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This article describes insulating panels made from wood fibre.
We include example photos to help identify wood-based fibrous insulating panels, discuss wood insulation R-values, list contemporary wood fibre panel sources and provide supporting research citations.
Page top photo of wood fiber insulating panels is provided courtesy of InspectApedia.com reader Robin.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
Wood fiber (or fibre) insulating board or panels and in some cases coarse wood fiber batt insulation are just that: made from wood, usually wood waste or wood chips or waste, typically shredded and bonded together to form panels of varying thickness, density, and R-values.
Depending on the individual wood fiber panel properties these are used for nail base, for building insulation, for acoustic insulation, and on occasion, often painted or coated, as a finished ceiling or other interior surface.
Here we focus specifically on large, or coarse wood fibre products used in board or batt insulation form.
In a basic form, wood fibers are combined with an inorganic cellular material, a flame retardant, and an organic binder, using heat and pressure to form a wood-based panel that has a wood-like texture, but lighter in weight than solid wood, and with sound absorption and insulating properties making the panels useful also as a wall or ceiling material. (Iwata 1995).
These wood fiber panels have found a wide range of use beyond construction including pallets, bins, boxes, shipping containers, cement forms, even furniture, caskets, and doors. (Owens 1999)
Note that there is a considerable variety of wood-fibre based panels that include products made combining wood fiber with other materials including plastics (Ayrilmis 2011) (Falk 1999) so too will the insulating, durability, and other properties of these products vary.
Panels have been made using a variety of additional materials such as sawdust (Savov 2019) and even ground tire waste (Xyu 2020).
Though wood fiber based panels are, with some justification, described as an eco-friendly product (making use of a renewable resource and making use of wood waste) still there has also been discussion of VOC offgassing from some wood panel products - an old topic that has been addressed in discussions of MDF and HDF and other wood products. (He 2012)
Separately other wood-product insulation materials are discussed at
Below we illustrate coarse wood fiber board products followed by a coarse wood fiber batt insulation, courtesy of a Vancouver CA reader.
Coarse Random-Oriented Wood Strand Fiberboard
Question: are these asbestos-based panels?
...
I'm hoping you can tell me what these panels are and whether they have asbestos in them.
I just purchased them as a cheap way to put up a partition wall at the family cottage and the next day it hit me like a bolt that they might have asbestos!
The panels are 4' x 8' and heavy as all get out! The seller was an older gentleman who said his uncle gave them to him & that he's had them in his garage for over 40 years.
I've attached pictures. #143018 is a side view. #143034 is a corner that is damaged and gives a better view of the materials (shredded). They were originally white but someone painted them grey.
Thanks so much for your help! - Anonymous by private email 2018/02/15
Reply: not likely
Without a lab analysis I cannot say absolutely that an unknown product is asbestos-free, but your photos look to me like a relatively modern wood product, a coarse, random-oriented wood- strand fiberboard product.
If these panels are truly 40 years old that would have them produced in 1978 when asbestos was still used in some building products. But with a few exceptions, principally from cross-contamination, 100% cellulose, non-cementious, wood-based fiberboard products do not contain asbestos.
Watch out: if the binding material in your panels is cementious I think these are a cement fiberboard product such as the strand-reinforced cement board produced by Architonic and shown just below. Such cement products might indeed contain asbestos, depending on when and where they were produced.
Above: wood fibre-reinforced cement board panels describe by the Architonic, a UK source of building products who insists on keeping the actual product manufacturer and identity a secret, Architonic ID: 1184351, prompting us to decline to cite the Archi tonic website directly.
Other readers: see this similar-looking but light-weight panel product [shown above] found by our correspondent above:
Savolit Wood Wool Building Panel | SKANDA Acoustics Ltd,
https://www.savolit.co.uk/products/savolit
Savolit, a lightweight wood wool building panel for external cladding, internal lining, base board for plastering, carrier board for render and internal partition walls.
