Underlayment, or carpet cushion, is the pad under wall-to-wall carpet. In a basement, it sits between the floor and the carpet. On the product page, check four things: what the pad is made of, its thickness, its density, and how much floor one roll covers. For a basement or radiant heat, also read the moisture and vapor barrier lines. FloorBox lists these pads in Carpet Underlayment. That page says to compare thickness, density and installation needs first.
Start with what the pad is made of. That is the first difference between two pads. The Carpenter Carpet Cushion Golden Elite AM - 13 mm (30 sqyd) is polyurethane sponge. The Richmond Eco-Cushion Plus Green, 8 mm (135 sqft) is SBR rubber: at least 45% recycled tire rubber, held together with synthetic latex. Its page says it is for residential use. Then compare the lines below.
Thickness is how tall the pad is. Density is how firm it feels underfoot. The Golden Elite AM is 13 mm tall, with a density of 7 lb. The Eco-Cushion Plus is 8 mm (5/16 in.) tall, with a density of 18 lbs/ft³. These numbers do not pick a winner. In a basement, also read the moisture lines below. Not sure? Each product page lets you chat with a flooring specialist or message FloorBox.
For a basement, pick a pad whose page says it can go below grade, meaning below ground level. The Eco-Cushion Plus can go above or below grade, so it fits a basement, and it can go over radiant heat. Its page lists Radiant Heat Compatible: Yes and Moisture Resistant: Yes.
A vapor barrier blocks moisture coming up from the concrete. These two pads are not one: both pages list Vapor Barrier: No. Moisture resistant and vapor barrier are two separate lines. If your basement needs a vapor barrier, ask FloorBox before you order.
Measure the room first with How to Calculate Square Footage for Flooring. Coverage is how much floor one roll covers. The Golden Elite AM covers 270 sq ft (30 sq yd) per roll, 72 in. wide by 37.5 ft long. The Eco-Cushion Plus covers 135 sq ft (15 sq yd) per roll, 72 in. wide by 22.5 ft long. Compare your room total with one roll.
The Golden Elite AM is dyed blue and treated against microbes. The Eco-Cushion Plus has a treatment against mould, mildew and fungus, plus baking soda for odours. It is Green Label Plus and LEED certified. Its R-value of 0.68 says how well it slows heat loss. It has a lifetime warranty. More pads: Carpet Underlayment.
