WAC 51-11-1005   Section 1005: Above-grade walls.

     Section 1005.1 General: Table 10-5, 10-5A and 10-5B list heat-loss coefficients for the opaque portion of above-grade wood stud frame walls, metal stud frame walls and concrete masonry walls (Btu/h • ft² • °F) respectively. They are derived from procedures listed in RS-1, listed in Chapter 7. For intermediate floor slabs which penetrate the insulated wall, use the concrete wall U-factors in Table 10-5B.

     Insulation is assumed to uniformly fill the entire cavity and to be installed as per manufacturer's directions. All walls are assumed to be finished on the inside with one-half inch gypsum wallboard, and on the outside with either beveled wood siding over one-half inch plywood sheathing or with five-eighths inch T1-11 siding. Insulated sheathing (either interior or exterior) is assumed to cover the entire opaque wall surface.

     1005.2 Framing Description: For wood stud frame walls, three framing types are considered, and defined as follows:

     Standard: Studs framed on sixteen inch centers with double top plate and single bottom plate. Corners use three studs and each opening is framed using two studs. Headers consist of double 2X or single 4X material with an air space left between the header and the exterior sheathing. Interior partition wall/exterior wall intersections use two studs in the exterior wall.

Framing weighting factors:	Studs and plates	.19
	Insulated cavity	.77
	Headers	.04

Intermediate: Studs framed on sixteen inch centers with double top plate and single bottom plate. Corners use two studs or other means of fully insulating corners, and each opening is framed by two studs. Headers consist of double 2X material with R-10 insulation between the header and exterior sheathing. Interior partition wall/exterior wall intersections are fully insulated in the exterior wall.

Framing weighting factors:	Studs and plates	.18
	Insulated cavity	.78
	Headers	.04

Advanced: Studs framed on twenty-four inch centers with double top plate and single bottom plate. Corners use two studs or other means of fully insulating corners, and one stud is used to support each header. Headers consist of double 2X material with R-10 insulation between the header and exterior sheathing. Interior partition wall/exterior wall intersections are fully insulated in the exterior wall.

Framing weighting factors:	Studs and plates	.13
	Insulated cavity	.83
	Headers	.04

     1005.3 Component Description: Default coefficients for four types of walls are listed: single-stud walls, metal stud walls, strap walls, and double-stud walls.

     Single-Stud Wall: Assumes either 2x4 or 2x6 studs framed on sixteen or twenty-four inch centers. Headers are solid for 2x4 walls and double 2x for 2x6 walls, with either dead-air or rigid-board insulation in the remaining space.

     Metal Stud Wall: Assumes metal studs spaced on 16 or 24 inch centers with insulation installed to fill wall cavities. Continuous rigid board insulation is applied without creating uninsulated voids in the wall assembly.

     Strap Wall: Assumes 2x6 studs framed on sixteen or twenty-four inch centers. 2x3 or 2x4 strapping is run horizontally along the interior surface of the wall to provide additional space for insulation.

     Double-Stud Wall: Assumes an exterior structural wall and a separate interior, nonstructural wall. Insulation is placed in both wall cavities and in the space between the 2 walls. Stud spacing is assumed to be on 24 inch centers for both walls.

TABLE 10-5

DEFAULT U-FACTORS FOR ABOVE-GRADE WALLS

2 x 4 Single Wood Stud: R-11 Batt
	Siding Material/Framing Type
		Lapped Wood		T1-11
	R-value of Foam Board	STD	ADV	STD	ADV
NOTE: Nominal Batt R-value: R-11 at 3.5 inch thickness Installed Batt R-value: R-11 in 3.5 inch cavity	0	0.088	0.084	0.094	0.090
	1	0.080	0.077	0.085	0.082
	2	0.074	0.071	0.078	0.075
	3	0.069	0.066	0.072	0.070
	4	0.064	0.062	0.067	0.065
	5	0.060	0.058	0.063	0.061
	6	0.056	0.055	0.059	0.057
	7	0.053	0.052	0.055	0.054
	8	0.051	0.049	0.052	0.051
	9	0.048	0.047	0.050	0.049
	10	0.046	0.045	0.047	0.046
	11	0.044	0.043	0.045	0.044
	12	0.042	0.041	0.043	0.042

