Sealing Old Stamped Concrete Tutorial

Sealing Old Stamped Concrete

Re-sealing old stamped concrete doesn't have to be a difficult and expensive experience if time is taken to make sure that the correct cleaning and preparation procedures are done. It is also important to know what concrete sealer was used originally. The most common sealer used on stamp concrete in Australia is solvent based acrylics or water based acrylics (film forming sealers), this tutorial is based on re-sealing solvent based acrylics. Additional steps are required when re-sealing polyurethanes and penetrating sealers.

In most commercial or high traffic areas polyurethanes are used for sealing. Polyurethanes are thicker and give you higher high abrasion and chemical resistance than your standard cheap acrylics . If polyurethanes have been used the only way to get adhesion is through abrasion(sanding).

PREPARATION AND CLEANING

1st Step  - Pressure Clean

Use a pressure cleaner with at least 3000PSI. Clean down the area to be sealed make sure you don't miss any spots.


!Tip -. Try and keep the nozzle the same distance from the surface. Do little areas at a time quickly go back over the area in the opposite direction.

2nd Step - Time to clean and degrease your concrete

Just because you have used a pressure cleaner and the concrete looks like new again doesn't mean it's clean enough to start sealing. For areas where the pre-existing sealer that has worn away could have allowed oil and grease to socked into the the concrete's substrate. Cars and machinery are a big problems when it comes to this but the man's best friend (the family pet) causes plenty oily patches when laying down out on the back patio.

A all in one commercial grade heavy duty cleaner will normally be suffice, use a coarse bristle broom and give it a good scrub. For the stubborn areas use a heavy duty degreaser these you find for about $10.00 from your local auto shop or hardware or try a bit of kitty litter see the article on:
How to Clean Oil Off a Concrete Floor

Ensure you thoroughly clean down the area and make sure there is no residue left from the cleaner or degreaser. If you come across any flaking sealer this will have to be removed before you continue as it will cause de-lamination later down the track. Allow to thoroughly dry a moisture will cause sealer whiteness, a normal summers day is normally enough. If in doubt do a moisture test: Moisture Test - How to do my own moisture test on my concrete.

3rd Step - Promoting adhesion by solvent washing

There are two ways to get adhesion between coatings;

• Key Etch: Top coat finds little hook like shapes in micro scratches which holds the two coating together
• Re-melt: Using solvents like xylene or adhesion promoters to remelt and soften when applying new coats will form a bond with old coats.

Using a solvent resistant broom, brush out the solvent or adhesion promoter over the area required to be sealed.

APPLICATION

4th Step - Apply the Sealer

Using a lint-free large nap roller or solvent resistant broom to apply your sealer. Depending on how deep your stamp pattern is, it might be easier to use a solvent resistant broom to reach in to all those lower spots, if it is not too deep you can use a large nap roller sometimes can be quicker. Make sure you don't miss any spots or leave pools of sealer in the lower spots, back roll or broom to ensure you have an even coat of sealer on.

!Tip - For a standard driveway approx 60 square meters I would choose a 230mm roller as it fits straight into the drum of sealer.


!Tip - When back rolling take all the weight off the roller. Use a open hand to let the extension pole guide on.


Note - There are no guarantees that you will get a 100% success. It is still possible that the coats could delaminate.