Impermax Primer (Porosity Sealer Flex)

Impermax Primer (Porosity Sealer Flex)
Impermax Primer (Porosity Sealer Flex)
  • Primer for Impermax
  • For EPDM, PVC and Bitumen
  • Easy in use

Porosity Sealer Flex is a 1-component primer specially developed for Impermax roofing. The flexible aromatic, moisture-curing polyurethane resin improves adhesion on EPDM and PVC roofs. In addition, this primer prevents 'bleeding' of bitumen on white roofs. It is an excellent polyurethane primer for repainting old bituminous layers with polyurethane waterproofing systems such as Impermax B1K (black) and Impermax LY (white).

Benefits of Impermax Primer

  • Easy to use.
  • Suitable as primer for Impermax roofing.
  • Improves adhesion on EPDM and PVC roofs.
  • Prevents 'bleeding' of bitumen on white roofs.

When do you use Impermax Primer?

You can easily use this primer for EPDM, PVC and bituminous roofs:

EPDM & PVC roofs

To increase adhesion on this type of roof, we recommend applying Porosity Sealer Flex before covering the roof with Impermax liquid roofing.

Bituminous roofs

Are you going to work on a bitumen roof? Then a primer is not always necessary, especially if you use black Impermax B1K, because this hybrid system already contains bitumen and polyurethane. With white roofs, however, the bitumen may stain on the white Impermax coating, because Impermax dissolves part of the old coating. You can prevent this by first treating the roof with this primer or by applying two layers of Impermax LY. The first layer then serves as a primer layer.

Instructions for use

Impermax Primer (Porosity Sealer Flex) is easy to apply to the surface. Make sure the surface is dry and dust-free for optimal adhesion. Also repair possible roof blisters before applying the primer. Process at a minimum temperature of 0°C and a maximum temperature of 30°C. Higher temperatures may cause blistering under the primer due to the rapid evaporation of the solvent.

Application                                                                                                                                                                                                                                                                                                             Apply the primer with a roller, brush or airless spray equipment. We recommend using the entire contents of the can. If you have any material left over after use, close the container tightly and store it carefully. You can apply Porosity Sealer Flex without any problems. Would you rather dilute it (up to 25%)? Then only use Rayston PU Solvent for this and no other thinners.                                          

The cure time of the primer strongly depends on the environmental conditions. The higher the temperature and humidity, the faster Porosity Sealer Flex cures. Usually the primer is hand-dry after 5 hours at 25°C and 50% humidity. If the primer is hand-dry, you may apply a second coat up to 48 hours after drying. It is important that all solvents are dissolved before applying a second layer. This will prevent air bubbles from forming under the surface of the primer.

Now allow to cure again before continuing with the application of Impermax B1K or Impermax LY.


Contents: 4 kg, 20 kg
Colour: transparent to light yellow
Consumption: 100-300 gr/m2
Processing time: 2 hours
Curing time: 5 hours
Processing temperature: 0-30°C
VOC content: 69%
VOC content: 330 g/l
Viscosity: 350 mPa.s (20°C)
Hardness: Shore 65A (ISO 868)
Maximum elongation:
Temperature resistance: 80°C
Shelf life: until 12 months after production date

We have a number of recommendations for working safely with polymers. At Polyestershoppen you will not only find the polymers themselves, but you can also purchase all the protective equipment you need from us. If you have any doubts or questions, please contact our customer service. We can give you advice on how to work safely with polymers.

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