Name: RAINPROOF PWR 690
Brand: Armstrong Chemicals

Question 1

What is RAINPROOF PWR 690?

Accepted Answer

A two-component, 100% solids, fast-setting hybrid polyurea-polyurethane aliphatic waterproofing coating. Compliant with ASTM C-1250, D-2196, D-1475 and D-570, it forms a seamless elastic membrane with >700% elongation, >30 MPa tensile strength and an expected service life of 30+ years at 1.2–2.0mm DFT.

Question 2

How is RAINPROOF PWR 690 applied?

Accepted Answer

Prime the prepared surface with Shineshield WP 305 waterproof primer (minimum 0.15mm, one coat). Mix Part A and Part B at 1:1 by volume using a low-speed mixer at 300 rpm for 2–3 minutes until uniform. Apply over the primed surface by brush, roller or airless spray at approximately 1.2 kg/m² for 1.2mm DFT. Apply only when dew point is at least 30°C below ambient temperature; avoid application during rapidly rising temperatures or imminent inclement weather.

Question 3

Why is 100% solids important?

Accepted Answer

100% solids by volume means no solvent evaporates from the applied film during curing — the full applied wet film thickness is retained as the cured membrane. Unlike coatings with 58–91% solids, there is no volume loss on cure, so the specified 1.2–2.0mm DFT is the actual cured thickness — not a wet-film thickness that shrinks as solvents leave.

Question 4

Where can RAINPROOF PWR 690 be used?

Accepted Answer

Highway bridge decks, tunnels and foundations; flat roofs, balconies and walkways; thermal insulation board underlays; water retaining structures in power plants; roof waterproofing; marine environments; swimming pools; basement foundations and walls; water storage tanks including potable water; bathrooms and kitchen foundations.

Question 5

What is the recommended full waterproofing system?

Accepted Answer

Armstrong recommends a three-product system: (1) apply Shineshield WP 305 as a polyurethane primer at minimum 0.15mm; (2) apply RAINPROOF PWR 690 as the main waterproofing coat at 1.2–2.0mm DFT; (3) apply Summershield Cool 666 as a solar reflective aliphatic topcoat with SRI index of 112, reducing peak summer room temperature by 12–15°C.

Question 6

What does N/mm² (or MPa) mean on this product?

Accepted Answer

N/mm² (newtons per square millimetre) is the same unit as MPa (megapascal) and measures how much force a material can withstand per unit area — its strength. As a reference, standard structural concrete (M20 grade) has a compressive strength of about 20 N/mm², M30 concrete about 30 N/mm², and high-performance concrete 50–70 N/mm². For adhesion or tensile values, anything above 1.0 N/mm² is considered a strong structural bond — most site failures occur below 0.5 N/mm². Higher values indicate a tougher, more durable material or a stronger bond to the substrate.

Question 7

What does psi mean in the performance data?

Accepted Answer

psi (pounds per square inch) is the US unit for pressure or strength — 1 N/mm² ≈ 145 psi, so 200 psi is roughly 1.4 N/mm² and 500 psi is roughly 3.4 N/mm². It is most often quoted for tile-adhesive shear bond strength under ANSI A118 test standards, where the minimum requirement is typically 150–200 psi and premium adhesives deliver 250–325 psi. Higher psi means the bond resists more sideways force before the tile shears off the substrate.

Question 8

What does % elongation mean and why does it matter?

Accepted Answer

Elongation at break is how far the cured film can stretch before it tears, expressed as a percentage of its original length. A rigid cement mortar has almost 0% elongation and cracks with any movement; standard bitumen coatings sit around 100–200%; premium acrylic elastomeric coatings deliver 300–500%; and polyurethane / polyurea membranes reach 500–1000%+. Higher elongation means the membrane can bridge cracks that open and close with thermal or structural movement without splitting — this is the single most important property for a crack-bridging waterproofing coating.

Question 9

What does Shore A / Shore D hardness mean?

Accepted Answer

Shore hardness measures how resistant a cured rubber, sealant or elastomer is to indentation. Shore A is used for soft, flexible materials — a typical joint sealant is Shore A 25–40 (soft and stretchy), a car tyre is around Shore A 70, and a hard rubber wheel is around Shore A 90. Shore D is used for harder materials like rigid polyurethanes and epoxies, where 60–80 is common. Higher numbers mean a harder, tougher, more abrasion-resistant surface; lower numbers mean a softer, more flexible material that accommodates movement.

Question 10

What does 'low VOC' or 'zero VOC' mean for this product?

Accepted Answer

VOC (Volatile Organic Compounds) are the solvent vapours that evaporate from a coating as it dries — the source of strong paint or solvent smells. High-VOC solvent-based coatings can exceed 500 g/L and require ventilation, PPE and long re-occupancy times. Low-VOC coatings are typically under 100 g/L, and zero-VOC / water-based products are essentially odourless and safe for enclosed or occupied spaces (basements, water tanks, interiors, hospitals, schools). Lower VOC means safer application, faster re-occupancy and compliance with green-building standards like LEED and IGBC.

Question 11

What does viscosity in cps / cSt mean for this product?

Accepted Answer

Viscosity measures how thick or thin a liquid is — the resistance it offers to flow. Water is about 1 cps (centipoise), engine oil around 500 cps, and honey roughly 10,000 cps. A low-viscosity injection resin (100–300 cps) will penetrate hairline cracks and porous substrates deeply; a medium-viscosity coating (500–2,000 cps) can be brushed or rolled without sagging; and a high-viscosity thixotropic sealant will hold its shape on vertical surfaces without slumping. The viscosity value tells you what application method (injection, spray, brush, trowel) the product is designed for.