Question
Dear Mark:

I hope you can help me with my question.  

At the entry to our home we have three concrete steps and a concrete landing leading to our front door.  The first step is 10?x 113? the second is 7?x 89? and the third is 7?x 105? The landing is 47?x 105? The house is all brick, thus there is brick on both sides of the steps and landing.  A flagstone walkway leads up the steps.

We want to beautify the concrete, especially since part of the steps and the landing are discolored.  The landing is covered and a brick arch, about 20 feet high, frames the entry way.  Do you have any suggestions?

Thanks for your time,

John Jones


Answer
Hello,

There are a number of ways to enhance the appearance of existing concrete.  Methods include the following:

Acid Staining

Acrylic Staining

Concrete Overlays

Sawcuts

Stamping (onto a poured overlay)




Acid stains are a mixture of hydrochloric acid,water and inorganic salts.  The acid opens the pores of the concrete and then the metallic salts in the acid react with the hydrated lime (calcium hydroxide) in the concrete.  This process creates a coloring on the concrete.  

There are 8 basic acid stain colors:

black
brown
umber
red
tan
gold
green
blue

Acid stain gives the concrete a marbled and mottled look. The surface will look like different hues within a certain color range,not like a painted surface.

Factors that affect the outcome of acid stain include:

Cement properties and mix design.

Admixtures in the concrete.

Type of aggregate.

Nature of the finished surface on the concrete.

Concrete age and moisture content of concrete when stain is applied.

Efflorescence (salts that leach through the surface of the concrete).

If for some reason your concrete is not a good candidate for acid stain,an acrylic stain can be used.  Your concrete may not contain enough lime for acid stain or may not have a suitable surface for acid stain. Acid stain will highlight cosmetic defects such as stains that cannot be removed.  An Acrylic finish can hide these type of defects.

Acrylic stains act something like paint but are more durable. An application of acrylic stain penetrates the surface of the concrete and creates a semi-transparent coloring. There is no chemical reaction as with acid stain. An acrylic stain will create a more uniform appearance and will not flake off as paint will. Acyrlic stain also comes in a wider variety of color than acid stain.

Acrylic stains are resistant to UV rays,foot traffic,vehicle tires,moisture,mildew,acids and alkalis.

Prepare the surface of the existing concrete for application of acrylic or acid stain by scrubing it with TSP (Trisodium Phosphate) and then rinse. If this will not remove dirt,oil and grease,then try an acid cleaning agent for exterior concrete.  Apply a concrete sealer after the finish has dried. A concrete sealer will protect the finish from stains and moisture.

A concrete overlay is a thick polymer material that is poured over the existing concrete. It can be used to smooth or level uneven or spalled concrete surfaces. The dry time is fast.  For an overlay to be successful,the existing concrete must be structurally sound,without gapping cracks,severe delamination or an unstable sub base. Proper surface preparation of the existing concrete is critical.  Patterns can be stamped into the overlay to replicate natural stone,brick,tile or slate.
Apply concrete sealer after finish has dried.

Saw cutting patterns into the concrete can enhance the look of stains and has the added benefit of increasing foot traction.  Use a 7 inch and a 4 inch diamond blade saw. Mark your lines with chalk. Use the 7 inch blade for longer lines and the 4 inch blade for shorter lines.

Plantings,rock gardens and other structures can enhance the appearance of the walkway.  Good luck. Let me know if I can be of further help.

Mark  Harshman
http://www.mahdrafting.com
Email: [email protected]

http://www.scribd.com/markscrib47