How to get rid of discolouration on a concrete surface?

How to get rid of discolouration on a concrete surface? Especially in the hot season, the phenolic resin
coating is exposed to intense sunlight, which can leave a brown colour on the concrete surface. This
undesirable problem can be minimized or even prevented.
Have you seen the discolouration? This brown — sometimes curved — discoloration that appears on the
concrete surface when the formwork is removed? The bad news: when using phenolic resin plywood,
regardless of the supplier, the discoloration is very likely to occur because the properties of the plywood
are resistant to the ultraviolet radiation. The good news: you can reduce the damage and even prevent it if
you carry out the following simple steps.
Situation 1 | You use phenolic resin plywood and want to reduce discoloration

  1. Minimize exposure of the phenolic resin coating to UV radiation
    Protect plywood from intense sunlight, e.g. by storing it vertically with concrete surfaces they should be in
    contact with each other or you can cover them.
  2. Watch out for residue
    Keep the formwork clean before pouring the concrete. Before use, remove any dirt, rust, fingerprints from
    the plywood surface.
  3. Adjust the construction cycle
    You have to loosen the tie bars in each panel and remove them from the concrete immediately.
    Otherwise, it is likely that the formwork panels may move away from the concrete surface in some areas
    while continue to be attached to it in other areas. This can create a gap between the hardened concrete
    and the formwork where condensate water, dirt, concrete or release agent residues and / or dissolved
    phenolic resin will accumulate there.
    Situation 2 | You used phenolic resin plywood and want to remove discolouration

In some cases, discolouration of concrete surfaces can be effectively removed with a mild acid such as
softly concentrated formic acid. An alternative is the use of professional cleaning agents (however, it is
recommended to consult a concrete or stone cleaning company beforehand). Mechanical removal tools
are also an option, e.g. You can apply the process of grinding and patching. Any removal steps should be
first carried out on the area dedicated for testing, as the methods may get negative result instead of
improving the surface condition. They can even deteriorate the appearance of the concrete surface or
highlight defects on the surfaces.
Situation 3 | You want to prevent discolouration altogether
The best way to prevent discoloration caused by phenolic resin is, of course, to use alternative
thermoplastic plywood.

Discolouration on a concrete surface – Betoff-bio

How to get rid of discolouration on a concrete surface?


There is no shortage of chemical products on the construction market that will remove dirt from concrete.
The problem is that such chemical may affect negatively the environment, human and animal health. That
is why Innovatech has developed an innovative formula that can clean concrete and keep the environment
safe. Betoff-Bio is a fluid based on an endemic plant that removes all dirt from concrete surfaces and
more. Cleaning companies use Betoff-Bio to clean the facade, all kinds of stone, and also to clean the
joints. Betoff-Bio is the only such liquid on the market, and its composition and mixing technology are a
strict secret. This liquid can also remove cement and lime stains from windows, zinc, plastic surfaces and
even rubber elements.

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