WMP-10 — Dry-Climate 10-Perm Calculator

The 10 refers to the perm rating of the facing material. A 10-perm rating means the facing allows 10 grains of water vapor to pass through one square foot per hour. This classifies it as a moderate vapor retarder — enough restriction to manage moisture in most climates while still allowing some breathability through the wall assembly.

Yes. WMP-10 is generally the most economical white-faced insulation in our lineup. Its PSK-STD construction uses a kraft backing that keeps production costs down while still providing the clean white polypropylene exterior that owners and contractors want. If you need to stretch your budget, WMP-10 is the place to start.

WMP-10 performs well in moderate humidity, but its 10-perm rating offers less vapor transmission than WMP-30 (30 perms) or WMP-50 (50 perms). If your building is located in a consistently humid area — such as the Gulf Coast or Southeast — you may benefit from a higher-perm facing that lets moisture escape more freely and reduces the risk of condensation inside the wall cavity.

WMP-10 is available in 4-foot, 5-foot, and 6-foot widths. Roll lengths come in 30-foot and 50-foot options. R-values range from R-8 through R-25, which covers everything from light-duty walls and partitions to full-thickness roof and ceiling insulation in cold-climate buildings.

The key differences are perm rating and tensile strength. WMP-10 has a 10-perm rating and 40 lbs/in tensile, while WMP-30 has 30 perms and 55 lbs/in tensile. WMP-30 also offers an exclusive 8-foot-wide roll that WMP-10 does not. Choose WMP-10 when budget is the priority and humidity is moderate. Choose WMP-30 for tougher jobsite conditions, high-humidity environments, or when you need wider rolls to cover large surfaces faster.