2 x 4 Single Wood Stud: R-13 Batt
	Siding Material/Framing Type
		Lapped Wood		T1-11
	R-value of Foam Board	STD	ADV	STD	ADV
NOTE: Nominal Batt R-value: R-13 at 3.63 inch thickness Installed Batt R-value: R-12.7 in 3.5 inch cavity	0	0.082	0.078	0.088	0.083
	1	0.075	0.072	0.080	0.076
	2	0.069	0.066	0.073	0.070
	3	0.065	0.062	0.068	0.065
	4	0.060	0.058	0.063	0.061
	5	0.057	0.055	0.059	0.057
	6	0.053	0.052	0.056	0.054
	7	0.051	0.049	0.052	0.051
	8	0.048	0.047	0.050	0.048
	9	0.046	0.045	0.047	0.046
	10	0.044	0.043	0.045	0.044
	11	0.042	0.041	0.043	0.042
	12	0.040	0.039	0.041	0.040

2 x 4 Single Wood Stud: R-15 Batt
	Siding Material/Framing Type
		Lapped Wood		T1-11
	R-value of Foam Board	STD	ADV	STD	ADV
NOTE: Nominal Batt R-value: R-15 at 3.5 inch thickness Installed Batt R-value: R-15 in 3.5 inch cavity	0	0.076	0.071	0.081	0.075
	1	0.069	0.065	0.073	0.069
	2	0.064	0.061	0.068	0.069
	3	0.060	0.057	0.063	0.059
	4	0.056	0.053	0.059	0.056
	5	0.053	0.051	0.055	0.052
	6	0.050	0.048	0.052	0.050
	7	0.047	0.046	0.049	0.047
	8	0.045	0.044	0.047	0.045
	9	0.043	0.042	0.044	0.043
	10	0.041	0.040	0.042	0.041
	11	0.039	0.038	0.041	0.039
	12	0.038	0.037	0.039	0.038

2 x 6 Single Wood Stud: R-19 Batt
	Siding Material/Framing Type
		Lapped Wood			T1-11
	R-value of Foam Board	STD	INT	ADV	STD	INT	ADV
NOTE: Nominal Batt R-value: R-19 at 6 inch thickness Installed Batt R-value: R-18 in 5.5 inch cavity	0	0.062	0.058	0.055	0.065	0.061	0.058
	1	0.058	0.055	0.052	0.060	0.057	0.055
	2	0.054	0.052	0.050	0.056	0.054	0.051
	3	0.051	0.049	0.047	0.053	0.051	0.049
	4	0.048	0.046	0.045	0.050	0.048	0.046
	5	0.046	0.044	0.043	0.048	0.046	0.044
	6	0.044	0.042	0.041	0.045	0.044	0.042
	7	0.042	0.040	0.039	0.043	0.042	0.040
	8	0.040	0.039	0.038	0.041	0.040	0.039
	9	0.038	0.037	0.035	0.039	0.038	0.037
	10	0.037	0.036	0.035	0.038	0.037	0.036
	11	0.036	0.035	0.034	0.036	0.035	0.035
	12	0.034	0.033	0.033	0.035	0.034	0.033

2 x 6 Single Wood Stud: R-21 Batt
	Siding Material/Framing Type
		Lapped Wood			T1-11
	R-value of Foam Board	STD	INT	ADV	STD	INT	ADV
NOTE: Nominal Batt R-value: R-21 at 5.5 inch thickness Installed Batt R-value: R-21 in 5.5 inch cavity	0	0.057	0.054	0.051	0.060	0.056	0.053
	1	0.054	0.051	0.048	0.056	0.053	0.050
	2	0.050	0.048	0.045	0.052	0.050	0.047
	3	0.048	0.045	0.043	0.049	0.047	0.045
	4	0.045	0.043	0.041	0.047	0.045	0.043
	5	0.043	0.041	0.040	0.044	0.042	0.041
	6	0.041	0.039	0.038	0.042	0.041	0.039
	7	0.039	0.038	0.036	0.040	0.039	0.037
	8	0.038	0.036	0.035	0.039	0.037	0.036
	9	0.036	0.035	0.034	0.037	0.036	0.035
	10	0.035	0.034	0.033	0.036	0.035	0.033
	11	0.033	0.033	0.032	0.034	0.033	0.032
	12	0.032	0.031	0.031	0.033	0.032	0.031