These panels are listed by SKANDA Acoustics Ltd
67 Clywedog Road North,
Wrexham Industrial Estate,
Wrexham,
LL13 9XN U.K., Tel: 01978 664255
More-modern coarse wood-strand or wood-fibre fiberboard products (popularly "OSB" or oriented strand board) use larger chips of wood either in a random pattern or oriented specifically for strength, and are seen in more-recent patents like
Lindquist, Craig R., John T. Clarke, Peter PS Chin, Michael J. MacDonald, and J. Peter Walsh. "Flat oriented strand board-fiberboard composite structure and method of making the same." U.S. Patent 5,470,631, issued November 28, 1995.
Abstract
An oriented strand board (OSB)-fiberboard composite structure is comprised of a baseboard having three wood strand layers, the wood strands being oriented in space with respect to a board forming machine such that a core layer is comprised of wood strands oriented generally in a random or cross-machine direction and each adjacent layer is comprised of coarse and fine wood strands oriented generally in the machine direction
. In a preferred embodiment, the wood strands comprising each adjacent OSB layer are formed with the coarsest strands located nearest the core layer and the finest strands are located nearest the outer surfaces of each outer board layer.
The OSB-fiberboard composite product is clad with a wood fiber overlay on one major surface of the baseboard.
The composite board is manufactured without warping, by providing particular OSB layer thicknesses, such that the lower OSB layer is about 25% to about 35% thicker than the OSB layer bonded to the fiberboard.
Photo above, courtesy of reader David Blevings, shows a coarse or stranded "fiberboard" wood-sheathing product observed in a 1968 detached bungalow, posted originally
Wood-based or cellulose-based fiberboard products are not asbestos-containing products (normally) and have been in use in the U.S. since the early 20th century, as you will see in
Wilson, Richa & Kathleen Snodgrass, EARLY 20TH-CENTURY BUILDING MATERIALS: FIBERBOARD AND PLYWOOD, [PDF] U.S. Forest Service, USDA Forest Service, Missoula Technology and
Development Center
5785 Hwy. 10 West
Missoula, MT 59808–9361
Phone: 406–329–3978
Fax: 406–329–3719
E-mail: wo_mtdc_pubs@fs.fed.us, retrieved 2018/02/15
Acoustical Solutions, 2420 Grenoble Road, Richmond, VA 23294 USA, Tel: 866.265.0357 Website: https://acousticalsolutions.com Alphasorb panels, (shown above), wood fiber based, various forms, dimensions, thicknesses including Alphasorb ® fiber acoustic panels shown above
Below: this Huber ZIP System® Insulated R-sheathing pops up on searches for wood fiber insulating board but is not a open wood fiber board product like the ones shown elsewhere on this page; more typically it's an OSB or similar wood panel laminated to foam insulation to form an insulated nail base widely used in new construction.
Huber Engineered Woods, Tel: 1.800.933.9220 Website: www.huberwood.com Huber ZIP System® Insulated R-sheathing, a wood panel laminated to foam board, shown above. The company provides more than a dozen installation manuals and example submittal documents for this product line, available at the website we gave above.
best wood SCHNEIDER® External Thermal Insulation Composite System (ETICS) for timber frame constructions, walls from solid wood and for mineral substrates.
The company produces a variety of wood-fibre products including air-injected wood fiber insulation and wood fibre insulating boards (shown above).
Schneider Holz describe the company's Best Wood fiber insulation as:
Joint-free, water vapor permeable wood fiber insulation for air injection, Insulation between rafters, flexible insulation, infilling insulation for wooden framework and timber frame constructions. For an application in restoration works and in the industrial prefabrication.
FIBRE Air injected wood fiber insulation insulates all cavities and guarantees for a joint free insulation.
and give these insulating values:
open blown
Nominal value of thermal conductivity λD: 0,041 [W/(mK)]
Rated value of thermal conductivity λ: 0,043 [W/(mK)]
closed cavities
Nominal value of thermal conductivity λD: 0,038 [W/(mK)]
Rated value of thermal conductivity λ: 0,040 [W/(mK)]
Question: 2020/11/13 Robin said
Hello ... I bought an older home and found insulating panels in the walls that look like wood fiber with a white coating. Can you please advise if it is safe or needs to be removed? Thank you.
