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Phone: (425) 828-0433 |
Design Data
Source: ASHRAE Handbook
Perm Values for Common Building Materials
Perm value definition: The unit of permeance. A perm is equal to 1 grain per (sq ft) (hr) (inch of mercury vapor pressure difference).
| Material | Thickness in inches | Perms |
| Brick Masonry | 8 | 0.8 |
| Gypsum Wall Board | .375 | 50.0 |
| Tempered Hardboard | .125 | 5.0 |
| Plywood (exterior glue) | .25 | 0.7 |
| Plywood (interior glue) | .25 | 1.9 |
| Aluminum Foil | .00035 | .05 |
| Polyethylene | .004 | .08 |
| Polyethylene | .008 | .04 |
| Asphalt Saturated and Coated Building Paper | 8.6 lb | 0.2-0.3 |
| Latex Vapor Retarding Paint | .0031 | .45 |
| Exterior Acrylic Paint | .0017 | .40 |
Insulating Values of Building Materials
Insulation
| 2 0" - 2.5 Batt | R-7 |
| 3.0" - 3.5" Batt | R-11 |
| 5.5 - 6.5" Batt | R-19 |
| 7.0 - 6.5" Batt | R-24 |
| 8.5 - 9.0" Batt | R-30 |
| Approx. 12" Batt | R-38 |
Board and Slab Insulation
| Cellular glass | R = 2.86 |
| Glass fiber, organic bonded | R = 4.00 per inch |
| Expanded polystyrene extruded, plain | R = 4. 00 per inch |
| Expanded polystyrene extruded | R = 5.00 per inch |
| Expanded polystyrene, molded beads | R = 4.10 per inch |
| Expanded polyurethane (unlaced) | R = 6.25 per inch |
| Polyisocyanurate | R = 7.04 per inch |
Masonry Materials
| Common brick | R =0.20 per inch |
| Face brick | R = 0.11 per inch |
| Stone (either sandstone or limestone) | R = 0.08 per inch |
| Stucco | R = 0.20 per inch |
Masonry Materials - Concrete
| Concrete type | Density (#/ft3) | R Value |
| Sand & gravel concrete | R = 008 per inch | |
| Cement mortar | 116 | R = 0.20 per inch |
| Gypsum-fiber concrete 87 1/2% gypsum, 12 1/2% wood chips |
51 | R = 0.60 per inch |
| Lightweight aggregates; including expanded shale, clay, or slate; expanded slags, cinders; pumice; vermiculite; also cellular concretes | 120 100 80 60 40 30 |
R = 0 19 per inch R = 0.28 per inch R = 0.40 per inch R = 0.59 per nch R = 0.86 per inch R = 1.11 per inch |
| Perlite | 50 40 30 20 |
R = 0.43 per inch R = 1.08 per inch R = 1.41 per inch R = 2.00 per inch |
| Concrete type | Thickness (inches) |
R Value |
| Concrete blocks, 2-core: Sand and gravel |
4 8 12 |
R = 0.71 R = 1.11 R = 1.28 |
| Cinder aggregate | 3 4 8 10 12 |
R = 1.86 R = 1.11 R = 1.72 R = 1.80 R = 1.89 |
| Lightweight aggregate (expanded shale, clay, slate or slag; pumice) | 3 4 8 12 |
R = 1.27 R = 1.50 R = 2.00 R = 2.27 |
Surface Air Films
Inside (still air)
|
Heat flow UP (through horizontal surface) |
|
| Non-reflective Reflective |
R = 0.61 R = 1.32 |
| Heat flow DOWN (through horizontal surface) |
|
| Non-reflective Reflective |
R = 0.92 R = 4.55 |
| Heat flow HORIZONTAL (through vertical surface) |
|
| Non-reflective | R = 0.68 |
| Outside Heat flow any direction surface, any position |
|
| 15 mph wind | R = 0.17 |
Air Spaces
|
Heat flow UP |
3/4" | 3.5" |
| Non-reflective Reflective |
R = 0.87 R = 2.21 |
R = 0.93 R = 2.66 |
| Heat flow DOWN |
||
| Non-reflective Reflective |
R = 1.02 R = 3.59 |
R = 1.24 R = 9.27 |
| Heat flow HORIZONTAL |
||
| Non-reflective Reflective, once surface |
R = 1.01 R = 3.46 |
R = 1.01 R = 3.40 |
The NW Masonry Guide Table of Contents
Masonry Institute of Washington
Washington State Conference of Mason Contractors
