Cracks And Expansion Joints
What is the best
way to handle cracks and expansion joints in the concrete with a resinous floor
coating installation?
It is first important to understand why the cracks and joints are there. The
expansion joints are form in the wet concrete or cut shortly after the placement
of the concrete to allow for movement. Concrete shrinks when it dries. Expansion
joints when placed properly and frequently enough will limit cracking to the
location of the expansion joints. Crack most often occur most often due to lack
of expansion joints. They may also occur as a result of concrete defects such as
settling of the concrete or from abnormal abuse. It is important to resolve any
concrete related problems causing the cracking before attempting to repair the
issue.
There are several ways to address expansion joints and cracks as a result of
shrinkage. The most obvious way to fill expansion joints is to fill the joint
with a flexible joint sealant. The most cost effective joint sealants are
usually single component urethane joint sealants. The may be supplied in
caulking tubes or in bulk packaging. A backer rod or aggregate if often used to
prefill the joint to prevent the joint sealant from sagging and limiting the
amount of sealant needed for the repair. These are available in self-leveling
formulations and are relatively easy to apply and are used on coated and
uncoated floors and in some cases used after an epoxy floor or epoxy resurfacer
has been installed. The newly installed floor can be re-sawcut through to the
original sawcuts and filled allowing for the slab to move.
If speed is an issue the use a two part joint sealant such as a fast cure
polyurea joint filler may be used in much the same way a single component
polyurethane joint sealant with the added speed of a two part chemically
catalyzed polyurea sealant. The joints may be overfilled and the excess trimmed
providing a smoother look the control joint.
A third way to address filling of expansion joints is by filling with a two
component patching filling compound. 100% solids epoxies along with aggregate or
thickening flour are often used to patch and fill holes and cracks. They dry
quickly and are useful for floor coating installers who can go overtop of the
repair with a resinous flooring system. The shortfall to most epoxies is their
lack of flexibility. This can be particularly problematic for expansion joints.
One remedy for this is the use of a more flexible resin. This flexibility may
still be limited if covered over with and rigid epoxy floor system.
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Vanguard Concrete Coating
229 Crescent NE
Grand Rapids, Michigan 49503
Phone: 616-742-1540
Fax: 616-742-3793
Ian@vanguardconcretecoating.com
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rights reserved by Vanguard Concrete Coating of Grand Rapids, MI. For
residential floors our service area includes the Central, Southwest, & West
Michigan cities of Grand Rapids, Muskegon, Traverse City, Mount Pleasant,
Midland, Bay City, Saginaw, Flint, Howell, Jackson, Lansing, Kalamazoo, South
Haven, Holland, Grand Haven and small cites in-between. For industrial &
commercial clients we service a larger area including Detroit & Ann Arbor, Ohio
/ OH, Northern Indiana / IN, and Northeastern Illinois / IL cities.
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