402.1.5.2 Offset Siding Attachment

When an airspace separates the siding from direct contact with the foam plastic sheathing, the siding shall be attached in accordance with the Residential Code of New York State, Section R703.4 and Table R703.4, to minimum 1 × 3 wood or minimum 33 mil steel hat channel furring placed over the foam sheathing. Furring shall be attached through the foam sheathing to wall framing in accordance with the Residential Code of New York State, Table R703.3.2.2, in regard to minimum fastening requirements and maximum foam sheathing thickness limitations to support siding dead load. The components and cladding design wind pressure determined in accordance with the Residential Code of New York State, Table R301.2(2), shall not exceed the allowable design wind pressure value in accordance with the Residential Code of New York State, Table R703.3.2.2. For 25 (1.2 kPa) psf siding weight in accordance with the Residential Code of New York State, Table R703.3.2.2, the Seismic Design Category shall not exceed D₀ for 16 inch o.c. furring or C for 24 inch o.c. furring. When placed horizontally, wood furring shall be preservative treated wood or naturally durable wood and fasteners shall be corrosion resistant in accordance with the Residential Code of New York State, Section R317. Steel hat channel furring shall have a minimum G60 galvanized coating.

Exception: Furring shall not be required over foam plastic sheathing located behind anchored stone and masonry veneer installed in accordance with the Residential Code of New York State, Section R703.7. Veneer ties shall be installed in accordance with the Residential Code of New York State, Section R703.7.4.1.

TABLE 402.1.5.2 FURRING MINIMUM FASTENING REQUIREMENTS FOR APPLICATION OVER FOAM PLASTIC SHEATHING TO SUPPORT SIDING WEIGHT^1,2

FURRING MATERIAL	FRAMING MEMBER	FASTENER TYPE AND MINIMUM SIZE	MINIMUM PENETRATION INTO WALL FRAMING (inches)	FASTENER SPACING IN FURRING (inches)	MAXIMUM THICKNESS OF FOAM SHEATHING (inches)						ALLOWABLE DESIGN WIND PRESSURE (PSF)
					16"OC FURRING4			24"OC FURRING4
					SIDING WEIGHT:			SIDING WEIGHT:
					3 psf	11 psf	25 psf	3 psf	11 psf	25 psf	16"oc Furring	24"oc Furring
Minimum 1 × Wood Furring3	Minimum 2 × Wood Stud	Nail (0.120" shank; 0.271" head)	11/4	8	4	4	1.5	4	2	1	42.6	28.4
				12	4	2	1	4	1.5	0.5	28.4	18.9
				16	4	2	0.5	4	1	DR	21.3	14.2
		Nail (0.131" shank; 0.281" head)	11/4	8	4	4	2	4	3	1	46.5	31.0
				12	4	3	1	4	2	0.75	31.0	20.7
				16	4	2	0.75	4	1.5	DR	23.3	15.5
		#8 wood screw5	1	12	4	4	1.5	4	3	1	98.9	66.0
				16	4	3	1	4	2	0.5	74.2	49.5
				24	4	2	0.5	4	1	DR	35.1	23.4
		1/4" lag screw5	11/2	12	4	4	3	4	4	1.5	140.4	93.6
				16	4	4	2	4	3	1	79.0	52.7
				24	4	3	1	4	2	0.5	35.1	23.4
Minimum 33 mil Steel Hat Channel or Minimum 1 × Wood Furring3	33 mil Steel Stud	#8 screw (0.285" head)	Steel thickness +3 threads	12	3	1.5	DR	3	0.5	DR	52.9	35.3
				16	3	1	DR	2	DR	DR	39.7	26.5
				24	2	DR	DR	2	DR	DR	26.5	17.6
		#10 screw (0.333" head)	Steel thickness +3 threads	12	4	2	DR	4	1	DR	62.9	41.9
				16	4	1.5	DR	3	DR	DR	47.1	31.4
				24	3	DR	DR	2	DR	DR	31.4	21.0
	43 mil or thicker Steel Stud	#8 screw (0.285" head)	Steel thickness +3 threads	12	3	1.5	DR	3	0.5	DR	69.0	46.0
				16	3	1	DR	2	DR	DR	51.8	34.5
				24	2	DR	DR	2	DR	DR	34.5	23.0
		#10 screw (0.333" head)	Steel thickness +3 threads	12	4	3	1.5	4	3	DR	81.9	54.6
				16	4	3	0.5	4	2	DR	61.5	41.0
				24	4	2	DR	4	0.5	DR	35.1	23.4

For SI: 1 inch = 25.4 mm; 1 pound per square foot (psf) = 0.0479 kPa. DR = design required.

1. Table values are based on: (1) minimum 3/4-inch (19.1 mm) thick wood furring and wood studs of Spruce-Pine-Fir or any softwood species with a specific gravity of 0.42 or greater per AFPA/NDS, (2) minimum 33 mil steel hat channel furring of 33 ksi steel, and (3) steel framing of indicated nominal steel thickness and minimum 33 ksi steel for 33 mil and 43 mil steel and 50 ksi steel for 54 mil steel or thicker. Steel hat channel shall have a minimum 7/8-inch (22.2 mm) depth.

2. Nail fasteners shall comply with ASTM F1667, except nail length shall be permitted to exceed ASTM F1667 standard lengths. Self-drilling tapping screw fasteners for connection of siding to steel framing shall comply with the requirements of AISI S230. Specified fasteners in accordance with Section R703.4 or the siding manufacturer's approved installation instructions shall meet all other requirements in ASTM F1667 or AISI S230 or be otherwise approved for the intended application.

3. Where the required siding fastener penetration into wood material exceeds 3/4 inch (19.1 mm) and is not more than 11/2 inches (38.1 mm), a minimum 2 × wood furring shall be used unless approved deformed shank siding nails or siding screws are used to provide equivalent withdrawal strength allowing connection to 1× wood furring.

4. Furring shall be spaced a maximum of 24 inches o.c. in a vertical or horizontal orientation. In a vertical orientation, furring shall be located over wall studs and attached with the required fastener spacing. In a horizontal orientation, furring strips shall be fastened at each stud intersection with a number of fasteners equivalent to the required fastener spacing. In no case shall fasteners be spaced more than 24 inches (0.6 m) apart.

5. Lag screws shall be installed with a standard cut washer. Lag screws and wood screws shall be pre-drilled in accordance with AFPA/NDS. Approved self-drilling screws of equal or greater shear and withdrawal strength shall be permitted without pre-drilling.