Concrete Technology
DeepSeal Natural -
Product Specification|
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The Effects
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Unlike film-forming coatings such as those based on acrylic, polyurethane or epoxy resins, water repellents do not seal the pores at the surface of masonry.They form a very thin layer on the capillary pore walls. Water can no longer penetrate in liquid form into capillaries that have been
rendered water-repellent, since, as a polar liquid, it is unable to interact with a non-polar, hydrophobic surface. In other words, pores, which have been DeepSealed are therefore
hydrophobic and can no longer, bewetted bywater.
(a) a hydrophobic impregnation, (b) Filled pores,
and (c) a sealant film
The degree of wetting can be determined quantitatively as the contact angle, (fig. 4a,b).
Untreated surfaces of masonry building materials are wetted immediately by water, i.e., the drops of water spread out and are rapidly absorbed by the building material (fig. 4a). If the same building material is treated with impregnating agent, the drops of water retain their spherical shape and do
not penetrate into the substrate. The water is repelled in the form of beads (fig4b).
Fig 4a: Wetting of a hydrophilic porous surface
Fig. 4b: Water repellency of a hydrophobic porous
Water vapour can diffuse
Since the pores in DeepSeal hydrophobically treated masonry remain open, the building material retains its vapour permeability or “breath ability”. Accordingly, the passage of water vapour is impaired only slightly, if at all. This is of great importance, since moisture can diffuse to the outside without causing any damage, e.g., blistering and subsequent spalling, which frequently occurs with thick surface coatings.
Water under pressure
On the other hand, it is of course obvious that a water repellent treatment cannot render a building material resistant to groundwater or to prolonged driven rain, since the pores in the masonry are open. This can be a serious problem in cellars, and also with highly exposed facades. The larger the
pores in the building material the greater the problem. However, properly applied water repellents are
perfectly sufficient to render many standard building materials, such as sand-lime brick, clinker brick and concrete, resistant to wind driven rain.
Breathing new life into buildings
How “DeepSeal” functions
How can DeepSeal repel water so effectively and yet manage to remain permeable to water vapour? To use a simple analogy, they function rather like a leaf does in nature. Water is held at bay and runs off the surface, however the leaf can still exchange gases with the environment.
DeepSeal owes this property to its molecular structure. Chemically speaking, it falls midway between inorganic and organic compounds, with each molecule having an inorganic backbone, resembling quartz (SIO) in structure, to which are attached organic groups, denoted by (R).Thus the molecules have a highly specific structure.They align themselves on the building with their inorganic backbones (SIO) against the surface the organic groups (R) projecting outwards to present a barrier to moisture. The surface is hence rendered water repellent and very resistant to wetting. Nevertheless, the DeepSeal molecules do not clog the pores, therefore the surface retains its permeability to water vapour and “breathes”.
Therefore, treated buildings do not suffer from condensation damage. However the water repellency can be over come by water under pressure.
DeepSeal is available as a solvent based material as well as
an environmentally friendly water-based system.
DeepSeal Application
DeepSeal products are designed to be used on virtually any mineral surface so long as it contains a
calcium content, such as architectural paving shown below.
Service Life
Because the DeepSeal becomes part of the surface to which it is applied. It should give many years of service, however life expectancy will be dependent on the surface and environment in which it is placed.
Application
Is best with a low-pressure spray, by roller or brush, in a 2 coat system applied wet on wet, which means, the second coat is applied soon after the first coat. Apply only in temperatures between 5-30 Deg C. Deepseal is rain resistant in approximately 4 hours at 21 Deg C.
Coverage (m2/ltr/coat) Approximately
| Concrete |
4m2 – 6 m2 |
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Brickwork |
3m2 - 4m2 |
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Sandstone |
3m2 – 5m2 |
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Cement render |
3m2 – 5m2 |
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Exposed Aggregate |
4m2 – 7m2 |
Protective clothing, goggles, footwear and protective gloves should be worn when handling DeepSeal Products.
