Substrate Preparation for Finish Flooring

by Ron Leiseca, CSI, CCPR, Miami Chapter

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statements such as "pitch floor as required" or "fill in all voids, bug holes and floor imperfections" are an imposition on the specialty contractor

Last month we touched on floor finishing tolerances, new equipment being utilized, and the use of the F scale for floor flatness and levelness (see the September, 1999 issue).

This month, I want to touch on the issue of field tolerances on finished flooring.

Before you say that this was covered last month, I want to give you a quick explanation as to why we must deal with the two issues on a separate basis. The finish flooring contractor, be he installing carpet, tile, VCT, terrazzo, wood or other finishes will inherit, to a large extent, the characteristics of the underlying surface, typically cement in South Florida.

As the influence of the substrate will affect the final product, you must understand the possibilities and properly temper your expectations in your specifications.

Some of the floor finishes, such as terrazzo, wood and marble can make some adjustments to address variations in the pitch of the substrate, but they can not remediate the errors of other trades, nor should they be expected to do so. Statements in the specifications such as "pitch floor as required" or "fill in all voids, bug holes and floor imperfections" are an imposition on the specialty contractor, as he does not have the knowledge to "know" what conditions he will inherit. I would rather see under Division 3, either under concrete or concrete finishing that the substrate must be finished and repaired to eliminate such problems prior to the work starting under other sections of the work.

This approach more directly ties in the responsibility to the correct trade, and minimizes guessing and contingency allowances by other trades, and can lead to greater expectation on their performance.

In developing your field tolerances for finished flooring, you would commonly state a pitch of the floor such as 1/4" per 10 lineal feet. This figure and the tighter 1/8-3/16" per 10 lineal feet are commonly utilized in commercial terrazzo, wood and marble flooring. In addition, in conditions where positive drainage is desired such as kitchen and preparation areas, a separate requirement for positive drainage of the floor no less than 1/8" per 10 lineal feet can be included.

Sections are interconnected due to overlapping needs and influences, so assume the proper expectations and make sure your related sections are beefed up to allow for the subsequent trades to have a good basis to perform properly.

Education is a wonderful and necessary thing! Read and keep abreast of developments in your industry.

As a manufacturers representative and CCPR, I am involved in the education of our colleagues in the design sector as well as contractors and related industry members. From these and other contacts, as well as the experiences of other representatives, I am writing a series of articles on common problems that effect selection and use of some materials. The situations will be generic in nature and no specific manufacturer will be cited, for we are trying to share information and educate all of segments of the Construction Team. 

Remberto J. Leiseca, CSI, CCPR, rjlassoc@ix.netcom.com.

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