2 x 6 Single Wood Stud: R-22 Batt
	Siding Material/Framing Type
		Lapped Wood			T1-11
	R-value of Foam Board	STD	INT	ADV	STD	INT	ADV
NOTE: Nominal Batt R-value: R-22 at 6.75 inch thickness Installed Batt R-value: R-20 in 5.5 inch cavity	0	0.059	0.055	0.052	0.062	0.058	0.054
	1	0.055	0.052	0.049	0.057	0.054	0.051
	2	0.052	0.049	0.047	0.054	0.051	0.048
	3	0.049	0.046	0.044	0.050	0.048	0.046
	4	0.046	0.044	0.042	0.048	0.046	0.044
	5	0.044	0.042	0.041	0.045	0.043	0.042
	6	0.042	0.040	0.039	0.043	0.042	0.040
	7	0.040	0.039	0.037	0.041	0.040	0.038
	8	0.038	0.037	0.036	0.039	0.038	0.037
	9	0.037	0.036	0.035	0.038	0.037	0.035
	10	0.035	0.034	0.033	0.036	0.035	0.034
	11	0.034	0.033	0.032	0.035	0.034	0.033
	12	0.033	0.032	0.031	0.034	0.033	0.032

2 x 6 Single Wood Stud: Two R-11 Batts
	Siding Material/Framing Type
		Lapped Wood			T1-11
	R-value of Foam Board	STD	INT	ADV	STD	INT	ADV
NOTE: Nominal Batt R-value: R-22 at 7 inch thickness Installed Batt R-value: R-18.9 in 5.5 inch cavity	0	0.060	0.057	0.054	0.063	0.059	0.056
	1	0.056	0.053	0.051	0.059	0.056	0.053
	2	0.053	0.050	0.048	0.055	0.052	0.050
	3	0.050	0.048	0.046	0.052	0.049	0.047
	4	0.047	0.045	0.044	0.049	0.047	0.045
	5	0.045	0.043	0.042	0.046	0.045	0.043
	6	0.043	0.041	0.040	0.044	0.043	0.041
	7	0.041	0.040	0.038	0.042	0.041	0.039
	8	0.039	0.038	0.037	0.040	0.039	0.038
	9	0.038	0.037	0.036	0.039	0.038	0.036
	10	0.036	0.035	0.034	0.037	0.036	0.035
	11	0.035	0.034	0.033	0.036	0.035	0.034
	12	0.034	0.033	0.032	0.034	0.034	0.033

2 x 8 Single Stud: R-25 Batt
	Siding Material/Framing Type
		Lapped Wood			T1-11
	R-value of Foam Board	STD	INT	ADV	STD	INT	ADV
NOTE: Nominal Batt R-value: R-25 at 8 inch thickness Installed Batt R-value: R-23.6 in 7.25 inch cavity	0	0.051	0.047	0.045	0.053	0.049	0.046
	1	0.048	0.045	0.043	0.049	0.046	0.044
	2	0.045	0.043	0.041	0.047	0.044	0.042
	3	0.043	0.041	0.039	0.044	0.042	0.040
	4	0.041	0.039	0.037	0.042	0.040	0.038
	5	0.039	0.037	0.036	0.040	0.038	0.037
	6	0.037	0.036	0.035	0.038	0.037	0.036
	7	0.036	0.035	0.033	0.037	0.035	0.034
	8	0.035	0.033	0.032	0.035	0.034	0.033
	9	0.033	0.032	0.031	0.034	0.033	0.032
	10	0.032	0.031	0.030	0.033	0.032	0.031
	11	0.031	0.030	0.029	0.032	0.031	0.030
	12	0.030	0.029	0.028	0.031	0.030	0.029