Photo: coarse-grained paint-coated wood fiber insulation panel apparently installed between wall studs in a residential building.
Robin: That looks like a wood fibre faced insulating panel; that would be wood or wood-derivative product.
So it's not likely to be an asbestos product but we cannot say with certainty from your photo alone.
More photos (you sent later by email and shown at page top) are helpful as well as would be a bit more information about the building where this insulation was found and its remodeling history.
Tell me:
1. what does the edge of the material look like (see photo at page top)
2. about the back side of it appears and any manufacturer's identification stamps, lot numbers, etc.
3. if it can be removed intact in panels in any case it's easy enough to remove and bag with low risk of stirring up dust as would be made by more aggressive methods like chopping or sawing.
Knowing more information like building age, location, remodeling history, can help make a smart guess about whether or not there is a reasonable chance that a building material contains asbestos. .
Beyond that, if you cannot inspect further and must make a dusty mess then treat the material as presumed to contain asbestos or have a sample tested.
Research on Wood Fibre Panel R-Values, Applications, Properties
Ashori, Alireza, and Amir Nourbakhsh. "Characteristics of wood–fiber plastic composites made of recycled materials." Waste Management 29, no. 4 (2009): 1291-1295.
Abstract:
This study investigates the feasibility of using recycled high density polyethylene (rHDPE), polypropylene (rPP) and old newspaper (rONP) fiber to manufacture experimental composite panels.
The panels were made through air-forming and hot press. The effects of the fiber and coupling agent concentration on tensile, flexural, internal bond properties and water absorption and thickness swelling of wood–fiber plastic composites were studied. The use of maleated polypropylene as coupling agent improved the compatibility between the fiber and both plastic matrices and mechanical properties of the resultant composites compared well with those of non-coupled ones.
Based on the findings in this work, it appears that recycled materials can be used to manufacture value-added panels without having any significant adverse influence on board properties. It was also found that composites with rHDPE provided moderately superior properties, compared with rPP samples.
Ayrilmis, Nadir, and Songklod Jarusombuti. "Flat-pressed wood plastic composite as an alternative to conventional wood-based panels." Journal of composite materials 45, no. 1 (2011): 103-112.
Excerpt:
The WPC panels with wood fiber to polymer ratio of 60 : 40 had a SWR value of 1098.6 N while
the SWR of the panels with wood fiber to polymer ratio of 40 : 60 was 1301.4 N
Chaharmahali, Majid, Jamal Mirbagheri, Mehdi Tajvidi, Saeed Kazemi Najafi, and Yaser Mirbagheri. "Mechanical and physical properties of wood-plastic composite panels." Journal of Reinforced Plastics and Composites 29, no. 2 (2010): 310-319.
Chaharmahali, Majid, Mehdi Tajvidi, and Saeed Kazemi Najafi. "Mechanical properties of wood plastic composite panels made from waste fiberboard and particleboard." Polymer Composites 29, no. 6 (2008): 606-610.
In this paper, we compare woodfiber-plasticand wood-based panel products to determine ifwoodfiber-plastic composites might serve as sub-stitutes for conventional wood-based panel prod-ucts. This comparison is based upon tests per-formed according to the ASTM D 1037, “Standardmethods of evaluating the properties of wood-based fiber and particle panel materials.”
Results indicate that wood fiber-plastic composite panels are inferior to conventional wood-based panels in bending modulus of elasticity and bending modulus of rupture. However, the composite panels performed well in thickness swell and moisture absorption.
He, Zhongkai, Yinping Zhang, and Wenjuan Wei. "Formaldehyde and VOC emissions at different manufacturing stages of wood-based panels." Building and Environment 47 (2012): 197-204.
Abstract:
Formaldehyde and VOC emissions from wood-based panels are recognized as one of the major causes of poor indoor air quality. These emissions may be strongly influenced by the raw materials and manufacturing techniques of the panels. However, there is very little published information regarding this issue.
