GreenGuard XP14 / XFP14 Fanfold Underlayment


For use in Replacement Siding Operations to Provide a Level Surface Over Old Siding, Add Insulation and Weather Protection

For the best fanfold siding underlayment available, choose the XP Series. The extruded polystyrene (XPS) foam offers superior stiffness, so your siding job has the smoothest finish possible. The underlayment is extra durable, thanks to flexible plastic facers on both sides. Plus it’s perforated to allow moisture vapor to escape. The cut-and-fold hinge design ensures it lays flat. A perforated reflective facer that can enhance thermal performance is also available.


Product Information

Property Test Method Value
XP14 Siding
XFP14 Siding

Reflective Surface
Nominal Thickness (in)   1/4 1/4
Nominal Width (ft)   4 4
Nominal Length (ft)   50 50
Water Absorption
(Max. % by Volume)
ASTM C 272 2.0 2.0
Water Vapor
Permeance (perm)
(Desiccant Method)
1.7 1.7
Thermal Resistance, R-Value1
(ºF-ft²-h/Btu per in thick)
ASTM C 518
(@ 75ºF Mean
1.0 3.03
Fire & Smoke
Flame Spread2
Smoke Developed2
ASTM E 84/UL 723 25
10 (Class A)
  XP14 XFP14 - reflective
Board Dimensions 4' x 50' 4' x 50'
Nominal Thickness 1/4" 1/4"
Square Feet/Bundle 2 2
Bundle/Pallet 45 45
Square Feet/Pallet 90 90
1 Specimens are aged and tested in accordance with the FTC Rule (16 CFR, Part 460) and ASTM C 578.
2 These numerical flame spread and smoke developed ratings are not intended to reflect hazards presented by these materials under actual fire conditions. All applicable building codes must be followed.
3 System R-value are calculated in accordance with the “ASHRAE Handbook of Fundamentals” using a ½” uniform parallel dead air space. The R-values of this products installed without an air space is 0.9.
GreenGuard XP14 Siding Underlayment_Product Sheet_US_CA_IMG

GreenGuard XP14 Siding Underlayment Product Sheet

GreenGuard Fanfold Underlayment Standard Installation Guide

GreenGuard Fanfold Underlayment Standard Installation Guide

CCMC 12764

Canada - Evaluation Report CCMC 12764-R - Fanfold Underlayment

GreenGuard Siding Underlayment, Sheathing & Roofing Cover Board Safety Data Sheet

GreenGuard Siding Underlayment, Sheathing & Roofing Cover Board Safety Data Sheet

GreenGuard Reflective Sheathing & Siding Underlayment Safety Data Sheet

GreenGuard Reflective Sheathing & Siding Underlayment Safety Data Sheet

Do you need assistance selecting the right product?

Our teams are dedicated to helping make the process as easy as possible and ensure you get the right materials for your needs.

Contact Us

Kingspan Insulation North America

Head Office & Sales Office – North America

Kingspan Insulation LLC

2100 Riveredge Parkway, Suite 175

Atlanta, Georgia



Call: +1(800) 241 4402

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