2 x 6: Strap Wall
	Siding Material/Frame Type
	Lapped Wood		T1-11
	STD	ADV	STD	ADV
R-19 + R-11 Batts	0.036	0.035	0.038	0.036
R-19 + R-8 Batts	0.041	0.039	0.042	0.040

2 x 6 + 2 x 4: Double Wood Stud

			Siding Material/Frame Type
Batt Configuration			Lapped Wood		T1-11
Exterior	Middle	Interior	STD	ADV	STD	ADV
R-19	-------	R-11	0.040	0.037	0.041	0.038
R-19	-------	R-19	0.034	0.031	0.035	0.032
R-19	R-8	R-11	0.029	0.028	0.031	0.029
R-19	R-11	R-11	0.027	0.026	0.028	0.027
R-19	R-11	R-19	0.024	0.023	0.025	0.023
R-19	R-19	R-19	0.021	0.020	0.021	0.020

2 x 4 + 2 x 4: Double Wood Stud
			Siding Material/Frame Type
Batt Configuration			Lapped Wood		T1-11
Exterior	Middle	Interior	STD	ADV	STD	ADV
R-11	--------	R-11	0.050	0.046	0.052	0.048
R-19	--------	R-11	0.039	0.037	0.043	0.039
R-11	R-8	R-11	0.037	0.035	0.036	0.036
R-11	R-11	R-11	0.032	0.031	0.033	0.032
R-13	R-13	R-13	0.029	0.028	0.029	0.028
R-11	R-19	R-11	0.026	0.026	0.027	0.026

Log Walls
	Average Log Diameter, Inches	U-factor
R-value of wood: R-1.25 per inch thickness Average wall thickness 90% average log diameter	6	0.148
	8	0.111
	10	0.089
	12	0.074
	14	0.063
	16	0.056

Stress Skin Panel
	Panel Thickness, Inches	U-factor
R-value of expanded polystyrene: R-3.85 per inch Framing: 6% Spline: 8%	3 1/2	0.071
	5 1/2	0.048
	7 1/4	0.037
	9 1/4	0.030
	11 1/4	0.025
No thermal bridging between interior and exterior splines

Metal Stud Walls: The nominal R-values in Table 10-5A may be used for purposes of calculating metal stud wall section U-factors in lieu of the ASHRAE zone calculation method as provided in Chapter 25 of Standard RS-1.

TABLE 10-5A

Default U-factors for Overall Assembly Metal Stud Walls, Effective R-values for Metal Framing and Cavity Only, and Default Metal Building U-factors

OVERALL ASSEMBLY U-FACTORS FOR METAL STUD WALLS

	R-Value of
	Continuous	Cavity Insulation
Metal	Foam Board
Framing	Insulation	R-0	R-11	R-13	R-15	R-19	R-21
16" o.c.	R-0 (none)	U-0.352	U-0.132	U-0.124	U-0.118	U-0.109	U-0.106
	R-1	U-0.260	U-0.117	U-0.111	U-0.106	U-0.099	U-0.096
	R-2	U-0.207	U-0.105	U-0.100	U-0.096	U-0.090	U-0.087
	R-3	U-0.171	U-0.095	U-0.091	U-0.087	U-0.082	U-0.080
	R-4	U-0.146	U-0.087	U-0.083	U-0.080	U-0.076	U-0.074
	R-5	U-0.128	U-0.080	U-0.077	U-0.074	U-0.071	U-0.069
	R-6	U-0.113	U-0.074	U-0.071	U-0.069	U-0.066	U-0.065
	R-7	U-0.102	U-0.069	U-0.066	U-0.065	U-0.062	U-0.061
	R-8	U-0.092	U-0.064	U-0.062	U-0.061	U-0.058	U-0.057
	R-9	U-0.084	U-0.060	U-0.059	U-0.057	U-0.055	U-0.054
	R-10	U-0.078	U-0.057	U-0.055	U-0.054	U-0.052	U-0.051

