Slip-resistant support base and method of making

A slip-resistant support base comprising:

• a rigid plate having a plate upper surface, a plate lower surface, and four sides, the plate being configured to support two feet of a ladder positioned on the support base over the plate upper surface;
• an E-shaped barrier fixedly attached to the plate and configured to extend upwardly above the plate upper surface, wherein the barrier is configured to limit movement of the ladder feet along the plate upper surface in three directions when the ladder feet are supported on the support base, and the barrier includes an elongate portion extending along a first side of the plate and first, second, and third sections extending from the elongate portion along the plate upper surface toward a second side of the plate opposite the first side, the first and second sections extending from respective opposite ends of the elongate portion and the third section extending from a position on the elongate portion intermediate between the first and second sections, there being no barrier extending along the second side between the first and second sections, whereby the barrier forms two ladder-foot receiving stations separated by the third section with each station having the barrier on three sides and being open on a fourth side adjacent to the second side of the plate;
• a strap attached to the third section of the barrier and configured to be manually secured to and released from a rung of the ladder when the ladder is positioned with a ladder foot in each station on the support base;
• and
• a resilient substrate made of a closed cell foam and attached to and extending along at least a portion of the plate lower surface, wherein the resilient substrate has an exposed lower expanse opposite the plate lower surface and the lower expanse is characterized by a two-dimensional distribution of downwardly open concave recesses.