DMX 1-step

A homeowner on a building-science forum asked about DMX 1-Step, a dimpled plastic underlayment, for a basement floor. The idea was to install it under LVP (luxury vinyl plank) flooring to create a small thermal break, so the floor stays a bit warmer in winter without adding much thickness. The poster ruled out thicker options like rigid foam board or Dricore panels because they raise the floor height enough to throw off the rise and run of basement stairs.

The one reply came from a forum moderator, who didn't weigh in on the product itself. Instead, he pointed out that the same person had already started a related discussion elsewhere, asking whether R-2.7 insulation is enough of a thermal break for a basement concrete floor, and suggested keeping the conversation in one thread rather than splitting it across multiple posts.

For anyone thinking about the same fix, the underlying question is a real one: basement slabs stay cold, and a thin underlayment under vinyl plank flooring is one of the few ways to add a bit of a thermal break without building up floor height enough to mess with stair dimensions. But this exchange didn't get into how well DMX 1-Step performs for that purpose, or how its insulating value compares with foam board or Dricore. If you're considering a similar basement floor upgrade, it's worth looking into how much of a difference a thin dimpled underlayment actually makes versus thicker insulating subfloor products, and whether the tradeoff in warmth is worth it given your own stair clearances.