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Info-500: Building Materials Property Table

By Building Science Corporation
Created: 2010/04/16

 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 Designs That Work and Enclosures That Work resources. 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.

 

 

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

 


Dry Cup

Permeance

(Perms)1

Wet Cup

Air Permeance
(L/s*m2@75Pa)

 

 

 

 

Sheet Good Building Products

No. 15 asphalt-saturated felt

 

 6

31

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

0.0045 (@ wind pressure 30 mph)

 

HPR=210 cm
FS = 5
SD = 20

 

More Information

Typar®

0.013"

 14

 

0.0023

 

HPR=165 cm
FS = 0
SD = 15

 

 

60-minute roofing paper: Fortifiber Two-Ply Super Jumbo Tex

two ply

11

 

 

 

 

 

 

More Information

Polyethylene

.004-.006 (4-6 mils)

 0.06

0.06

0?

 

FS = 5-35
SD = 15-80

a vapor barrier
appropriate only
for very cold
climates

 

MemBrain™

2-mil

 1

12+

 

 

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

~17

 

 

 

although
published
laboratory data
(Kumaran 2002)
typically gives
gypsum board
painted with latex
paint a value of
~3 perms (dry
cup), BSC has
measured
samples with dry
cup
measurements
of roughly 8-10
perms (see Ueno
et al. 2007)

More information

Exterior acrylic paint

 

 5.5

 

 

 

 

 

 

Semi-gloss vinyl acrylic enamel

 

 6.6

6.6

 

 

 

 

 

Exterior oil-based paint (3 coats)

 

 0.3-1.0

 

 

 

 

 

 

Oil paint
(1 coat + primer)

 

 1.6 - 3

 

 

 

 

various primers
plus 1 coat flat oil
paint on plaster

 

Elastomeric paint

 

 

 

 

 

 

substantial
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 coating, however, and this rule should not be applied to these materials.

  2. Although manufacturers often report this property per ASTM C209 and as a percent 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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