ISOFLEX-PU 500 THIXO is a one-component, thixotropic, polyurethane, liquid waterproofing membrane for vertical, curved and sloping surfaces. ISOFLEX-PU 500 THIXO is based on elastomeric, hydrophobic polyurethane resins of excellent mechanical, chemical, thermal and weather resistance. Thanks to its thixotropy, it is easily applied to vertical, cured and sloping surfaces. The product has additionally the following properties:

• Forms a continuous, elastic, waterproof and vapor-permeable membrane, without seams or joints.
• Features excellent adhesion to various substrates, like concrete, cement mortars, metal, wood and most waterproofing membranes.
• Applicable even to irregular substrates.

ISOFLEX-PU 500 THIXO is suitable for waterproofing:

• Sloping roofs, flat roofs and balconies, as exposed waterproofing membrane.
• Gypsum and cement boards.
• Under tile layers in bathroom, kitchens, balconies and flat roofs, as long as quartz sand is 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 on the substrate must be primed locally and after 2-3 hours (depending the weather conditions) must be sealed with polyurethane sealants FLEX PU-30 S or FLEX PU-50 S. Concrete and other porous surfaces with moisture content < 4 %, should be treated with the primer PRIMER-PU 100, at a consumption of approx. 200 g/m2. Surfaces with moisture content > 4% should be primed with the special two component polyurethane primer PRIMER-PU 140, at a consumption of 100-250 g/m2.

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 epoxy 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 THIXO 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 THIXO, until it becomes homogeneous. Excessive stirring should be avoided though, in order to prevent air entrapment. 

a) Total waterproofing of the surface
ISOFLEX-PU 500 THIXO is applied by brush or roller in 2 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 8-24 hours, depending on the weather conditions. In case of dense, multiple cracks all over the surface, it is strongly recommended to fully reinforce ISOFLEX-PU 500 THIXO membrane with 100 cm wide polyester fleece strips (60 g/m2). These placed strips must overlap by 5-10 cm. In that case, 2-3 hours after priming, the first layer of ISOFLEX-PU 500 THIXO is applied, in order to cover the reinforcement (to a width of 100 cm), and while still fresh, a strip of polyester fleece is embedded. The same application process is followed in the remaining surface. Then, two extra layers of ISOFLEX-PU 500 THIXO are applied on the entire surface. 

b) Local waterproofing of cracks
In this case, the primer is applied on the substrate only along the cracks, to a width of 10-12 cm. Two-three hours after priming, the first ISOFLEX-PU 500 THIXO layer is applied and while still fresh, a 10 cm wide polyester fleece strip (60 g/m2) is embedded lengthwise. Two extra ISOFLEX-PU 500 THIXO layers are applied along the cracks, completely covering the reinforcement. 

c) Waterproofing under tiles
ISOFLEX-PU 500 THIXO is applied by brush or roller in 2 layers. ISOFLEX-PU 500 THIXO should be locally reinforced along joints and wall-floor junctions, by embedding a 10 cm wide polyester fleece strip (60 g/m2) on its first layer, while it is still fresh. Then, two extra ISOFLEX-PI 500 THIXO layers are applied along the cracks, completely covering the reinforcement. After applying the final layer and while this is still fresh, quartz sand must be broadcast. The quartz sand must be completely dry. Consumption of quartz sand: approx. 3 kg/m2. After 24 hours, any loose grains should be removed with a high suction vacuum cleaner.