Overview Usage Product Specifications Handling Precautions

Waterproofing Membrane


TRU PU is a single component waterproofing Liquid membrane, elastomeric membrane, it is bitumen modified polymer PU based waterproofing system. PU waterproofing membrane gives excellent barrier to building facades from vapour, salts and water

  • Waterproofing of wet areas, foundations, basements, terraces, retaining walls, inverted roofs etc
  • For waterproofing terrace garden and podium
  • Other roof structures when protected from exposure to direct sunlight, for longer life
  • TRU PU is a single component liquid system and very easy to apply
  • High elasticity ensures a permanently flexible barrier over a wide range of temperatures
  • Outstanding resistance to oxidation and brittlement
  • Gives better adhesion. Can be applied to a range of substrates
  • Good crack bridging capacity up to 2 mm
  • Good retention capacity
How to use
How to use
  • Clean the surface by manual & mechanical means, remove all the loose material or previous work done, make it free from any type of contaminants like oil, sand, debris etc
  • Prime the surface with max. 20% water adding to Tru PU. Mix it till it becomes Homogeneous, then apply by brush or roller to the surface. The coverage will be approx. 80-90 sq ft per Kg. The coverage will depend on the substrate condition.
  • Tru PU undiluted should be applied direct by brush to obtain a continuous unbroken film
  • Two coats are required, second coat should be applied at right angles after the first coat has cured properly
  • It must be protected from mechanical damage during construction or backfilling works
  • Any damage may be repaired by spot application
  • If a water flood test is to be run, the membrane should cure for a minimum of 10 days
  • Tru PU is resistant to frost but adhesion will be weak if it is applied to frosted substrates/surfaces
  • Application should be avoided if substrate temperatures are below 5ºC or rain forecast. For any further technical information please contact the Astral Technical Services Department


Appearance In House Viscous Liquid
Colour In House Black after Drying
Specific Gravity at @25°C IS:101 (P-1/S-7):1987 1.07 ± 0.02 g/cm³
Viscosity at @25°C ASTM D 2196 10000 ± 2000
Cure Time   24 Hour approx. (Complete Curing 7 to 10 days)
Tensile strength at Break ASTM D 412 >1.5 N/mm²
Elongation at break ASTM D 412 ≥ 600 %
Crack Bridging InHouse Up to 2mm
Shore A Hardness InHouse 35 - 45
WFT LDM 1000 – 1200 micron
DFT LDM 500 – 600 micron


  • 1 sq mtr @ 1.1 to 1.2 kg of Tru PU in 2 Coats
  • Coverage Depends on type of Substrate and its porosity
Shelf Life
Shelf Life

12 months from the date of manufacturing.


Product should be stored in a dry place in their original, properly closed containers at temperature between 2-40°C. Partially emptied container should be closed immediately.

  • Packing

    1 kg & 20 kg

Handling precautions

Mandatory and recommended industrial hygiene procedures should be followed whenever our products are being handled and processed. For additional information please consult the corresponding product data sheets and the brochure “Hygienic precautions for handling plastics products”.




  • For Primer, the product should be diluted with water (20% maximum by weight, i.e. 4 kg of water for 20 kg of TRU PU at site to achieve a workable consistency)
  • Water ponding test shall be done only, once the coating is fully cured for 10 days
  • After full cure, This Product will be slightly tacky, hence it is recommended to use a separation layer such as geotextile or PE sheet, Then cover with a protection screed
  • Outgassing is a naturally occurring phenomenon of concrete that can produce pinholes in subsequently applied coatings. The concrete must be carefully assessed for moisture content, air entrapment, and surface finish prior to any coating work. Installing the coating either when the concrete temperature is falling or stable can reduce outgassing. It is generally beneficial, therefore, to apply the embedment coat in the late afternoon or evening
  • For optimum application, do not allow liquid TRU PU to be heated by direct sunlight or other heat sources
  • Not suitable for permanent water immersion, hence not recommended for water-retaining structures such as RC tanks, swimming pools, water features, etc.
  • The 1st coat and 2nd coat of TRU PU should be applied without any dilution & only primer need to be diluted.
  • During the curing process micro bubbles are formed. This is a product characteristic, which does not affect the protective properties. For this reason, it should be ensured that the material is not applied at excessive film thicknesses in one layer. Excessive film thickness may create bubbles
  • The product can be applied by brush, roller or airless spray. Work well with a brush in difficult areas. Apply subsequent layers 24 hrs after the application of first layer
  • If TRU PU has been exposed to UV light, its colour will be changed to yellow slightly without losing its physical properties but flow is possible due to temperature of sun light in open to sky condition.
  • It is recommended to use a reinforced coating system with 45 gsm fleece or fibre net specially on the Joints/corners etc to increase its tensile property. however, the performance of a standard coating system is also excellent
  • A screed needs to be laid on the finished system
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