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ALSAN 601 liquid waterproofing: flexible and easy to use

13 Aug 2021
Case study

SOPREMA makes waterproofing easy. Take ALSAN 601, a polyurethane-based waterproofing resin that is ready to use, can be applied even during colder months and comes in handy-sized containers that are easy to move around, even in small areas. Read on to find out all about this interesting addition to the SOPREMA waterproofing portfolio.


ALSAN 601 is a single-component, seamless, elastic and flame-free waterproofing system that is compatible with numerous substrates including, timber, concrete and insulation. The product is rain proof after half an hour and can be overcoated in eight to nine hours under 24°C and 52% air humidity. Higher temperatures and air humidity will only increase its reaction speed. 

When a shorter curing time is required, ALSAN 601 Super Accelerator can be used, so small roofs can be finished in as little as a day. The product comes in two easy to use components, simply add the contents together and mix; there is no measuring of components required.

ALSAN 601 can be used in air temperatures ranging from 0°C to 30°C and with substrate temperatures from 0°C to 40°C. The products have a BBA 19/5684-certification indicating:

  • weathertightness (ALSAN 601 Roof Waterproofing Systems keep moisture from penetrating the building),
  • fire resistance (the systems can enable a roof to be unrestricted under the Building Regulations),
  • adhesion (they resist any likely wind suction acting on the roof),
  • resistance to mechanical damage (they support the limited foot traffic and loads associated with installation and maintenance),
  • durability (under normal service conditions, ALSAN 601 Roof Waterproofing Systems will provide a durable roof waterproofing with a service life in excess of 25 years according to the BBA certification).

ALSAN 601 is available in two RAL colours: 7001 (iron grey) and 7001 (silver grey). ALSAN 903 CP PIGMENTED is available for the topcoat.


Flexible and elastic, the ALSAN 601 waterproofing resin is adaptable to surfaces of all shapes and is suitable for varying applications, from new or existing flat or pitched roofs with limited access, balconies, terraces and podiums – even wetrooms and staircases. 

Before applying ALSAN 601 Roof Waterproofing Systems, make sure the substrate is solid, stable, and free from adhesion-reducing substances. Repair any cracks and fissures if needed. Adhesion tests should be carried out to test adhesion of certain types of substrate, this simple process can be performed quickly and effectively by trained operatives.

If the substrate needs a primer (bituminous felt, for instance, does not), opt for ALSAN 601 PU Primer or ALSAN 601 Humidity Primer A and B should a substrate contain moisture such as recently poured concrete. Apply one layer of ALSAN 601 by roller, brush, spreader or airless spraying, put ALSAN 601 Fleece 150 in as reinforcement and overcoat it with the top layer. ALSAN 601 Fleece 80 serves as a reinforcement over cracks, at upstands, for difficult details and other changes in the plane. Verge details can easily be carried out by using edge trims. 

SOPREMA supplies all the tools you need to install ALSAN 601 Roof Waterproofing Systems, from application rollers to buckets.


Our training centre regularly organises training courses on ALSAN 601 for applicators (contact our technical department for details), but our service does not end there. SOPREMA experts are always at hand to work out any calculations you may need. 

Moreover, partnering with us for both insulation and waterproofing means having a single point of warranty and contact if your project requires more than one product, such as a combination of a polyurethane roof coating system and a bitumen roof system.

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