Waterproofing Membranes, Isothane EM Range

EMB Elastomeric

Structural Waterproofing


EMB elastomeric membrane is a liquid applied coating based on polyurethane prepolymers extended with tar, which cures by reaction with atmospheric moisture to give a continuous film that is rubber-like and elastic.

EMB is a high solid coating designed to give a high-build film. It can be applied by brush or squeggee but it has a higher viscosity than a conventional paint and should not be diluted.

EMB complies with coatings standard ASTM C836; Standard Specification for High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane for Use with Separate Wearing Course.

It cures to a permanently flexible seamless membrane that, by virtue of its chemical reactivity in the wet state, has good adhesion to a wide range of substrates. Unlike more traditional bitumen based products, EMB does not readily embrittle with age, exposure to ultra violet radiation or weathering, and hence it does not crack or craze ( European conditions ).

Since it is elastomeric EMB is not adversely affected by extremes of temperature consequently it is resistant to cracking at low temperatures and does not suffer thermal flow at elevated temperatures.

Isothane elastomeric membranes are designed to bond to many types of substrate particularly those commonly requiring a waterproof membrane in ‘tanking’, above and below ground, and internal wet area sections of buildings. It is essential that the substrate and structures are properly prepared, and stable. Surfaces previously treated with silicone-based materials will inevitably be difficult to overcoat and this should not be attempted with Isothane products.

EMB can be applied by brush, squeggee or roller without the need to mix, stir or heat before application.

Technical Data

Storage, Handling and Personal Protection

The recommendations in our Safety Data Sheet for this product must be followed at all times. More general information is included in our publication “A Guide to the Safe Handling of Polyurethane Chemicals” and in the following Technical Data Sheets which are available on request:-

  • Decontamination of Isocyanates using Isothane Decontaminant
 Typical Properties  EMB
 Appearance  Black viscous Liquid
 Abel closed cup flashpoint º C
(ISO 1523, 1983)
 Application limits º C  5 – 60
 Approximate Dry Time (20ºC, 50% RH)  12 – 24 hrs touch dry, 7 days full cure
 Elongation % (ASTM D412) minimum  500
 Tensile Strength MN/m² (ASTM D412) minimum  2.0
 Accelerated Weathering 12000hrs
(ASTM 953)
 No appreciable deterioration
 U/V Resistance ( European Conditions )  Excellent
 Hydrolysis Resistance  Excellent
 Resistance to Industrial Environments  Good
 Resistance to Industrial Environments  Good
 Storage Stability (temperateclimate)  6 months

Tested to ASTM C836-05

Hardness (Shore 00 / A) 90 / 50
Low temperature Flexibility Crack Bridging No cracking
Adhesion-in-Peel (mortar) 6.5 lb/in
Extensibility after Heat Aging No cracking

Water Vapour Permeability

Free films were prepared and allowed to cure for 28 days prior to test. The water vapour permeability was measured using the dry cup method under tropical conditions of 38º C and 90% rh as described in ASTM E96-05

Result: 22.2 g/( m²/24h)/1mm

Crack Bridging Ability (ASTM 836-84m)

Result: 2.6mm (20º C, 0.4mm thick EMB)

Penetration by Fire & Surface Spread of Flame Resistance

Result: EXT.F.AA. (BS476: Part 3)




Structural Waterproofing

Our high performance structural waterproofing products offer heavy duty resistance to ponded water & UV light.


Case Studies

Structural Waterproofing EMB High Performance Structural Waterproofing

the client Malta’s prestigious Tigne Point commercial, residential and leisure development. the problem A durable, high specification structural waterproofing and...


EMB Waterproofing EMB High Performance Weatherproofing

the client Chemical manufacturing plan in the United Kingdom the problem Insulated outdoor bulk chemical storage tanks required a weatherproofing...


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Prepolymers & Export Enquiries

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