A proper bonding between concrete and concrete sealer is vital to ensure proper strength and adhesion between bonded surfaces. If not executed properly, it can result in surface separation and even sealer failure in severe cases. Follow manufacturer’s instructions on surface preparation in order to attain a level of perfection which prevents failure in the intermolecular bonds between concrete surface and sealer. Furthermore, if you adhere to the following instructions, and with a little bit of dedication, your achievement will be regarded as master craftsmanship by a pro.

Surface Preparation

First and foremost, remove any dirt and other contaminants from the surface to be sealed. Use a good blower or brush/broom to remove any dust. Wash it down with soap and water, and then again with clean water, so that no soap residue remains. Any residue is fatal for the process, as will be explained later. Be sure to let the sealer surface dry properly before applying concrete sealer. Be sure that no excess release-powders, stain residues, soap residue or efflorescence remain, as these are the main culprits behind a ruined concrete sealing. Stain residues, soap residues and efflorescence have high pH value that may result in whitening or formation of soft spots on the sealer surface, an indication of sealer pH imbalance. Proper neutralization and cold water rinse will ensure that no harmful residue is left between the sealer and concrete surface.

Porosity Check

You need to know how the surface ‘absorbs’ water in order to determine if it is porous enough to absorb the concrete sealer. Low absorption of the sealer may result in low durability of the whole set-up. Run a simple water test to check the porosity of the concrete surface. For these tests, refer to various surface absorption tests and permeability checks. These tests are all about checking the liquid absorption rate of the surface. Water penetrates a surface by osmosis or diffusion. These tests are relatively simple, but to make it simpler, take the help of a digital machine available in the market.

Hand toweled concrete surfaces are generally porous to the extent that they absorb one part of sealer with low solids, usually under 30%. A machine toweled surface, on the other hand, usually requires additional steps to make the surface open to the same type of concrete sealer.

In order to open up the surface, use light sanding or acid etching. Take help of various sanding machines, or polishers available locally. They grind the surface to a smooth finish, besides allowing the entire dust residue to be removed. You may use a commercial polishing compound in the final step to clean any residue from the process itself, leaving you with a dirt retardant surface.

While etching with acid, take extra precaution as you will be dealing with potentially hazardous materials. Avoid any contact of the acid with your skin and eyes. Also work in a properly ventillated area. Please also note that in case of higher solid sealers, like more than 45%, it is recommended that you first open up the surface, or dilute the first coat of concrete sealer. The entire process is relatively easy and can be completed in more or less a day. Just keep it cool and work with a little dedication.