Bentonite cord for foundation waterproofing: where to use and what size to choose

Foundation
waterproofing is an important condition for the long-term durability of a building. Even a strong concrete
structure can allow water to penetrate through construction and cold joints, joints between individual elements,
or areas where utility services pass through.

For
sealing such areas, bentonite waterproofing cord is used.
When it comes into contact with water, it swells and seals the space around itself, creating
an additional barrier against moisture penetration.

Where Bentonite Cord Is Used in Foundations

Bentonite
cord is used for localized sealing of the most vulnerable areas of concrete
structures.

Main
applications include:

• construction and cold joints in concrete;
• joints between the foundation slab and walls;
• connections between basement walls and the foundation slab;
• joints between concrete and reinforced concrete structures;
• areas where pipes and utility services pass through;
• construction openings after formwork removal;
• underground parts of buildings that are in contact with groundwater.

Thus,
bentonite cord is not used for continuous waterproofing of the foundation
surface. Instead, it protects joints, connections and individual structural areas through
which water may penetrate.

Bentonite Cord for Foundation Slabs

The material is
particularly relevant when a foundation slab is concreted in stages.

A construction
joint forms between already hardened concrete and newly poured concrete. If it is not
sealed, it can become a path for water to enter the underground part of the
building.

Bentonite
cord is installed along the future joint and fixed before the next section of
concrete is poured. When it comes into contact with water, it swells and seals
the joint area.

The cord is
also used at the connection between the foundation slab and the vertical wall,
where a construction joint often forms.

Important:
bentonite cord is an element of a waterproofing system and does not replace
comprehensive foundation protection.

How to Choose the Size of Bentonite Cord

The choice of
cross-section depends on the type of structure, joint dimensions, thickness of the concrete
element and operating conditions.

SANSTORE offers
rectangular profiles and a round D-22 cord.

Bentonite Cord 5×20 mm

A compact
rectangular profile that is convenient for sealing pipe penetrations
and other utility service penetrations.

Bentonite Cord 10×20 mm

One of the
standard sizes used for sealing construction and cold joints in concrete
structures.

Bentonite Cord 15×25 mm

Used for
sealing joints in foundations, foundation slabs, and other concrete and
reinforced concrete structures.

Bentonite Cord 20×30 mm

A larger
profile for massive concrete structures, foundation slabs, and other
critical underground structures.

Round Bentonite Cord D-22

Its area of
application differs from that of rectangular profiles. It is used for
sealing construction openings, particularly openings left after the removal
of formwork tie elements.

Bentonite Cord for Basement Waterproofing

When
constructing basements, bentonite cord is used in areas where concreting
is carried out in separate stages:

• at the joint between the foundation slab and wall;
• in horizontal and vertical construction joints;
• around utility service penetrations;
• in construction openings.

To protect the
underground part of a building from groundwater, the cord should be used
together with other elements of the waterproofing system.

Sealing Pipe Penetrations in the Foundation

Another area
of application is where utility services pass through the foundation.

The area around
a pipe can become a path for water penetration even when there are no cracks in
the concrete. For such structural areas, a bentonite cord with the appropriate
cross-section can be used, in particular 5×20 mm.

For more
information about this technology, read the article “Sealing Utility and Pipe
Penetrations with Bentonite Cord.”

What to Consider Before Purchasing

Before
choosing a bentonite cord, determine:

1. the type of concrete structure;
2. the location of the joint or connection;
3. the thickness of the concrete element;
4. operating conditions and possible exposure to water;
5. the required cord cross-section.

A larger
profile is not always better. The size should correspond to the specific structural
area and project requirements.

SANSTORE Bentonite Cord

At SANSTORE,
you can buy bentonite waterproofing cord in various standard sizes:

• 5×20 mm;
• 10×20 mm;
• 15×25 mm;
• 20×30 mm;
• D-22 mm.

The material
is suitable for sealing construction and cold joints, foundation slabs, joints
between concrete structures, utility service penetrations and construction
openings.

If you are not
sure which bentonite cord to choose for a foundation, provide the manager
with information about the type of structure, concrete thickness, joint
location and operating conditions — this will help select the appropriate
size.

Conclusion

Bentonite
cord for foundation waterproofing is used to protect construction and cold joints,
connections between foundation slabs and walls, utility service penetrations,
and construction openings.

Different
cross-sections are used for different applications, from the compact 5×20 mm
profile to the 20×30 mm profile, while the round D-22 mm cord has a
specific area of application.

A properly
selected and installed bentonite cord helps improve the watertightness of
concrete structures and protect underground premises from water penetration.