How to clean and seal stamped concrete

by Rick Sanders
(Southern IL)

Q. We poured and stamped a concrete walkway last fall. During the 28 day wait period the temperature dropped to around freezing and stayed there. The walkway lay covered with a tarp all winter without being sealed.

It now has dirt, etc. stains in which I hope to be able to pressure wash away with a concrete cleaner. Can you tell me any special tricks to removing the dirt stains and the downfalls of sealing this concrete after sitting for 4 months or if there are any special products I should try using?

Thank you

A. Try cleaning the concrete with just a pressure washer first. This usually removes any dirt and mild staining from the concrete without having to use any concrete cleaners.

Don't get the tip of the pressure washer too close to the surface of the concrete or you could damage it. Use a fanned tip with a back and forth motion.

If the pressure washer doesn't completely remove a stain, you can try a mild cleaning agent like simple green. Scrub the stained area with a stiff brush and rinse. It may take a few applications to completely remove the stain.

There are no "downfalls" to sealing your stamped concrete after 4 months. Just make sure the concrete is clean and completely dry. Don't apply the sealer if rain is in the forecast. We use a decorative concrete sealer from L.M. Scofield.

It is better to roll or spray on 2 thin coats of sealer 24 hrs apart. The sealer will enhance the color in the concrete and darken it a bit.

A decorative sealer will form a film on top of the concrete surface. This film can be slippery when it gets wet. You can add an additive called shark grip to the sealer that will help keep the concrete from being slippery when it gets wet.