What Happens When the Concrete Already Exists?
Integral admixtures are excellent for new construction, but many waterproofing problems occur in buildings that were completed years ago.
A basement may begin leaking.
A retaining wall may develop damp patches.
Water may penetrate a lift pit.
A tank may begin losing or admitting water.
This is where surface-applied crystalline waterproofing systems such as Xypex Concentrate can become relevant.
What Is Xypex Concentrate?
Xypex Concentrate is a cementitious crystalline waterproofing treatment applied to prepared concrete surfaces.
According to Xypex technical literature, the material contains Portland cement, graded sand and active proprietary chemicals. It is applied to a pre-saturated concrete surface, after which the active chemicals diffuse into the substrate and react with moisture and cement hydration products.
The resulting crystalline formation develops within pores and capillary tracts in the concrete.
Typical Applications
Xypex recommends Concentrate for structures including:
- reservoirs;
- foundations;
- underground vaults;
- tunnels;
- parking structures;
- swimming pools;
- treatment facilities;
- secondary containment structures; and
- precast concrete.
For appropriate projects, this makes it relevant to many remedial waterproofing situations encountered in Uganda.
Positive and Negative Side Waterproofing
One of the major challenges in existing buildings is that the water-facing side of a concrete element may no longer be accessible.
For example, the outside face of a basement wall may already be buried.
Excavating around the entire building may be impractical.
Crystalline systems can therefore be useful in applications where waterproofing must be approached from the accessible side of the concrete.
However, the final treatment should still be based on the specific structure, condition and pressure involved.
Preparation Cannot Be Ignored
The waterproofing performance depends heavily on preparation.
Typical work may include:
- removal of paint or coatings;
- exposing sound concrete;
- removing laitance;
- cleaning contamination;
- repairing honeycombs;
- opening and treating cracks;
- repairing defective joints;
- treating active leakage; and
- pre-saturating the concrete.
Xypex publishes separate installation procedures for coating applications, below-grade negative-side waterproofing and repair of cracks and faulty construction joints.
At Tetrabuild, we regard preparation as part of the waterproofing system itself rather than a minor preliminary activity.
