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Designs That Work
Building Materials Property Table
Last Updated: 03/12/2006

This table presents some of the key technical properties of many of the most common building materials. The information presented has been compiled from:

  • ASHRAE Fundamentals - 2001
  • Moisture Control in Buildings
  • CMHC
  • NRC/IRC
  • IEA Annex 24
  • Manufacturer data

When using this information, it MUST be done in the following context:

  1. Some of these properties are difficult to measure and very sensitive to small changes in the material. That is why ranges are often given and any single value should be considered “representative.”
  2. The importance of the numbers is almost always in the context of the numbers for substitute or alternative materials.
  3. In order to compare numbers, they must be in the same units and obtained under the same standard test conditions—a very tall order. This is the main reason that a table like this has never really been compiled before. The table and its contents will continue to be refined and gaps filled in.
  4. The importance of the numbers is almost always in the context of a given building assembly, for a given climate.
  5. There are very few if any bad building materials, from a building science perspective; bad applications, however, abound.
  6. The most important column in this table is likely to be the “Comments” column because it includes the experience/expertise/unique perspective of many of the leading building scientists in North America. The title of this column could be “OK—now what do these numbers REALLY mean?”

Use this table to augment the information provided in the Building Profiles and Best Practices of the Houses That Work resource. And remember, this resource attempts to supply you with the best knowledge currently available—your professional and field use of it turns it into wisdom.

This table is a work in progress—please direct questions or comments to: info@buildingscience.com.

Building Materials Property Table

 HPR= Hydrostatic Pressure Resistance (AATCC127) SD  = Smoke Development (ASTM E84)
AP = Air permeability (ASTM E2178-01) WA = Water Adsorption (ASTM C209)
FS  = Flame Spread (ASTM E84)  
  MGI/IC - Mold Growth Index for Interior Coatings
(ASTM D3273)
MGI/I&F - Mold Growth Index for Insulation & Facings
(ASTM C1338)		  
Material Typical Relevant Dimension

Water Vapor Permeability
(perm-inch)1

 Water Absorption2 R-Value Other Relevant Properties Comments Web Link for More Information

Dry Cup

Wet Cup
Exterior Sheathings
Plywood (CDX)

3/8"

0.75

3.5

na

0.5

 FS =76-200 SD =130 At saturation, factor of 10 increase in permeability -- 14 - 20.5 perms More Information
OSB

3/8"

0.75

2

na

0.5

 FS = 148 SD= 137 At saturation, marginal increase in permeability - 2.8 - 3.4 perms More Information
Fiberboard - asphalt impregnated

7/16"

14.5

15

2.3 - 7%

1.2

 FS > 75 AP=0.82 Among the most vapor permeable of exterior sheathings More Information
More Information
Thin profile structural sheathing

.078" - .137"

0.5 - 0.6

0.5 - 0.6

na

0.2 - 3.4

 R-value dependent on air space; this sheathing is essentially an exterior vapor barrier More Information
Foil-faced PIR insulation

1"

0.01

0.03

0%

7

 FS = 5
SD = 165 		Combined thermal, vapor transmission & combustion properties must be used appropriately More Information
XPS rigid insulation

1"

1

1

0.10%

5

 FS = 5
SD = 165 AP=0		 Compare/contrast moisture properties to EPS, CAREFULLY More Information
XPS (skinned)

3/8"

0?

0?

  

1.5

 Polypro skin enables the fan-fold but can be removed and greatly affects vapor permeability
EPS rigid insulation (Type II - 1.5 pcf density)

1"

3.5

3%

3.7

 FS = 20
CD = 150 - 300		 There are lots of different grades and densities--and hence toughness--of EPS. Make sure you specify by Type (they range from Type I--1 pcf to Type IX--2 pcf) More Information
Glass mat faced gypsum board (DensGlass®)

1/2"

23

5%

0.56

 FS = 0
SD = 0		 Among the most vapor permeable of exterior sheathings More Information
Wall Claddings
Brick

31/2"

1.7 - 13.7

0.1

 Properties as variable as the material but water storage capacity is always very high More Information
Traditional stucco

7/8"

3.8

5.8

0.1

 Properties as variable as the material but almost always has relatively high vapor permeability
Polymer-modified stucco Vapor permeability is dependent on paint—with latex paint generally in the 2 – 3 perm range; with elastomeric paint highly variable.
Wood lap siding (unfinished)

3/8"

 "35 perms"

0.5

 FS = 69
SD = 98 		35 perms is an equivalent vapor permeance value. Based on both empirical tests (laboratory and test hut conditions), the value is obtained under the following conditions: a 1 Pa air pressure difference between the cladding and environment; crack width between courses of 3/1000 of an inch; and crack length of 18 inches. Note that this value is independent of finishes or coatings on the wood, unless the treatment closes the width or reduces the length of the space between courses.  
Fibercement lap siding (primed all surfaces)

