One-component, rapid-curing, polyurethane, liquid waterproofing membrane for flat roofs. Based on elastomeric, hydrophobic polyurethane resins, ISOFLEX PU 500 A features excellent mechanical, chemical, thermal and weather resistance. Thanks to its unique formulation, it cures rapidly to form a thick, bubble-free membrane. It offers the following properties:

• Forms a continuous, elastic, waterproof, vapor-permeable membrane, without seams or joints.
• Shows excellent adhesion to various substrates, such as concrete, cement mortars, wood and most waterproofing layers.
• Applicable even on irregular substrates and at low temperatures.
• Maximum consumption can be achieved in only one coat reducting labor costs.
• The membrane becomes quickly rainproof.

Certified according to EN 1504-2 and classified as a coating for surface protection of concrete. CE marked. Certificate No.: 2032-CPR-10.11. In addition, the product has been successfully tested according to the requirements of EAD 030350-00-0402 and is classified as: W3, S, TL4-TH4, P4 special, which means  that its expected working life is 25 years under the worst control conditions specified in this standard concerning user loads (P4), the climatic zone (S) and the resistance to maximum and minimum service temperatures (TL4-TH4).

ISOFLEX-PU 500 A is suitable for waterproofing:

• Roofs, flat roofs and balconies, as exposed waterproofing membrane.
• Gypsum and cement boards.
• Under tile layers in kitchens, bathrooms, balconies and flat roofs, as long as quartz sand has been broadcast on its last layer.
• Under thermal insulation boards on flat roofs.
• In construction works, such as highways, bridge decks, tunnels, etc.

Substrate preparation
In general, the substrate must be dry (moisture content <4%) and free of grease, loose particles, dust, etc.

1.1 Concrete surfaces
Any existing cavities in concrete should be repaired in advance. Severe cracks in the substrate must be primed locally and after 2-3 hours (depending on the weather conditions) must be sealed with the polyurethane sealants FLEXPU-30 S/50 S.

1.2 Smooth-Non absorbent surfaces
Smooth and non-absorbent surfaces, as well as surfaces with bituminous membranes or other old waterproofing layers, must be primed with the water-based wpoxy primer EPOXYPRIMER-500, thinned with water up to 30% by weight. The product is applied by brush or roller in one coat. Depending on the weather conditions, ISOFLEX-PU 500 A is applied within 24-48 hours from priming, as soon as the moisture content falls below 4%.

Application- Consumption
Before application, it is recommended to slightly stir ISOFLEX-PU 500 A until it becomes homogeneous. Extensive stirring should be avoided though to prevent air entrapment.

a) Total waterproofing of the surface without reinforcement
ISOFLEX-PU 500 A is applied by brush or roller in two layers. The first layer is applied 2-3 hours after priming and while PRIMER-PU 100 is still tacky. The second layer should be applied crosswise after 4-5 hours. 

b) Total waterproofing of the surface with reinforcement
ISOOFLEX-PU 500 A membrane is reinforced with 100 cm wide polyester fleece strips (60 g/m2 or 120 g/m2). These placed strips must overlap by 5-10 cm. In that case, 2-3 hours after priming, about two thirds of the required quantity is poured onto the floor and as soon as the material is spread, the polyester fleece is placed o it and then is rolled in, in order to help release the entrapped air. Then, the remaining content is poured over the fleece and is spread with a roller.

c) Local waterproofing of cracks with reinforcement
In this case, the primer is applied on the substrate, only along the cracks to a width of 10-12cm. Two-three hours after priming, about two thirds of the required quantity of ISOFLEX-PU 500 A is poured and while this is still fresh, a 10 cm wide polyester fleece strip (60 g/m2 or 120 g/m2) is placed on it and is then rolled in to help release the entrapped air. Then, the remaining quantity is poured over the fleece and is spread with a roller.