With continued advancements to our formula, we have been able to improve our performance in both strength and expansion and contraction properties. Still, plastic is not as strong as wood, and, as a rule of thumb, you should plan to support plastic about 25% more than you would support wood.

When using BearBoard over 12ft long, we recommend you use our plastic biscuit/clip system. This allows the board to expand and contract lengthwise without damaging the fasteners. The boards will not expand or contract widthwise, so whatever gap you choose will stay that way.

192” x 100° x .000045 = .86”

To calculate expansion, multiply the number of inches of the board by the change in temperature in degrees Fahrenheit by the decimal .000045.

In the example to left, you see that a 16ft board will change 7/8″ in length from the cold of winter to the heat of summer. That is just under ½” on each end and too far for a screw to bend.

Plan your gaps according to the temperature when laying the board and your climate fluctuations.


The recommended span for residential applications is 16” on-center for all BearBoard 5/4 x 6 deck boards and 24″ on-center for all 2 x 6 deck boards.


BearBoard must be gapped end-to-end, based on the length of the board and temperature at installation. This will allow for the expansion of the material in warmer temperatures and the contraction of the material in cooler temperatures. You can expect that a 12ft board will expand 1/8” on each end when installed at 60°F based on an expected increase of 40°F. Therefore, in this example, you would gap the boards ¼” in end-to-end installation.