Making Beautiful Concrete

Making
beautiful concrete
Distributor of specialty forming products uses stains and
coatings to enhance surfaces textured by form liners

dmiring a retaining wall, the
old man said to its creators, “I
was a mason for 30 years.
Where in the world did you get
people to lay up a wall like
this?” The wall, made of cast-in-place
concrete, had deceived even a pro—so
well did it simulatenatural stone.
Behind it all was the hand of Larry
Karlson, an innovative distributor of
specialty forming products who had
persuaded local authorities to build the
wall in concrete instead of treated wood

A

planks. He then showed them how to
make the concrete look like natural
local stone. Karlson supplied the patterned form liners that provided the
rock texture, and led his own crewin
applying the nine different colors of
stain needed to complete the illusion.
This is but one example of the proactive approach Karlson takes in encouraging the greater use of visually pleasing
concrete. His company, Karlson Forming Specialties, Amery, Wis., sells and
rents a range of forming products, in-

Larry Karlson

BY M.K. HURD

Hollow-backed lightweight urethane form linerswere used to produce the stone texture in this Minnesota highway overpass.
The recessed horizontal band was formed with two layers of high-density polyethylene, custom cut to produce the triangular
detail. A cementitious coating provides the warm, uniform tan color.

© R.W. Steiger

cluding form liners
and rustication (recess) strips of polystyrene, polyurethane and polyethylene. Having astrong sense of
forming knowhow, Karlson goes
beyond just supplying forming
products; he also
helps contractors learn how to use
these products properly and cost-effectively. He even works with architects during the design phase to
show how the form-liner products
can contribute to project aesthetics.
A case in point is the work now in
progress on bridges for 71⁄2 miles of
freewaybypassing downtown Milwaukee.

Liner applications
For the Milwaukee project, Karl-

© R.W. Steiger

Figure 1. On the Milwaukee job,
workers carefully position 35x42-inch
broken-rib form-liner panels on the
large heavy-duty gangs used for single-sided retaining-wall forming. The
polystyrene foam liners are 2 inches
thick, providing a relief of 11⁄2 inches
for the ribs. Detail shows theconcrete
ribs in a partially stripped wall, where
some of the liner remains.

Figure 2. This “cobblestone” concrete wall near Waukesha, Wis., has deceived
even experienced stone masons. To achieve the authentic look, Karlson supplied
polyurethane form liners with a river-stone pattern and then carefully stained the
completed concrete. Total cost for the liners and staining was $5.50 per squarefoot. Using local gravel as a color guide, he chose nine different colors of waterborne stain, applying it after pressure washing the wall when the concrete was 30
days old. Note the carefully detailed corner, where precise fitting of abutting liners
maintained the fidelity of the rock simulation. Plain concrete caps project beyond
the wall face to minimize water drainage over the coloredsurfaces.

son has supplied a variety of multiuse polyurethane and single-use expanded-polystyrene foam liners.
Both types of liners are being used to
produce rock texture on various
parts of the bridges.
Polyurethane. Able to produce
textures with up to 41⁄2 inches reveal,
the polyurethane liners are being
used to create the deeper reveals and
authentic rock simulations. Karlson
supplies themultiuse liners on a
rental basis at $2.25 to $2.50 per
square foot of concrete surface area
constructed. These liners are most
efficient when numerous reuses are
possible, such as for long walls of
uniform height.
Polystyrene. The 2-inch-thick
polystyrene liners, which can produce ribs or rocks with 11⁄2-inch reveal, were used to form ribbed parapets and retaining walls, such as the...