5/16"

1.5

 FS = 0
CD = 5		 Siding comes in different finishes, including texture and coatings (factory priming). Product must be installed over top of a weather barrier--BSC also recommends over furring strips. More Information
Vinyl lap siding

n/a

 "70 perms" 70 perms is an equivalent vapor permeance value. Based on both empirical tests (laboratory and test hut conditions), the value is obtained under the following conditions: a 1 Pa air pressure difference between the cladding and environment; crack width between courses of 2 sheets of paper; and crack length of 18 inches. More Information
Interior Wallboards
Standard paper-faced

1/2"

40

 FS = 15
SD = 0		 Both faces and core highly water vapor permeable; paper faces highly susceptible to mold and mildew growth.
DensArmor Plus™

1/2"

12

23

5%

 FS = 10
SD = 0		 Paper facings are replaced with fiberglass mat facings for increased resistance to moisture, mold and mildew. More Information
Fiberock®

1/2"
Hardie Tilebacker
Hardie Backerboard 500

13/32"

2.8

 FS = 0
SD - 5		 More Information
DensShield®

1/2"

 A tilebacker board with the top face acrylic coating acting as water and moisture barrier. More Information
Durock®

1/2"
Non-paper faced gypsum board:  Fiberock Aqua-TOUGH™ 1/2" 35 .5

FS = 5
SD = 0

 Drainage pattern is embossed on back surface of sheathing More Information
Cavity Fill Insulations
Fiberglass/Rockwool (unfaced batt)

31/2"

120

168

11

 FS = 10
SD = 10		 The thermal performance of all batt insulation depends on independent air sealing components and details. More Information
Cellulose

31/2"

75

<15%

13

 FS < 25
SD < 50		 While the air tightness of cellulose insulation is significantly better than some other common cavity fill insulation, it’s thermal performance still depends on independent air sealing components and details. More Information
Icynene - modified spray urethane

31/2"

16

0%

12.6-14

 FS < 20
SD < 400
AP = 0.008		 While all spray foams are excellent for air sealing, they vary,  often widely, in their density, R-value, blowing agent, water  resistance, vapor permeability. These last two can have the greatest affect on just how you use spray foam in various building assemblies. More Information
Flooring
Hardwood

3/4"
Softwood

3/4"
Glazed tile

3/8"
Synthetic carpet
Organic fiber carpet
Linoleum
Vinyl tile essentially vapor impermeable--not recommended with concrete floors, particularly with high w/c ratios
Vinyl sheet

1/32" - 1/16"

 essentially vapor impermeable--not recommended with concrete floors, particularly with high w/c ratios

Vapor Permeance
(Perms)1

Air Permeance
(L/s*m2@75Pa)
Sheet Good Building Products
No. 15 asphalt-saturated felt

6 (dry) - 31 (wet)

0.4

 vapor permeable at any moisture content
should be compliant with ASTM D226
No. 30 asphalt-saturated felt

0.19

 should be compliant with ASTM D226
Tyvek®

58 (wet)

0.0045 (@ wind pressure 30 mph)

 HPR=210 cm
FS = 5
SD = 20		 More Information
Typar®

0.013"

14 (dry)

0.0023

 HPR=165 cm
FS = 0
SD = 15
60-minute roofing paper: Fortifiber Two-Ply Super Jumbo Tex two ply

More Information
Polyethylene

.004-.006 (4-6 mils)

0.03

0?

 FS = 5-35
SD = 15-80		 a vapor barrier appropriate only for very cold climates
MemBrain™

2-mil

1 (dry) - 10+(wet)

 FS = 75
SD = 450		 well-suited as a vapor pressure boundary for cold and mixed climates More Information
 
Coatings
Vapor retarder primer

0.25 mm

0.5
Latex paint
(primer + sealer)

3.5 - 6.1
Exterior acrylic paint

5.5
Semi-gloss vinyl acrylic enamel

6.6
Exterior oil-based paint (3 coats)

0.3 - 1.0
Oil paint
(1 coat + primer)

1.6 - 3
Elastomeric paint lots of variability in water vapor permeability

1 The water vapor permeability of a material is roughly inversely proportional to its thickness—doubling the thickness halves the permeability. It’s more complicated for films and coatings, however, and this rule should not be applied to these materials.
2 Although manufacturers often report this property per ASTM C209 and as a per cent by weight, this only gives information about the material's POROSITY (overall quantity of water absorbed over an indefinite--long, often 24 hours-- time period) and what is much more useful is the material's water absorption coefficient, a measure of WICKING (initial rate of capillary transport). There is unfortunately NO relationship between the two, no ASTM standard for the water absorption coefficient, and few manufacturers in North America have measured or reported water absorption coefficients. When researching a building product, strongly encourage manufacturers to PROVIDE the water absorption coefficient.

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