24" o.c	R-0 (none)	U-0.338	U-0.116	U-0.108	U-0.102	U-0.094	U-0.090
	R-1	U-0.253	U-0.104	U-0.098	U-0.092	U-0.086	U-0.083
	R-2	U-0.202	U-0.094	U-0.089	U-0.084	U-0.079	U-0.077
	R-3	U-0.168	U-0.086	U-0.082	U-0.078	U-0.073	U-0.071
	R-4	U-0.144	U-0.079	U-0.075	U-0.072	U-0.068	U-0.066
	R-5	U-0.126	U-0.073	U-0.070	U-0.067	U-0.064	U-0.062
	R-6	U-0.112	U-0.068	U-0.066	U-0.063	U-0.060	U-0.059
	R-7	U-0.100	U-0.064	U-0.062	U-0.059	U-0.057	U-0.055
	R-8	U-0.091	U-0.060	U-0.058	U-0.056	U-0.054	U-0.052
	R-9	U-0.084	U-0.057	U-0.055	U-0.053	U-0.051	U-0.050
	R-10	U-0.077	U-0.054	U-0.052	U-0.050	U-0.048	U-0.048

EFFECTIVE R-VALUES FOR METAL FRAMING AND CAVITY ONLY

	Cavity		Insulation
	Nominal Depth, Inches	Actual Depth, Inches	Nominal R-Value	Effective R-Value
	Nominal Depth, Inches	Actual Depth, Inches	Nominal R-Value	16" O.C.	24" O.C.
Air Cavity	any	any	R-0.91 (air)	0.79	0.91
	4	3-1/2	R-11	5.5	6.6
	4	3-1/2	R-13	6.0	7.2
Wall	4	3-1/2	R-15	6.4	7.8
	6	5-1/2	R-19	7.1	8.6
	6	5-1/2	R-21	7.4	9.0
	8	7-1/4	R-25	7.8	9.6
Roof		Insulation is uncompressed	R-11	5.5	6.1
			R-19	7.0	9.1
			R-30	9.3	11.4

DEFAULT METAL BUILDING U-FACTORS

	R-10	R-11	R-13	R-19	R-24	R-30
Faced fiber glass blanket insulation rolled over and perpendicular to structural frame. Metal covering sheets fastened to the frame, holding insulation in place.	0.133	0.127	0.114	0.091	na	na
Faced fiber glass batt insulation suspended between structural frame. Metal covering sheets fastened directly to frame.	0.131	0.123	0.107	0.079	0.065	0.057
Faced fiber glass blanket insulation rolled over and perpendicular to structural frame. Rigid insulation blocks placed over insulation to align with structural frame.	0.102	0.096	0.084	0.065	na	na
Faced fiber glass batt insulation suspended between structural frame. Rigid insulation blocks placed over insulation to align with structural frame.	0.099	0.093	0.080	0.059	0.048	0.041

Concrete Masonry Walls: The nominal R-values in Table 10-5B may be used for purposes of calculating concrete masonry wall section U-factors in lieu of the ASHRAE isothermal planes calculation method as provided in Chapter 25 of Standard RS-1.

TABLE 10-5B

Default U-Factors for Concrete and Masonry Walls

8" CONCRETE MASONRY
WALL DESCRIPTION	CORE TREATMENT
	Partial Grout with Ungrouted Cores			Solid Grout
	Empty	Loose-fill insulated
	Empty	Perlite	Vermiculite
Exposed Block, Both Sides	0.40	0.23	0.24	0.43
R-5 Interior Insulation, Wood Furring	0.14	0.11	0.12	0.15
R-6 Interior Insulation, Wood Furring	0.14	0.11	0.11	0.14
R-10.5 Interior Insulation, Wood Furring	0.11	0.09	0.09	0.11
R-8 Interior Insulation, Metal Clips	0.11	0.09	0.09	0.11
R-6 Exterior Insulation	0.12	0.10	0.10	0.12
R-10 Exterior Insulation	0.08	0.07	0.07	0.08
R-9.5 Rigid Polystyrene Integral Insulation, Two Webbed Block	0.11	0.09	0.09	0.12

