When it comes to resealing stamped concrete it is very important to make sure the new sealer is compatible with the old sealer. Mixing sealers that aren’t compatible could result in coating failure.
Stamped concrete is typically sealed with an water based acrylic or a solvent based acrylic. A good rule of thumb is water based acrylics need to be resealed with water based acrylics, and solvent based acrylics need to be resealed with solvent based acrylics. If you put a water based acrylic over a solvent based acrylic, or a solvent based acrylic over a water based acrylic, the solvents will most likely attack the water based formula and result in coating failure.
If you have a water based acrylic down on your stamped concrete and are re-coating with a water based acrylic, you may need to lightly screen scuff the surface to allow for adhesion. If there isn’t much left of the water based acrylic, this step may not be required. A test area is always suggested.
If you have a solvent based acrylic down on your stamped concrete and are re-coating with a solvent based acrylic sealer, you simply apply the new sealer to a clean and dry surface.
Here are a few frequently asked questions about resealing stamped concrete:
- If I have a water based acrylic sealer down now, can I switch to a solvent based? You can, but you need to make sure that all of the old acrylic sealer has been removed with a coatings stripper first.
- If I have a solvent based acrylic sealer down now, can I switch to a water based? you can, but you need to make sure that all of the old acrylic sealer has been completely removed with either Xylene or a coatings stripper.
- I don’t see any old sealer left on the surface, can I use whatever I want? No. Just because you can’t see the old acrylic, doesn’t mean that there isn’t still resin in the pores. If it has been 3-5 years, check with the manufacturer of the new acrylic sealer first.
- Do I need to re-coat with 1 coat or 2 coats? That will depend on how much old sealer is left, and how glossy you want the stamped concrete to look like once sealed. Two coats is always suggested for a more even application.
- Will resealing bring out any dull and faded coloring? If a solvent based acrylic sealer is used, then yes, but if a water based acrylic sealer is used, then no. Most water based acrylic sealers don’t contain the resins used to darken the concrete surface in order to make it look wet.
- Do I need to acid etch my stamped concrete before sealing? No, you should never acid etch an old sealer before applying a new sealer. Typically a light pressure washing is fine, and spot treat deep stains.
- Do I have to re-coat with the same product? No. As long as you stay consistent with re-coating water based products with water based, and solvent based with solvent, there usually aren’t issues. If you have questions, it is always best to contact the manufacturer of the new product you are considering.
If you used a penetrating water repellent sealer and did not use an acrylic, most solvent based acrylic sealers can be applied to the surface after first checking with the manufacturer.
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