In this study we determine and compare formaldehyde and VOC emissions, including their species and content, at different manufacturing stages of wood-based panels such as urea-formaldehyde resin, wood chip, wood fiber after resin application, medium density fiberboard, and phenol-formaldehyde resin. We found that:
(1) in total, 34 individual VOCs were identified, but none of them were in all the specimens, indicating considerable VOC species changes during the manufacturing process;
(2) the formaldehyde in wood-based panels came primarily from urea-formaldehyde resin, and there existed a linear relationship between the formaldehyde content in resins and formaldehyde specific emission rate from wood-base panels;
(3) VOCs in wood-based panels mainly came from the wood chips;
(4) the drying and hot-pressing techniques were helpful in reducing the formaldehyde and VOC emissions from wood-based panels. Some suggestions are presented for the control of formaldehyde and VOC emissions from wood-based panels during the manufacturing process.
Iwata, Ritsuo, Hirotoshi Takahashi, Satoshi Suzuki, and Shiro Hanao. WOOD BASED PANELS [PDF] U.S. Patent 5,422,170, issued June 6, 1995.
Abstract:
Wood fiber, inorganic cellular material, flame retardant and an organic binder for binding these materials, are mixed together and hot press formed to give a wood based panel. The resultant panel has a wood like texture, is light weight, has excellent sound absorption properties, and is semi-incombustible, and has a good insulating property for use as a wall or ceiling material.
The effectiveness of a maleated poly-propylene (MAPP) as a couplingagent in extruded wood flour/poly-propylene composites and nonwovenweb wood fiber/polypropylene composites are compared.
Kucuktuvek, Mustafa. "Biobased Sustainable Building Materials." From Micro Scale To Urban Level: 45.
Mnasri, Faiza, Sofiane Bahria, Mohamed El-Amine Slimani, Ouhsaine Lahoucine, and Mohammed El Ganaoui. "Building incorporated bio-based materials: Experimental and numerical study." Journal of Building Engineering 28 (2020): 101088.
A molded structural-wood-fiber product is disclosed that is formed in three dimensions under conditions of heat and pressure. The molded product has the form of a single-piece wood-fiber web consisting of corrugations having indentations along the ridges of the corrugations on both sides of the web.
Sheet facings may be applied to one or both sides of the fiber web to form a stiff, lightweight composite panel that has similar stiffness both along and across the corrugations. Several fiber webs or composite panels may be bonded together in stacked configurations to produce high-strength, light-weight panels, beams or platforms for heavy-duty applications.
The unique structure of the three-dimensional fiber web permits straightforward high-speed manufacture using a rigid mold and one-dimensional pressing forces.
Specific items that can be manufactured utilizing the fiber web and composite panels include pallets, bulk bins, heavy-duty boxes, shipping containers, wall panels, roof panels, cement forms, partitions, poster displays, reels, furniture, caskets, and doors.
Savov, Viktor, Julia Mihajlova, and Rosen Grigorov. SELECTED PHYSICAL AND MECHANICAL PROPERTIES OF COMBINED WOOD BASED PANELS FROM WOOD FIBERS AND SAWDUST [PDF] in Innovation In Woodworking Industry And Engineering Design, 2/2019 (16): 42–
Abstract: The production of wood fiber mass is a very energy-intensive process This is also one of the reasons for the higher cost of this material in comparison of that at particleboards. One possibility to partially solving this problem is the inclusion of industrial wastes, which has not undergone a refining process, in MDF composition.
There is a significant amount of industrial wastes resulting from logging – these are mainly the sawdust resulting from the processing of solid wood with a band saw. It should be pointed out that this method of obtaining solid wood materials is widespread, both globally and in Bul-garia.
This report presents a study on the influence of the content of coniferous sawdust on the properties of combined panels from wood fiber and sawdust. Produced panels were with varia-tion of sawdust content from 0 to 50% and respectively the fiber content was from 100 to 50%. The increase in sawdust content was with a step of 10%.
