Waterproofing compound WS

Product description

Fescon Waterproofing Compound WS is a Fast-drying, single-component indoor waterproofing compound that can be rolled or sprayed. Suitable for the waterproofing of floors and walls.  


  • Consumption about 0.7 l/m2 on walls and floors
  • Sufficient dry membrane thickness easily with two treatments
  • Extremely elastic
  • Can also be sprayed
  • M1 and EC1 rated
  • Certificate No. C-12511-18


  • Waterproofing of indoor walls and floors to be tiled.
  • For the treatment of interior concrete element seams in apartment and public buildings, to prevent cracks in the completed interior surface
  • The substrate can be concrete, lightweight concrete, a cement-based filler or building board suitable for wet rooms
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EAN code Product name Product number Package size
6416841769091 Waterproofing compound WS 76909 3 l
6416841769121 Waterproofing compound WS 76912 15 l


  • The substrate can be concrete, lightweight concrete, a cement-based filler or building board suitable for wet rooms
  • The substrate must be clean, solid, dust-free and vacuum-cleaned. The substrate must be solid and immobile.
  • Loose layers, cement paste and any other impurities have been removed mechanically to ensure adhesion between the product and the substrate.
  • The substrate temperature is more than +10 °C and the relative humidity less than 90%.
  • Underfloor heating must be turned off two days before waterproofing.
  • Uneven floors are levelled with Fescon floor levelling plasters, and the walls with Fescon Levelling compound for wet areas WTT
  • Priming is done with Fescon Primer KP, following the instructions in the product card. 
  • Concrete substrates and cement-based filler substrates: 1 part Fescon Primer KP, 3 parts water.
  • Substrates that do not tolerate moisture, such as gypsum-based building boards: Not to be thinned. 
  • Fescon Primer KP is spread thinly with a brush. Fescon Primer KP must not be applied so much that it creates puddles. 
  • Two treatments for highly absorbent substrates (such as concrete floors cast on site).  
  • Fescon Primer KP must be dry before Waterproofing compound WS is applied, requiring 1–4 hours, depending on the conditions.
Mixing and application of the product
  • Use the following accessories with Waterproofing compound WS: Drain flange KL-B, Waterproofing accessories (FS and VE series) and Waterproofing strip 0.15 x 25 m fibre.
  • Waterproofing compound WS is always applied twice. 
  • Waterproofing compound WS is mixed before use. 
  • Start the waterproofing with the walls. Spread Waterproofing compound WS into the corners, where two elements meet and into through holes. Attach reinforcements to these locations with a roller or brush. Ensure that the reinforcements are completely covered by Waterproofing compound WS. 
  • Apply the first layer of Waterproofing compound WS across the entire wall area to be waterproofed. The second layer may be applied about 2–3 hours later. Waterproofing compound WS changes colour as it dries. The surfaces must be dry before the next layer.
  • Begin waterproofing the floor. Spread Waterproofing compound WS into the wall and floor corners, where two elements meet. Attach reinforcements to these locations with a roller or brush. Ensure that the reinforcements are completely covered by Waterproofing compound WS.
  • Install the Drain flange KL-B onto dry primer. The drain flange is attached to the dry primer surface by pressing the adhesive down around the drain. Apply Waterproofing compound WS all over Drain flange KL-B. There is no waterproofing material under the flange.
  • Apply the first layer of the waterproofing compound across the entire floor area to be waterproofed. Allow the first layer to dry for about 2–3 hours before installing the floor drain clamping ring, and applying the second layer. 
  • Install the clamping ring. Start by cutting out a whole in the middle of the floor drain, 40 mm smaller than the floor drain diameter, then fold and tighten Drain flange KL-B using the clamping ring against the inside of the floor drain by applying steady pressure. 
  • Apply Waterproofing compound WS on the entire area to be waterproofed for a second time. Apply the compound also between the clamping ring and the drain flange from the top. Waterproofing is not applied to the inside of the floor drain.
  • Tiling can be started about 5 hours after the last layer of waterproofing compound has been applied. 
  • Use Fescon tile adhesive plaster VSL, ILL, SS2 or SSL Lite, depending on the tile and target. 
  • If any waterproofing compound is visible between the clamping ring and floor drain cover, cover it over with adhesive plaster to protect it. 
  • Tiles can be grouted with Fescon Tile seaming plaster SML and sanitary silicone, following the instructions for the adhesive plaster.
Other considerations
  • Waterproofing is carried out in accordance with RT cards and RIL guidelines. 
  • The drying times in the product card apply to +20 °C, relative humidity 50%. Low temperature or high humidity in the work area extend the drying period.  
  • The product will dry enough to walk on within about 2–3 hours. Avoid walking on a surface that has been waterproofed, because the surface may be broken. You may walk and work on a waterproofed floor only wearing clean safety footwear.   
  • Waterproofing compound WS is not suited for outdoor use, such as balconies. Similarly, the product cannot be used is locations in which the waterproofed spaces may freeze, such as outdoor saunas without continuous heating. For such locations, use Fescon Fescoseal A+B two-component waterproofing compound. 
  • Waterproofing compound WS is not suitable for spaces continuously exposed to water, such as swimming pools
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

walls and floor: approx. 0.7 l/m2  (min. 1,0 kg/m2)

Colour Light blue, darkens when drying
Package size 3 l / 4,5 kg and 15 l / 22,5 kg. Packed in a plastic container.

For 12 months from the manufacturing date shown on the package, store in a warm place. The product must not freeze.


1 l = 1.5 kg

Usage temperature

+10°C...25°C (platform and internal temperature) 

Drying time

About 2–3 hours first treatment. After second treatment, about 5 hours before installing tiles (+20 °C, relative humidity 50%).

Coatable Tiles may be installed after a second treatment, after about 5 hours.
Frost resistance not frost resistant
Film thickness Min. 0,5 mm (both walls and floors)
Method of application brush, roller or spray
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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