July 1, 2010

Concrete Surface Preparation- It’s not as hard as you think …

by Bob Murphy

All surfaces receiving an application of thin film, medium film, laminate or mortar systems must be structurally sound, clean and dry.  Proper surface preparation is an extremely important factor in the immediate and long-term successful performance of applied coating and lining systems.

The contractor responsible for the installation of a coating or lining system shall be provided a substrate that is clean, durable, flat, pitched to specifications, dry and free of surface contaminants.¬† Providing the “proper substrate” is the responsibility of the owner, the owner’s appointed representative and the concrete contractor, unless specifically stated otherwise,

Proper Surface Preparation

Proper surface preparation includes the following:

1.          Inspection of the concrete substrate

2.         Removal and replacement of non-durable concrete

3.         Decontamination of the concrete surface

4.         Creation of surface profile

5.         Repair of surface irregularities

  1. Inspection of the concrete substrate is critical to determine its general condition, soundness, the presence of contaminants, presence of moisture vapor emissions and the best methods to use in preparation of the surface to meet the requirements of the owner or the owner’s appointed representative.¬† A proper evaluation will lead to the selection of the proper tools and equipment to accomplish the objective.

 

  1. Removal and replacement of non-durable concrete must be accomplished prior to installation of the coating or lining system.
  1. Decontamination of the concrete surface requires the removal of oils, grease, wax, fatty acids and other contaminants, and may be accomplished by the use of detergent scrubbing with a cleaner and degreaser, low pressure water cleaning (less than 5,000 psi), steam cleaning, or chemical cleaning.  Rinse thoroughly to achieve a final surface pH between 8.0 and 11.0.  Refer to ASTM D4262.
  1. Creation of surface profile can be accomplished by a number of methods, each utilizing a selection of tools, equipment and materials to accomplish the intended purpose

 

  1. Repair of surface irregularities including spalls, cracks, deteriorated joints, slopes, areas near transition zones, such as around drains and doorways, etc. must be repaired prior to the placement of the polymer system.

Surfaces to receive the coating or  system must be inspected after the surface is prepared to insure that the substrate is sound and structurally durable. Areas found to be unsound or non-durable must be removed and replaced.

Subsequant blog will highlight various methods of surface preparation for concrete surfaces.

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