The main physical and mechanical properties of panels were determined and experimentally-statistical equations for the influence of coniferous sawdust content on the properties of the panels were derived. It was determined at what percentage of sawdust the panels have properties that meet the requirements of the relevant standards for MDF.
Today, the need for factual information on wood-base insulation is greater than at any earlier period. Architects, builders, and owners of homes have need of basic information on the most efficient insulation for their houses.
The Forest Products Laboratory, during the course of its engineering investigations and allied studies extending over the past 48 years, has obtained much basic information on the thermal insulation of wood and wood-base materials, including their influence on fuel economy, comfort of occupants, attic ventilation, vapor barriers, fire hazard, and cold weather condensation.
It is the purpose of this publication to present such information, together with procedures necessary for calculating the thickness of insulation required for a specified installation.
The fullest efficiency to be derived from the use of insulation, as with any material, is in large part dependent on how it is used. The selection of the wrong materials, the use of improper thicknesses of materials, or faulty installation methods can constitute a severe drain on the home owner's income as well as on the Nation's resources.
This publication is intended to aid all who want to acquire a basis for independent judgment regarding the insulation they are buying. To such prudent buyers, a knowledge of the fact that they are using insulation is insufficient.
Accordingly, this publication aims to assist in a careful estimation of where, when, and why insulation is needed; to show how the different wood-base materials meet specific requirements; and to emphasize some of the principles frequently overlooked that should be followed in the proper installation of insulation.
Introduction (excerpts)
Materials used in construction are selected to suit the needs of the service they are expected to perform. For example, in a conventional frame wall, the exterior may be wood siding over wood or fiberboard sheathing fastened to the studs, which act as structural supports for the wall.
The inner wall surface may be lath and plaster or other suitable wall covering. All these materials offer resistance to the transmission of heat from one side to the other, and the heat transmission is proportional to the differences in temperature on opposite sides of the wall.
Stucco or brick or stone veneer may be used in place of wood for exterior wall covering. Other materials may also be used for walls, such as brick, tile, concrete blocks, or stone with the interior surface furred, lathed, and plastered. Such walls, as commonly constructed in the usual thicknesses, will transmit more heat than will conventional frame walls.
Where prefabricated construction is used, the wall panels may be made of light framing members covered on both sides with plywood or other suitable materials. The heat transfer through any of the wall types described can be reduced by increasing the thickness of the basic materials.
For example, 2 thicknesses of wood sheathing could be used in place of the 1 thickness generally used, or the thickness of a masonry wall could be increased above that required for minimum strength.
Generally speaking, however, this means of decreasing heat loss is expensive without being very effective, and there are better means of accomplishing the desired purpose.
The materials used in construction are generally selected on a basis of first-cost, availability, building code requirements, appearance,fire hazard, and similar factors. In some cases, the materials may be selected because they are more resistive to heat transfer than others.
For example, fiberboard products may be used in place of wood sheathing, as a plaster base in place of other plaster-base materials, and sometimes as wall or ceiling surfacing materials in place of plaster.
Structural and finish materials vary widely in thermal properties. Wood is much more resistive to heat transmission than is masonry.
In this respect, 1 inch of Douglas-fir is equal in resistance to heat transmission to about 12 inches of concrete or stone, but it would take about 3 inches of the wood to equal 1 inch of fiberboard.
Tychsen, Detlef. "Process for cutting out panels or the like." U.S. Patent 6,569,272, issued May 27, 2003.
Wechsler, Andrea, and Salim Hiziroglu. "Some of the properties of wood–plastic composites." Building and Environment 42, no. 7 (2007): 2637-2644.
Little data are available on the physical and mechanical properties of nonwoven air-formed wood-fiber and plastic-fiber webs that have been pressed into panels of varying density levels.
This study establishes performance properties for panels with densities of 0.4, 0.7, 1.0, and 1.2 g/cm3 and made from three formulations of wood and synthetic fibers (90% hemlock and 10% polyester; 90% hemlock and 10% polypropylene; and 80% hemlock, 10% polyester, and 10% phenolic resin). Nonwoven webs made from these three formulations were pressed into panels.
