By Tim Carter
Jan 13, 1997, 08:19
© Tim Carter
DEAR TIM: Our builder is trying to convince us to use
colored stamped concrete for our front walk. I'm worried
that the textured finish will not last. Is stamped concrete
as good as regular concrete? What can be done to insure
a long lasting job? Is it possible to colorize regular
concrete after it is poured? D. A.
DEAR D. A.: I think I can significantly reduce your
anxiety level about pattern stamped concrete. It is
a fantastic technique to improve the visual characteristics
of otherwise bland concrete. Concrete in and of itself
is a premier building material. Adding color and texture
to it simply enhances its appeal to me.
Pattern stamping is not really new. It has been done
for years in one form or another. As a child I would
often see the name stamp of the concrete contractor
who installed the sidewalks in my neighborhood. Steep
concrete roadways were often stamped with horizontal
lines to increase traction. The pattern stamped residential
concrete your builder is using has been around for almost
4 decades.
The stamping processes available today can create over
90 different patterns. They include a wood boardwalk
look, slate, cobblestone, brick, flagstone, ceramic
tile, etc. When the installer blends different colors
with the wet concrete the effect is dramatic. If you
have visited theme parks or other attractions there
is a good chance you have walked across stamped concrete
thinking it was a natural stone product! Contractors
who use newer molds and pattern stamps can create unbelievable
results.
There is no reason why your front walk shouldn't last
for many years. As long as your contractor follows all
of the known industry standards for pouring concrete,
your stamped walk should outlast you. I would suggest
that you install 1/2 inch steel reinforcing bars on
24 inch centers in both directions of your walkway.
Be sure this steel ends up in the middle of the 4 inch
thick sidewalk. In addition, make sure that the concrete
is ordered with a minimum compressive strength of 4,000
pounds per square inch. If you choose to install stamped
concrete in your driveway, insist on a minimum thickness
of 6 inches. Be sure the concrete is cured after it
is
installed.
Concrete shrinks when it dries. This shrinkage usually
amounts to 1/16 inch for every ten feet you pour. This
shrinkage produces internal stresses within the concrete.
To prevent random cracking you must install control
joints. These joints are saw cut lines often created
the day after the pour. They should be cut to a minimum
depth of 1/4 the thickness of the slab.