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INSULATION INSPECTION & IMPROVEMENT
ACOUSTICAL SEALANT CHOICES
AIR LEAK MINIMIZATION
ASBESTOS IDENTIFICATION IN BUILDINGS
BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BRICK LINED WALLS
BRICK VENEER WALL AIR LEAKS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CEILINGS, DROP or SUSPENDED PANEL
DEW POINT TABLE - CONDENSATION POINT
DUCT INSULATION, ASBESTOS PAPER
FIBERGLASS PARTICLE CONTAMINATION
Fiberboard Insulation Sheathing Mold
FIBERGLASS INSULATION MOLD
FIREPROOFING ASBESTOS SPRAY-ON
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
HEAT LOSS in BUILDINGS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION AIR & HEAT LEAKS
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION FACT SHEET- DOE
INSULATION IDENTIFICATION GUIDE
INSULATION INSPECTION & IMPROVEMENT
INSULATION LOCATION - WHERE TO PUT IT
INSULATION R-Values & Properties
LEED GREEN BUILDING CERTIFICATION
LOG HOME ENERGY EFFICIENCY
MOLD in FOAM INSULATION, RESISTANCE
MOISTURE CONTROL in BUILDINGS
NOISE / SOUND DIAGNOSIS & CURE
RIGID FOAM USE INDOORS
SHEATHING, FOIL FACED - VENTS
SLAB INSULATION, PASSIVE SOLAR
STAINS on & in BUILDINGS, CAUSES & CURES
STRAW BALE CONSTRUCTION
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
SWEATING (CONDENSATION) on PIPES, TANKS
Thermal Expansion Cracking of Brick
THERMAL IMAGING, THERMOGRAPHY
THERMAL MASS in BUILDINGS
THERMAL TRACKING Indicates Heat Loss
TRUSS UPLIFT, ROOF
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WALL CONSTRUCTION BARRIER vs CAVITY
WIND WASHING INSULATION At EAVES
WINTERIZE A BUILDING
Balsam wool insulation guide: this article illustrates and describes balsam wool and wood product insulation materials. We discuss the properties of balsam wool, what it is made from, its fire resistance, insect resistance, insulation properties (R-value). We address the frequent question: does balsam wool insulation contain asbestos and we give the history of use and manufacture of balsam wool. We added these examples because of frequent questions about these materials. This document assists building buyers, owners or inspectors who need to identify various insulation materials in buildings by simple visual inspection. We provide photographs and descriptive text of balsam wool insulation and other wood insulating products to permit identification of these materials in buildings.
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The wood product insulating batts shown in these photos was produced by Weyerhaeuser corporation.
In the right hand (and page top) photo of this insulation (basically chopped wood fibers, probably treated with a fire retardant), you can see the brown/tan fibers of insulating material.
Balsam wool insulating blankets, also referred to as "wood cotton" in some patent literature, are shown in our photographs here. These insulating batts of "balsam wool" were produced using wood fibers from tree bark, wood pulp, or other lumber byproducts.
A review of some of the key patents, (described below in the references section of this article) a variety of tree species were described including tree bark and wood byproducts from redwood, [balsam] fir, and others. 
Various sprays were used to give desired properties including for adhesion, fiber control, sizing, and possibly insect and rodent resistance.
When inspecting balsam wool insulation we advise against cutting the kraft paper covering these insulation batts as if the paper is cut a large amount of the insulating material is likely to simply fall out.
If you must make a cut to test or confirm the material or its condition, the cut should be just an inch or so, and you should tape the cut closed after your inspection.
In 2012 we performed a simple combustion test of a sample of Balsam-Wool insulation from an older home. Our photos below illustrate the result. Using an alcohol lamp as a flame source in our lab, and holding a sample of balsam-wool insulation in the flame until its edges glowed, we found on removal from the flame that the insulation would not support combustion.
Balsam wool, depending on the wood species used to produce it, may be naturally insect resistant (Balsam) as are cedar, cypress, and some other wood products. It might have been treated with a fire retardant, I don't yet know (am researching the question). Some fire retardants (borate salts used in cellulose insulation) also seem to be mold resistant and may also be insect resistant.
We estimate that balsam wool has an R value of about 2 to 3.5 in loose fill and about 2 to 3.25 in batts.
We have seen some estimates of an R value of 3.4 per inch for versions of insulation that contain a mixture of wood fibers and chopped paper.
To compare insulating material R-values see our Table of Properties of Insulating Materials
Frequently Asked Questions (FAQs) about Balsam Wool Insulation: properties, R-values, Ingredients, Hazards, Fire Resistance
Questions & answers or comments about the properties & identification of balsam wool & other wood product insulation materials.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.