You are using an outdated browser version not supported by this website.
Click here to upgrade your browser

GreenStuf Thermal Underfloor Blanket

GreenStuf Thermal Underfloor Insulation Blanket is designed to insulate residential and commercial spaces with exposed joist floors in new and existing homes.

Key Features
  • No need to cut or trim to fit, simply staple into place between the joists
  • Available in a wide range of pre-cut rolls to fit standard exposed timber joist floors
  • Reduces heat loss through floors and drafts caused by gaps in the floorboards
  • Thermally bonded without harmful chemicals
  • Safe and easy to install without
  • PPE Made locally in New Zealand
Declare LBC Red List Free
Declare LBC Red List Free
Green Tag Certified
Green Tag Certified
Recyclable Content (Post-Consumer)
Post-Consumer Recyclable Content
Recycled Content (Pre-Consumer)
Pre-Consumer Recycled Content
NZ Made
NZ Made
NZ-Owned Business
NZ-Owned Business
Scope of Use
  • Application: Thermal Insulation
  • Fitting: Internal Floors

GreenStuf Underfloor is designed for use in residential and commercial exposed joist floors. GreenStuf Underfloor is available in a range of widths and performance options and can be installed in new and existing buildings with enclosed and semi-enclosed floor spaces.

R-Value Thickness Width Form Nominal GSM Nominal Density
Thermal Conductivity
R1.5 100mm 450-650mm Roll 750 7.5 0.063
R1.8 100mm 450-650mm Roll 1025 10.3 0.054
R2.6 140mm 450-650mm Roll 1650 11.8 0.051
R2.9 140mm 450-650mm Roll 1850 13.2 0.048
Limitations on Use

In open sub-floor spaces, it is recommended that a suitable lining material is applied. In addition to the above recommendation, where wind wash is a concern we suggest selecting the highest R-value GreenStuf Underfloor suitable for the building to maintain maximum thermal performance of the floor system. For more information or advice please contact a GreenStuf account manager.

GreenStuf Underfloor is designed for the thermal insulation of existing and new timber-framed buildings in accordance with NZBC H1 Energy Efficiency requirements. To ensure Building Code compliance, architects and building designers are advised to consult an engineer or the relevant NZ standards before specifying thermal and acoustic insulation products.

Statement of Building Code Compliance

NZBC Compliance: When installed in accordance with the manufacturer’s instructions, GreenStuf insulation will satisfy the 50 year durability clause New Zealand Building Code (NZBC) B2.3.1 (a). GreenStuf meets the relevant clauses of NZBC E3 Internal Moisture, F2 Hazardous Building Materials, and will contribute to meeting H1 Energy Efficiency.

H1 Energy Efficiency: This product will contribute to a building meeting building code Clause H1. All GreenStuf thermal insulation is created to meet with MBIE's new changes.

Fire Regulations: GreenStuf insulation may not be suitable for all applications, as stipulated in the NZBC. Please consult a fire engineer when specifying GreenStuf insulation or contact a GreenStuf account manager for further information.

Acoustic Performance: GreenStuf Underfloor will assist in reducing airborne sound from floors (including booming from footfall) by absorbing reverberant noise under the floor.

Hazardous Building Materials: GreenStuf is non-hazardous.

Durability: GreenStuf has a 50 Year Durability Warranty.

Moisture: GreenStuf is not affected by moisture. Exposure to an atmosphere of 50°C at 90% relative humidity for four days showed moisture absorption by weight of less than 0.03%.


B2 Durability compliant
E3 Internal Moisture compliant
Internal Moisture
F2 Hazardous Building Materials compliant
Hazardous Building Materials
H1 Energy Efficiency compliant
Energy Efficiency
Material Data Sheet
Thermal Underfloor Blanket Data Sheet
BPIR Document
Thermal Underfloor Blanket Install Instructions
Durability Warranty
Existing Homes
GreenStuf Guide
H1 Compliance Toolkit
Insulating Safely Around Downlights
Residential Guide
GreenStuf® Thermal Underfloor Blanket Product Page

GreenStuf thermal and acoustic insulation is made from 100% polyester fibre, with a focus on zero waste and recyclability, it contributes to improved air quality, and is safe to touch.

Product Enquiries

News from GreenStuf

GreenStuf Innovation: Crafting Insulation from 100% Reclaimed Materials NEW
GreenStuf Takeback Programme: A Mission to Divert Waste from Landfills
Closing the Loop on Waste in the NZ Construction Industry
Get a free weekly digest of essential news

New and updated architectural products, design solutions, inspiration, technical advice and more when you sign up for EBOSS.