Designs That Work

Building Materials Property Table
Last Updated: 06/06/2008

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.

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.