Based on data from the USDA Forest Products Lab, I developed
a spreadsheet calculator to estimate the gap size between
boards of varying widths and wood species at varying moisture
levels.
The table above shows a static example of the estimated size of shrinkage gaps in four wood floor scenarios (A-D), based on a calculator developed by Doug Horgan. For a free copy of the calculator as a working Excel file, send a request via email to jlc-editorial@zondahome.com.
The calculator (see chart above for an example) relies on
values from two tables in the Wood Handbook: Table 4.2 (excerpted below)
provides data on the moisture content of wood in equilibrium with
temperature and relative humidity levels.
Table 4.3 (at left) provides shrinkage values for different wood species. To use the calculator, you look up the values in these tables and plug them into the appropriate colored cell.
The results are presented in several ways. “Gaps” are presented in fractions of an inch expressed as a decimal as well as in the number of 16ths, 32nds, and 64ths of an inch, which are often easier to count off a tape measure.
This information can be helpful when a distrustful client wants more than hand-waving from the responsible contractor, or when a client has an engineering bent and likes data.
Return to main article: Avoiding Wood Flooring Gaps