ISOFLEX-PU 550 is a two-component, solvent-free polyurethane liquid waterproofing membrane.

• Based on hydrophobic polyurethane resins, it features excellent mechanical, chemical and thermal resistance.
• Forms a continuous, elastic, waterproof, vapor-permeable layer, without seams or joints.
• Has excellent adhesion to a variety of substrates, such as concrete, cement screed, wood and most waterproofing membranes. 
• Applicable even to irregular substrates.
• Ideal for interior use, as it is solvent-free and almost odorless.

Certified as material suitable for contact with potable water, according to the requirements of RD140/2003. Water tanks must be thoroughly washed prior to filling with potable water. Certified according to EN 1504-2 and classified as a coating for surface protection of concrete.

ISOFLEX-PU 550 is suitable for waterproofing:

• Under tiles in kitchens, bathrooms, balconies, roofs and flat roofs, as long as quartz sand has been previously broadcast on its last layer.
• Under thermal insulation boards on flat roofs.
• In construction works, highways, tunnels, waterproofing bridge decks, etc.
• Aboveground and underground concrete tanks with potable water, metal tanks, fire protection tanks, etc.

Substrate preparation
In general, the substrate must be dry (moizture 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 on the substrate must be locally primed and must be sealed with the polyurethane sealant FLEX PU-30 S or FLEX PU-50 S. Concrete and other porous surfaces with a moisture content < 4% should be treated with the epoxy primer DUROFLOOR-PSF, with a consumption of 200-300 g/m2. Application of ISOFLEX-PU 550 should follow with in the next 24-48 hours. Surfaces with moisture content > 4 % should be primed with the special two-component polyurethane primer PRIMER-PU 140, with a consumption of 100-250 g/m2. Application of ISOFLEX-PU 550 should follow after 3-4 hours, depending on the temperature.

1.2 Smooth-Non-absorbent surfaces
Smooth and non-absorbent substrates, as well as bituminous membranes or old waterproofing layers, must be primed with the water-based epoxy primer EPOXYPRIMER 500, thinned with water up to 30% by weight. The product is applied by brush or roller in one coat. 

1.3 Metal surfaces
Metal surfaces should be:

• Dry and clean.
• Free of grease, loose particles, dust, etc. that might impair adhesion.
• Free of rust or corrosion that might impair adhesion.

Having been prepared by brushing, rubbing, sandblasting, etc., and then thoroughly cleaned from dust, metal surfaces are primed with EPOXYCOAT-AC anti-corrosion epoxy coating in one or two layers. EPOXYCOAT-AC is applied by roller, brush or spray. The second layer follows after the first has dried, but within 24 hours. 

Application-Consumption
Components A (resin) and B (hardener) are packaged in two separate containers, at the correct, fixed mixing ratio by weight.  At first, component A should be stirred. Then, the entire contents of component B is added to component A and the two components are mixed for about 3 minutes with a low-speed mixer (300 rpm). It is important to stir the mixture thoroughly near the walls and bottom of the container to achieve uniform dispersion of the hardener.