Fescoseal A+B

Product description

The Fescoseal A+B two-component waterproofing compound is used in the waterproofing of floors and walls before ceramic tiles are installed. Fescoseal A+B is easy to apply, it dries rapidly, it is extremely flexible after drying, and it has excellent adhesive properties. The product is non-shrink and can withstand chlorides and frost stress. The waterproofing system has the cleanest M1 building material emission class. Certificate No. VTT-C-11838-16.


  •  Public wet areas
  •  Waterproofing of apartments
  •  Balconies and terraces

This product is suitable for air sealing renovations with Fescon sealing tapes VE-N and FS-N. Analysis conducted by Vahanen Rakennusfysiikka Oy. Results of the analysis available upon request.



The product is listed in the portal for building products that can be used in Nordic Swan Ecolabelled buildings.

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EAN code Product name Product number Package size
6416841769008 Fescoseal A 76900 10 kg
6416841769084 Fescoseal B 76908 10 kg


Instructions for use indoors
  • The base must be dry, solid and sturdy, and clean from substances reducing adhesion. The concrete and the levelling compound with cement binder are primed with Fescon Primer KP, diluted in a 1:3 ratio, before the waterproofing compound is applied. Use undiluted Fescon Primer KP for plaster of Paris bases. Before insulating, ensure that there will be no capillary water penetration behind the insulation. Any underfloor heating should be installed underneath the waterproofing. 
Mixture and use of the product 
  • Mix the liquid canister (component B) by turning it around (do not shake) and pour it into a clean mixing container. Then add the powder (component A) slowly while stirring constantly. Add the components in a ratio of 1:1 by weight (1 kg:1 kg) and stir until the product is completely homogeneous and free of lumps. 
  • The temperature of the room and the base must be +10 - +30 °C. The moisture of the concrete base must be below 95% RH. The working conditions must remain constant throughout the entire work. Apply the product with a paintbrush or a roller; it remains workable for around 45 minutes. 
  • Begin the waterproofing from the corners and joints. Spread the waterproofing compound in these locations and press a reinforcement into the compound with a trowel. In corners and, for example, over board joints, use Waterproofing Strip FS-N; in outside corners, use Outside Corner FS-U and in inside corners Inside Corner FS-S; for leadthroughs, use leadthrough flange FS-L (select the size according to the leadthrough); around the floor drain, use drain flange flexible KL-B 370x370 mm. Then spread the first waterproofing layer all around, also over the reinforcements. 
  • Allow the first layer to dry for around 90 minutes. Next, install the drain locking ring in place by cutting a hole into the drain flange that is 40 mm smaller than the diameter of the drain, fold and tighten the locking ring into place, apply a second layer of waterproofing compound all around, up to the locking ring around the drain. 
  • Allow the waterproofing compound to dry for around 4 hours before tiling. The dry film thickness of the waterproofing compound must be at least 0.8 mm throughout the waterproofed area.
Instructions for use outdoors
  • Fescoseal A+B can be used outdoors on concrete or cement-based surfaces. The tensile strength of the base must be at least 1 MPa. The base may be primed with water only in outdoor areas, and the base is dampened with water until it is darker in colour. In outdoor areas, the first waterproofing layer can be thinned with no more than 10% of water of the entire amount of the mixed product; use undiluted compound for the second application. Otherwise, follow the same instructions as for indoors. 
  • If necessary, use the same corner/leadthrough products as indoors. 
  • The dry film thickness of the waterproofing compound must be 2.0 mm in outdoor areas. 
After treatment
  • Protection must be given particular attention outdoors, and the waterproofed area must be protected from excessive water evaporation, excessive temperatures, draught, frost and rain. 
Other considerations
  • After the paste has begun to harden, it must not be thinned using water or component B. Neither should you add any other additives into the product. No levelling or adjustment may be done on top of a finished waterproofing coating.
Tool cleaning
  • The tools can be cleaned with water immediate after the use of the product
Waste handling

Storage and handling of waste. See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank

Technical information

Material usage

1.3 kg/0.8 mm layer

3.2 kg/2 mm layer

Colour dark brownish grey
Package size 10 kg + 10 kg

1 year in a warm location


1.14 g/cm3

Usage temperature

+10 - +30 oC

Workability time approx. 45 min
Drying time

Approx. 90 min between layers (+20 oC RH 50%)

Coatable tiles can be laid after approx. 4 h (+20 °C 50% RH) after the application of the last layer
Frost resistance frost-resistant
Film thickness 0.8 mm indoors, 2.0 mm outdoors
Method of application brush or roller
Transport Warm transport

The information is based on tests and practical experience. We cannot affect conditions at the work site so we cannot assume responsibility for the end result affected by local conditions.


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