Preventing Moisture in Decorative Concrete
If you are installing decorative concrete, beware of moisture's impact. It has the potential to ruin your new concrete as only a certain amount of it evaporates. When excess moisture is left in your decorative concrete, it could completely tarnish the design.
Before you install your decorative concrete, you should take multiple variables into account. Things like sealer combination, specific stains, and moisture have the potential to make or break your new surface. Be extremely careful to maintain the proper amount of moisture when applying both the stain and the sealer.
Excess moisture can come from the amount of water that is used when mixing the concrete. It can also come from an external source like water that is already present within the ground. This can prove to be especially troublesome if you don't have a vapor retarder. It's not just pooled water that can interfere with sealer and stain. It's also water that is in the process of evaporation as well.
The extent of the moisture's damage will be determined by how much extra moisture there is and the type of sealer or stain used for the project. Each will have a different impact on the appearance of the sealer and stain. If you apply the stain or sealer before the concrete has had a chance to dry, moisture may rise up the slab and bring salts to the surface, creating an ugly efflorescence. This will appear as a white powder. If it is trapped beneath sealer and some stains, the concrete will have an ugly white hue.
Excess moisture can cause the acids and salts in green or blue stains to turn very dark. Sometimes they become black in color. This is likely caused by the presence of fungus or the oxidation that results from the abnormally high amount of moisture. Moisture can also cause efflorescing salts to slow stain penetration and negatively affect the color process of the concrete’s stain coloring.
Other imperfections caused by an improper amount of moisture include peeling and flaking when the concrete can't bond with the stain due to the watery consistency. When moisture can't evaporate, it can result in dark spots that will tarnish your new concrete. If there's too much moisture and it can't escape the mixture, your decorative concrete could end up with blistering and even bubbling.