01 / PREP
Start underneath
Underlayment and moisture control
Underlay
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25-year residential warranty6 months to return unopened boxes. Return freight is yours. Full policy
FanFold XPS Flooring Underlayment – 100 sq. ft. (2mm)FanFold Underlayment
The details that make the difference.

Cover more floor in less time. This fanfold XPS underlayment unfolds into wide 46.7" panels that cover 100 square feet per box — fewer seams, less taping, and faster prep than rolled foam. The rigid extruded polystyrene (XPS) core smooths minor subfloor imperfections and creates a firm, stable base for floating laminate and engineered hardwood...
Cover more floor in less time. This fanfold XPS underlayment unfolds into wide 46.7" panels that cover 100 square feet per box — fewer seams, less taping, and faster prep than rolled foam. The rigid extruded polystyrene (XPS) core smooths minor subfloor imperfections and creates a firm, stable base for floating laminate and engineered hardwood floors.
The closed-cell XPS construction acts as a moisture barrier between your subfloor and finished floor — a must over concrete slabs, basements, and ground-level installs. Skip the separate vapor film and protect your floor's locking system from subfloor moisture in one step.
With a 72 IIC / 67 STC sound rating and a 22 dB Delta IIC, this underlayment cuts the hollow sound and footstep noise common with floating floors — a strong choice for upper levels, condos, and multi-family projects with sound requirements. The XPS core also delivers an R-value of 5.0 per inch, adding a thermal break that keeps floors warmer over concrete.
Compatible with both electric and hydronic radiant heat systems, so you can pair it with heated floors without compromising performance.
Panels lay flat right out of the box, cut cleanly with a utility knife, and tape at the seams. No adhesives, no special tools. One box, one installer, one room knocked out before lunch.
Where it works best:
Not for use with: flooring that has pre-attached underlayment pad.
Backed by a 25-year residential and 5-year commercial warranty.
Get materials delivered where you need them, when you need them.
Large orders? Our team coordinates delivery so your materials arrive on time and ready to install.
Buy with confidence — we make returns simple.
For large or special-order items, our team will help review options and next steps.
Think beyond the plank
Round out your project with the right installation materials. Check compatibility with your product and subfloor before ordering.
01 / PREP
Underlayment and moisture control
02 / INSTALL
Adhesives for the application
03 / FINISH
Transitions, trim, and stair noses
04 / EQUIP
Installation tools and supplies