Samples cut from these panels were then tested for physical and mechanical properties.
With few exceptions, the physical and mechanical properties increased as panel density increased and as the formulation changed from hemlock and polyester to hemlock and polypropylene to hemlock, polyester, and phenolic resin.
The results provide baseline information for tailoring product formulations and densities to industrial products.
Xing, Cheng, S. Y. Zhang, James Deng, Bernard Riedl, and Alain Cloutier. "Medium-density fiberboard performance as affected by wood fiber acidity, bulk density, and size distribution." Wood science and technology 40, no. 8 (2006): 637-646.
Xu, Xinwu, Feiyu Tian, and Xiaoke Li. "Regenerated Waste Tire Powders as Fillers for Wood Fiber Composites." BioResources 15, no. 2 (2020): 3029-3040.
Abstract:
Waste rubber retains good elasticity and can be regenerated for use in special applications. In this research, wood fiber composites were made with waste tire powders (WTPs) as functional fillers. The physical-mechanical properties of the wood-rubber composite (WRC) panels, i.e., inner bond (IB) strength, static bending modulus (MOE), strength (MOR), and thickness swelling (TS) were assessed. The surface micro-morphology of the WRC panels was quantitatively analyzed and was graphically simulated with Matlab software.
The results showed that WTPs decreased the mechanical strength and modulus of the hybrid composites, which was caused by the weak fiber/WTP interfacial adhesion. The addition of WTPs roughened the surface of composite panels. However, WRC panels showed improved hygroscopic stability and flexibility compared to pure wood fiber composites.
Sanding can flatten the rougher WRC panel surface; however, it brings tiny pits to the surface that are caused by loss of rubber powders. Surface overlaying with resin impregnated paper was found to be effective to cover the tiny pits. This study showed that it is feasible to make value added rubber filled wood fiber composites with satisfactory performance.
Coarse Wood Fiber Batt Insulation
Here, courtesy of a Canadian reader we illustrate coarse wood fiber insulation in batt form, found in a home constructed in 1949 in Vancouver, B.C.
Question: help me identify this insulating board or batt material?
I've been looking through your site but so far cannot find an image that can help me identify what insulating board I have in my suite, which is in a 3-storey residential building constructed in 1949 here in Vancouver, BC, Canada (see photos below).
There is no writing on it - perhaps the writing is on the other side, which I cannot access as that would mean disturbing the building's envelope.
There are some spots where the interior is revealed.
It has a black paper product on its exterior, and its interior appears to be linear wood shavings, kind of like linguini-shaped noodles, jumbled together with adhesive.
In one photo, you can see there's a narrow section where it seems the black paper does not entirely go to the edge, and the interior is exposed down the edge.
A City Building Inspector who saw it called it an insulation board, similar to Donnaconna.
I could take it to a nearby lab and have it tested for asbestos for $30 CAD - would that be useful to your website's body of knowledge?
We believe the wall assembly structure is as follows:
Exterior stucco
Scratch coat
Wire mesh
Insulating board [sic] [Editors's note: there may be coarse wood fibre batts in some of these photos]
Wood wall framing
Interior drywall (3/8" thick, 16" x 24" panels joined with up to 4/8" of concrete plaster
- Anonymous by private email 2021/05/27
Moderator reply:
Thank you for the photos, Anon; Correct me if I'm mistaken but are we looking at coarse wood fiber boards like similar products shown above on this page, or is some of your insulation actually coarse wood fiber batts?
Your photo above appears to be a curved batt, perhaps a cover of asphalt-impregnated paper, sporting a tear that shows the coarse cellulose (wood) fibre interior.
To be clear, I'd call that a batt insulation, not an insulating board. Some insulating board products are shown above on this page and in some other links we cite at the end of this article.
If I'm mistaken perhaps another photo can sort this out.
Watch out: while it's not particularly friable, if that's asphalt-impregnated paper or "asphaltic felt paper" in your photo, that product, in a 1949 home, may contain asbestos.
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In addition to any citations in the article above, a full list is available on request.
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