhesion to concrete >2,0 N/mm 2 ASTM D 903 Hardness (Shore A Scale) 70 + 5 ASTM D 2240 Solids Content >100% CALCULATED UV accelerated ageing, in the presence of moisture Passed – No significant changes EOTA TR-010 Hydrolysis (5% KOH, 7days cycle) No significant elastomeric change Inhouse Lab Service Temperature -40C to +90C Inhouse Lab Tack Free Time 6-8 hours Conditions: 20C, 50% RH Light Pedestrian Traffic Time 24 hours Conditions: 20C, 50% RH Final Curing time (ponding test) 7 days Conditions: 20C, 50% RH Chemical Properties Good resistance against acidic and alkali solutions (5%), detergents,seawater and oils.


Surface Preparation

Careful surface preparation is essential for optimum finish and durability.
The surface needs to be clean, dry and sound, free of any contamination, which may harmfully affect the adhesion of the membrane. Maximum moisture content should not exceed 5%. Substrate compressive strength should be at least 25MPa, cohesive bond strength at least 1.5MPa. New concrete structures need to dry for at least 28 days. Old, loose coatings, dirt, fats, oils, organic substances and dust need to be removed by a grinding machine. Possible surface irregularities need to be smoothened. Any loose surface pieces and grinding dust need to be thoroughly removed.
WARNING: Do not wash surface with water!

Repair of cracks and joints:

The careful sealing of existing cracks and joints before the application is extremely important for long lasting waterproofing results.

  • Clean concrete cracks and hairline cracks, of dust, residue or other contamination. Prime locally with the MARISEAL710 Primer and allow 2-3 hours to dry. Fill all prepared cracks with MARIFLEX PU 30 sealant. Then apply a layer of MARISEAL 300, 200mm wide centered over all cracks and while wet, cover with a correct cut stripe of the MARISEALFABRIC. Press it to soak. Then saturate the MARISEAL FABRIC with enough MARISEAL 300, until it is fully covered. Allow 12 hours to cure.
  • Clean concrete expansion joints and control joints of dust, residue or other contamination. Widen and deepen joints(cut open) if necessary. The prepared movement joint should have a depth of 10-15 mm. The width: depth ratio of the movement joint should be at a rate of approx. 2:1
    Apply some MARIFLEXPU 30 Joint-Sealant on the bottom of the joint only. Then with a brush, apply a stripe layer of MARISEAL 300, 200mm wide centered over and inside the joint. Place the MARISEAL FABRIC over the wet coating and with a suitable tool, press it deep inside the joint, until it is soaked and the joint is fully covered from the inside. Then fully saturate the FABRIC with enough MARISEAL 300. Then place a polyethylene cord of the correct dimensions inside the joint and press it deep inside onto the saturated FABRIC. Fill the remaining free space of the joint with MARIFLEXPU 30 sealant. Do not cover. Allow 12 hours to cure.


Prime surfaces, like concrete, cement screed, metal, and ceramic tiles with enough MARISEAL 750 primer (min. 250–300gr/m2). Allow 12 hours to cure.


Stir MARISEAL 300 Component A well before using. Then add the MARISEAL 300 Component B at the stipulated mixing ratio. MARISEAL 300 Component A and Component B should be mixed by low speed mechanical stirrer, for about 3-5min. ATTENTION: The mixing of the components has to be effected very thoroughly, especially on the walls and bottom of the pail until the mixture becomes fully homogeneous.

Waterproofing membrane

Poor the entire MARISEAL 300 A+B mixture, onto the primed and prepared surface and lay it out by roller or brush, until all surface is covered.

Please ensure consumption within the pot life of the product (~30min)! Please do not leave the mixed MARISEAL300A+Bcoating in the pail for long, because the exothermic reaction accelerates the curing and will shorten the pot-life. Directly after mixing poor the mixture on the surface on in smaller pails to minimise the exothermic reaction.

Reinforce with MARISEAL FABRIC at problem areas, like wall-floor connections, pipe-outlets, waterspouts (siphon), etc. In order to do that, apply on the still wet MARISEAL 300 a correct cut piece of MARISEAL FABRIC, press it to soak, and saturate again with enough MARISEAL 300. For detailed application instructions with the MARISEAL FABRIC, contact our R+D department.

After 12-18 hours – but not later than 48 hours –apply another layer of the MARISEAL 300, by using roller or brush. For demanding applications apply a third layer.

RECOMMENDATION: We recommend reinforcement of the entire surface, with the MARISEAL FABRIC. Use 5-10cm stripe overlapping.

RECOMMENDATION: For best results, the temperature during application and cure should be between 5
oCand30OC. Low temperatures retard cure while high temperature speed up curing. High humidity may affect the final finish.

WARNING: The MARISEAL 300 is slippery when wet. In order to avoid slipperiness during wet days, sprinkle suitable aggregates onto the still wet coating to create an anti-slip surface. Please contact our R+D Dept. for more details.


MARISEAL 300 A+B is supplied in 6+1 kg pails. Pails should be stored in dry and cool rooms for up to 9 months. Protect thematerial against moisture and direct sunlight. Storage temperature: 5-30C. Products should remain in their original, unopened containers, bearing the manufacturers name, product designation, batch number and application precaution labels.

Safety measures

MARISEAL300 contains isocyanates. See information supplied by the manufacturer. Please study the Safety Datasheet. PROFESSIONAL USE ONLY

Mariseal 300



The MARISEAL 300 is a liquid-applied, solvent-free, hard- elastic, cold applied and cold curing, two component
polyurethane membrane used for long-lasting waterproofing and protection.

Cures by reaction (cross linking) of the two components

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