12" CONCRETE MASONRY
	CORE TREATMENT
	Partial Grout with Ungrouted Cores			Solid Grout
	Empty	Loose-fill insulated
	Empty	Perlite	Vermiculite
Exposed Block, Both Sides	0.35	0.17	0.18	0.33
R-5 Interior Insulation, Wood Furring	0.14	0.10	0.10	0.13
R-6 Interior Insulation, Wood Furring	0.13	0.09	0.10	0.13
R-10.5 Interior Insulation, Wood Furring	0.11	0.08	0.08	0.10
R-8 Interior Insulation, Metal Clips	0.10	0.08	0.08	0.09
R-6 Exterior Insulation	0.11	0.09	0.09	0.11
R-10 Exterior Insulation	0.08	0.06	0.06	0.08
R-9.5 Rigid Polystyrene Integral Insulation, Two Webbed Block	0.11	0.08	0.09	0.12

8" CLAY BRICK
WALL DESCRIPTION	CORE TREATMENT
	Partial Grout with Ungrouted Cores			Solid Grout
	Empty	Loose-fill insulated
	Empty	Perlite	Vermiculite
Exposed Block, Both Sides	0.50	0.31	0.32	0.56
R-5 Interior Insulation, Wood Furring	0.15	0.13	0.13	0.16
R-6 Interior Insulation, Wood Furring	0.15	0.12	0.12	0.15
R-10.5 Interior Insulation, Wood Furring	0.12	0.10	0.10	0.12
R-8 Interior Insulation, Metal Clips	0.11	0.10	0.10	0.11
R-6 Exterior Insulation	0.12	0.11	0.11	0.13
R-10 Exterior Insulation	0.08	0.08	0.08	0.09

6" CONCRETE POURED OR PRECAST
WALL DESCRIPTION	CORE TREATMENT
	Partial Grout with Ungrouted Cores			Solid Grout
	Empty	Loose-fill insulated
	Empty	Perlite	Vermiculite
Exposed Concrete, Both Sides	NA	NA	NA	0.61
R-5 Interior Insulation, Wood Furring	NA	NA	NA	0.16
R-6 Interior Insulation, Wood Furring	NA	NA	NA	0.15
R-10.5 Interior Insulation, Wood Furring	NA	NA	NA	0.12
R-8 Interior Insulation, Metal Clips	NA	NA	NA	0.12
R-6 Exterior Insulation	NA	NA	NA	0.13
R-10 Exterior Insulation	NA	NA	NA	0.09

Peripheral Edges of Intermediate Concrete Floors

	AVERAGE THICKNESS OF WALL ABOVE AND BELOW
SLAB EDGE TREATMENT	6 inches	8 inches	10 inches	12 inches
Exposed Concrete	0.816	0.741	0.678	0.625
R-5 Exterior Insulation	0.161	0.157	0.154	0.152
R-6 Exterior Insulation	0.138	0.136	0.134	0.132
R-7 Exterior Insulation	0.122	0.120	0.118	0.116
R-8 Exterior Insulation	0.108	0.107	0.106	0.104
R-9 Exterior Insulation	0.098	0.097	0.095	0.094
R-10 Exterior Insulation	0.089	0.088	0.087	0.086

Notes for Default Table 10-5B

1.	Grouted cores at 40" x 48" on center vertically and horizontally in partial grouted walls.
2.	Interior insulation values include 1/2" gypsum board on the inner surface.
3.	Furring and stud spacing is 16" on center. Insulation is assumed to fill furring space and is not compressed.
4.	Intermediate values may be interpolated using this table. Values not contained in this table may be computed using the procedures listed in Standard RS-1.

[Statutory Authority: RCW 19.27A.022, 19.27A.025, 19.27A.045, and chapters 19.27 and 34.05 RCW. 07-01-089, § 51-11-1005, filed 12/19/06, effective 7/1/07. Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-1005, filed 12/17/03, effective 7/1/04. Statutory Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, § 51-11-1005, filed 1/5/01, effective 7/1/01; 98-03-003, § 51-11-1005, filed 1/8/98, effective 7/1/98. Statutory Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, § 51-11-1005, filed 12/19/90, effective 7/1/91.]