Radon tight and root resistant waterproofing membrane

  • Radon tight and Root resistant
  • Dual waterproof protection – A 3D-PE honeycomb liner and a self-healing, swelling bentonite layer
  • May be installed in all weather conditions
  • Suitable even in tough conditions due to flowing groundwater
  • Environmentally friendly alternative



As a first line of defense, a great waterproof membrane will stop water coming into contact with your below ground structure. This is important because concrete will invariably crack, be it from settlement, unequal static forces or during curing. Needless to say, water ingress can cause extensive harm to your structure and internal environments and if there are ground gases, they too must be prevented from entering through the sub-structure.

Cemtobent® CS is a highly durable waterproofing membrane that will effectively stop pressurized ground water and radon from penetrating your structure. The membrane will also protect against roots and seal small cracks caused by settlement, concrete shrinkage or seismic activity

Application – Where to use Cemtobent® CS

Cemtobent® CS is for any application where below grade reinforced concrete structures must be protected against groundwater and radon gas.

Main areas of application:

  • Sealing and protection of reinforced concrete in below ground structures and tunnels. Both vertical and horizontal applications.
  • Floor slabs and exterior concrete walls
  • Pressurized and non-pressurized water
  • Suitable for use in flowing groundwater conditions.
  • Wherever radon gas, and/or roots may be a potential

Technology – How does Cemtobent® CS work?

The sealing process of the bentonite lining system is activated immediately by penetrating water causing a controlled swelling of the bentonite clay within the matrix, forming a dense, impermeable waterproofing membrane.

If the primary sealing (3D-PE-Sheet) is damaged, the exposed bentonite reacts with the incoming water creating an extremely tight and strong, gel-like film, which seals the concrete structure (secondary sealing) and stops any water circulation between the membrane and the concrete.

Even shrinkage cracks are reliably sealed and overbridged.

Installation – Benefits

  • Quick and easy to install without complicated welding equipment
  • May be pre-applied or post-applied
  • Can be installed in all-weather condition or temperature
  • For installation instructions, please refer to Cemtobent® product brochure or contact your local Cemproof technical support


  • CE-Marking Root resistance and radon tightness
  • Clearance Certificate of environmental soundness


  • 1,80×30 m (Art.nr: 20-100)
  • 3,60×30 m (Art.nr: 20-101)
  • 1,20×30 m (Art.nr: 20-102)
  • Approx. 5500 g/m2
Form of delivery
  • 1,80×30 m; Roll in black foil; Ø ca. 60 cm; approx. 300 kg/roll(Art.nr: 20-100)
  • 3,60×30 m; Roll in black foil; Ø ca. 60 cm; approx. 600 kg/roll(Art.nr: 20-101)
  • 1,20×30 m; Roll in black foil; Ø ca. 60 cm; approx. 200 kg/roll(Art.nr: 20-102)
  • Cemtobent® CS should be stored off the ground in dry conditions. Unlimited shelf-life.
Minimum concrete cover
  • N/A
  • Minimum 150 mm
Lifetime expectancy
  • Life of the structure
Grade of waterproofing protection
  • Grade 1, Grade 2, Grade 3 as British Standard 8102:2009
Type of waterproofing system
  • Type A BS8102:2009


  • Product data sheet
  • Product brochure


  • Mercure Hotel Budweis / CZ
  • Seewinkeltherme Frauenkirchen / AT
  • Pragsattel Stuttgart / GER


Superior waterproofing technology

Cemtobent® CS is the “new school” of Bentonite liners and not to be confused with basic Bentonite liners on the market. This high-tech composite membrane is designed to handle the most demanding challenges your below grade structure might face.

Secures structural integrity – For life

Cemtobent® features two separate water-reactive layers that independently will swell, stopping incoming water and also sealing smaller cracks caused by ground-settlement, concrete shrinkage or seismic activity.

Less labor-intensive

Quick and easy to install without complicated welding equipment

May be pre-applied or post-applied

Can be installed in all-weather conditions and temperatures

Main benefits of CEMTOBENT® CS

Protects against pressurized groundwater (5 bar/50 m)
Root resistant and certified as radon-tight
Seals small cracks caused by ground settlement, concrete shrinkage or seismic activity
Rain protected / all-weather installation



Complete your design with one or several of the following products to achieve a fail-safe combination waterproofing system:

  • QUELLMAX® PLUS – Swellable joint waterstop tape with rain protection
    • Dual protection through both swelling (>500%) and additional mineralization that heals concrete through formation of free lime.
    • Optimal for structures that will be subjected to high water pressure (tested up to 7 bar/70m) and variable water tables.
    • The infinitely reversible swelling/shrinkage secures the integrity of your structure throughout it’s expected service life
    • The protective coating of Quellmax® Plus protects against premature swelling due to rain or general site water
    • Quellmax® is installed on the “Waterside” and Predimax® on the “dry side”
  • PREDIMAX® – Multiple Injection System for construction joint sealing
    • “Future-proof” your structure with this built-in multiple injection system, allowing for initial, scheduled, or remedial sealing of Joints
    • Easy to install
    • A unique patented design prevents unwanted fresh concrete paste to enter the system.
    • Predimax® is installed on the “dry side” and Quellmax® on the “waterside”

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