ToolBase.org logo
The Home Building Industry's Technical Information Resource

Back to Standard View
Search TechnologiesAbout Technology Inventory
 
Browse by Building System


Symbol Legend
Adobe Acrobat Reader required for PDF documents

PDF documents require the free Adobe Reader.


All PDF documents open in a new browser window. Close the browser window to return to the site.

Strawboard Panels

Sheathing constructed of straw based products, designed to replace labor intensive 2x4 stud and drywall construction

These rigid building panels are designed to replace labor intensive 2x4 stud and drywall construction for interior partition walls. The environmental friendly, economical, and recyclable solid panels are made of all natural fibrous raw materials. The durable panels feature thermal and acoustic insulation as well as fire and termite resistance and are available for a variety of applications to speed up the construction processes. Other applications for strawboard panels include load and non-bearing ceilings, roofing, doors, flooring, and prefabricated buildings. Although it has been used in over 20 countries for more than 50 years, strawboard panels have only been introduced to the U.S. in the past few years.

Sixty million acres of wheat are grown each year in the U.S. According to the National Resource Defense Council (NRDC), after harvesting the wheat grain the byproduct straw is an environmental disposal problem (140 million tons per year). Currently being disposed by open air burning, severe seasonal air quality problems have occurred across the country. Introducing strawboard panels to the building industry could reduce if not eliminate this problem. According to a manufacturer it takes about 18 acres of wheat straw (replaceable every year) to build a 1,760 sq. ft. house. It takes the equivalent of one acre of clear cut forest (replaceable every thirty years) to build the same house.

Strawboard panels are made of solid core, compressed wheat or rice straw. High pressure and temperatures (240°C) forces the straw to release a natural resin, that binds the fibers together. The compressed panels are then covered with 100% recycled 69# or 85# paper liners and adhered to both sides with water based non-toxic glue. The standard panel measures 4 feet by 8 feet by 2-1/4 inches and weighs 140 lbs. Custom panel sizes are available ranging from 1 inch to 3 inches thick and 3 feet to 12 feet long. The panel's high density and low oxygen content does not support combustion. Since the panels do not contain added resins, alcohol, or other chemicals, no flammable vapors are produced. The standard 2-1/4 inch panel has a one-hour fire rating, R-value of 3, and noise level reductions from one side to the other of 32 dB (NTC 0.10). For permanent protection against insects and fungal decay and additional fire resistance, the boron compound polybor can be factory added to the core.

The product's workability is similar to wood as it can be sawn, drilled, routed, nailed, screwed, and glued. Lightweight wall attachments such as shelf brackets, picture frames, mirrors, and towel bars can be attached directly to the panel. Up to 35.2 lbs. of direct pull load and 79.2 lbs of shear pull load can be achieved using screws.


Environmental Performance

Straw is a plentiful renewable resource.


Easy

Some manufacturers are overseas. Lead time for U.S. and overseas manufacturers is about 30 days.

Because of the panel's heavy weight, minimal on-site moving is advised. Panels should also be stored dry to prevent swelling. Some contractors experienced difficulties cutting the panels. A sharp carbide-tipped blade in a circular saw (larger than 7-1/4") is suggested. When cutting , don't forget to wear a dust mask. Because of the panel's 2-1/4" width only shallow electrical boxes can be installed. Painting may require several coats, depending on the paint used, since the panels tend to be very absorbtive.


Not Applicable


Not Applicable


ASTM E-84. 1 hour class 2 fire rating.


Not Applicable


After alignment on the pre installed sill plate the panels can be jointed by H-clips with drywall screws at about 24" intervals or permanently bonded using adhesive filler or liquid nail. Standard panels comes with 5/8" diameter service channels at 12" intervals for electrical and communications wiring. To fit electrical power outlets, a high speed router should be used for recessing and grooving. In order to prevent cut edges from swelling, exposed core surfaces must be resealed using a self-adhesive tape or sealer supplied from the manufacturer. The tapered edges allow finishing interior walls the same as with drywall and can be faced with plywood, vinyls, fabrics, or textured paints. For external use, the panels are waterproofed by means of cement stucco or spray-on concrete over wire mesh; concrete/glass fiber mixes directly rolled or sprayed on; or hanging tiles on metal lath, profiled steel, or aluminum.


Not Applicable


Besides the environmental benefits, reusability, and indoor air quality improvement potential, the solid core wheat straw panels feature thermal and sound insulation for interior partition walls. In addition to the 7% savings of floor space compared to conventional 4" construction, contractors report overall cost savings of 18% to 22%. Material cost is between $.80 to $.90 per sf.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.