What are Protective Coatings for Concrete Surfaces?
There are two categories of Protective Coatings:
1st, to protect and preserve structural concrete so that their characteristics in providing strengths and carrying the loads of a building are maintained. These characteristics might get otherwise lost through time or to physical and chemical reactions related to water absorption.
2nd, to protect concrete and its surfaces chosen to be visible components of a new building. If used outdoors, for example as facades, walls, floors for instance, protective coatings protect the concrete against the effects of inevitable weathering and aging effects. If concrete is used indoors as terrazzo or for countertops and similar, protective coatings are used to protect against aesthetic damage through daily wear and tear and against stains, helping to keep surfaces clean.
In HEBAU’s context, we focus on the 2nd group of protective coatings.
What types of Protective Coatings (sealers) for concrete are there?
There are two main groups of sealers or protective coatings: film forming and non-film forming. Because of low breathability film forming sealers have limitations when used for concrete surfaces that remain outdoors. As the wide majority of HEBAU customers make concrete that is designed and made for outdoors, HEBAU has been focusing on non-film forming protective coatings for years. HEBAU’s R&D on this aspect started in the 1980s therefore and still is an integral part of our daily working life.
There are many different Products and Suppliers. How does one differentiate the good from the bad?
That’s true, it’s become more and more difficult, even for us. However, a quick look at the product data sheet reveals very important information. When developing a new product, HEBAU takes the following properties into account:
- Sealers must allow water vapour permeability (breathability)
- Sealers must have a high Alkali Resistance
- Sealers must have high UV-Resistance
- Sealers must be water-based / Solvent-free
- Sealers must be durable
Suppliers of Protective Coatings should be able to address each of the above properties with a convincingly competent statement.
If this is not the case, be careful and consider contacting a HEBAU-Technician for a free consultation. We’ve come to realise over time, that the complexity of concrete is all too often grossly underestimated by suppliers of sealers.
What needs to be determined in advance in order to pick the “right” Sealer?
When choosing the most suitable product for you, please consider the following parameters:
- What kind of surface texture does your concrete have, e.g. a smooth finish or exposed aggregate, acid etched, sandblast…finish?
- Is the concrete meant for indoors or outdoors?
- Is the concrete surface for walls and facades or for floors?
- What are you protecting the concrete surface from, e.g. weathering effects, graffiti, from dirt and pollution, or from food stains…?
- Where, when, how are you able to apply the protective coating?
Try to identify these answers as best as you can. We are pretty sure that our HEBAU-Technicians will be asking you these very questions during your consultation.
How do HEBAU-Protective Coatings (Sealers) work?
Put simply, the principle of water repellency is achieved when changing the structure of the surface and the capillaries that lead there. The new surface structure then uses the surface tension of water droplets, and causes water droplets to simply roll off.
How long do HEBAU protective coatings last?
The short answer is, about 5-10 years on wall and façade surfaces.
The right answer is that, the effect of protective coatings depends on the type of active ingredients and the concentration inside the protective coating, but it is also related to the absorbency of the surface, method and quantity of application, qualification/motivation/clear headedness… of the person(s) carrying out the work, use of appropriate tools, wind direction and spraying distance, quality control of procedures, concrete-mix design, colour of concrete, finishing, age of concrete, type of cement, vibration procedures, density of the concrete, uniformity of spread of cement, sand and aggregates throughout the surface, building’s position and exposure to sun (UV-Index) and main wind direction, local rainfall frequency, height of the building, wind speed, and other specific local climate parameters…
Please note: Because of all of the above, a reliable supplier does not and would not give a general guarantee on the durability of a certain sealer in years without knowing the details of the project. Should you receive such promises, please be warned, your alarm bells should go off.
How much do HEBAU protective coatings cost?
The short answer is, next to nothing by comparison to the total investment cost of the building.
The right answer is that, the costs depend on the price of the protective coatings, the required amount, which depends on the absorbency of the concrete surface, the concrete finishing, concrete-mix design, vibration procedures, density and age of concrete, application method…
Are the HEBAU protective coatings visible? What is the optical effect?
Well, it depends and you have options.
HEBAU offers several protective coatings, from totally transparent (matt finish) to colour enhancing (wet-look), shiny to pigmented. Especially among architects we notice that the preference tends to be for an “invisible” sealer and this decision is often made early on in the process without knowing other options. Sometimes however, a protective coating with a certain optical effect might be worthwhile testing and seeing, because a concrete surface might look more “valuable” then. By running a few tests, and comparing the results allow you to select the ‘better’ option for you.
Invisible (matt finish): COLORTEC® Max & COLORTEC® finish
Colour enhancing (wet-look): COLORFRESH® effect
Colour enhancing (wet-look) & silky sheen: COLORFRESH® intensiv
How to make a test-surface?
- The best thing to do, is to discuss all requirements well in advance – in particular onto what type of concrete surface the protective coating will be applied, i.e. smooth or with a finishing such as exposed aggregate surface, acid-etched, structured…, since the results and quantities per square meter vary depending on type and time of application.
- Create a suitable test surface, apply the protective coating in the same way you have chosen for the application later when starting the project, expose the surface to sun, rain, wind… (do not keep it in the laboratory) and consider sufficient observation time to draw the right conclusions.
- Make sure you have read and understood the technical data sheet before starting your tests, in order to avoid making mistakes.
- Always run a ‚control test’ without a protective coating for reference.
- Allow decision makers to inspect and give their verdict.