Protection from Decay | Library builder

Moisture and warm air are catalysts of fungus, which causes dry rot that can destroy a building.

In addition to calling for ventilation to control moisture, the code also requires decay-resistant wood wherever moisture can come in contact with structural wood. Some areas of the country are more conducive to decay than others. The code requires naturally durable wood or preservative-treated wood in the following situations:

• Wood joist or the bottom of the wood floor structure if less than 18" from exposed ground. (See “Joists & Girder Protection" illustration.)

• Wood girders if closer than 12" from exposed ground.

• Wall plates, mudsills, or sheathing that rest on concrete or masonry exterior walls less than 8" from exposed ground. (See “Exterior Wall Decay Protection" illustration.)

• Sills or sleepers that rest on a concrete or masonry slab in direct contact with the ground, unless separated from the slab by an impervious moisture barrier. (See “Decay Protection from Slab" illustration later in this chapter.)

• The ends of wood girders entering exterior masonry or concrete walls having less than %" clearance on tops, sides, and ends. (See “Ends of Girders in Masonry or Concrete" illustration.)

• Posts or columns that support permanent structures and are themselves supported by a masonry concrete slab or footing in direct contact with the ground. (See “Post and Column Decay-Resistant Wood" illustration.)

Space on top, sides, and end must be V2" or girder needs to be of decay — resistant wood.

Nailing

Nailing is one of the most important parts of framing. Table 2304.9.1, Fastening Schedule (see IBC Nailing Table), is taken directly from the IBC 2009. The table shows use of alternate nails. The 3” x 0.131” nail is the most common nail gun nail used for framing.

TABLE 2304.9.1 FASTENING SCHEDULE

CONNECTION	FASTENINGam	LOCATION
1. Joist to sill or girder	3 — 8d common (2’/2 0.131 ) 3 — 3 0.131 nails 3 — 3 14 gage staples	toenail
2. Bridging to joist	2 — 8d common (2’/2 X 0.131 ) 2 — 3 0.131 nails 2 — 3 14 gage staples	toenail each end
3. 1 6 subfloor or less to each joist	2 — 8d common (2’/2 0.131 )	face nail
4. Wider than 1 6 subfloorto each joist	3 — 8d common (2’/2 0.131 )	face nail
5. 2 subfloor to joist or girder	2 — 16d common (3’/2 0.162 )	blind and face nail
6. Sole plate to joist or blocking Sole plate to joist or blocking at braced	16d (3V2 0.135 ) at 16 o. c. 3 0.131 nails at 8 o. c. 3 14 gage staples at 12 o. c. 3 — 16d (3V2 0.135 ) at 16	typical face nail
wall panel	4 — 3 0.131 nails at 16 4 — 3 14 gage staples per 16	braced wall panels
7. Top plate to stud	2 — 16d common (3V2 0.162 ) 3 — 3 0.131 nails 3 — 3 14 gage staples	end nail
8. Stud to sole plate	4 — 8d common (2’/2 0.131 ) 4 — 3 0.131 nails 3 — 3 14 gage staples 2 — 16d common (3V2 0.162 ) 3 — 3 0.131 nails 3 — 3 14 gage staples	toenail end nail
9. Double studs	16d (3V2 0.135 ) at 24 o. c. 3 0.131 nail at 8 o. c. 3 14 gage staple at 8 o. c.	face nail
10. Double top plates Double top plates	16d (3V2 0.135 ) at 16 o. c. 3 0.131 nail at 12 o. c. 3 14 gage staple at 12 o. c. 8-16d common (3V2 0.162 ) 12-3 0.131 nails 12-3 14 gage staples	typical face nail lap splice
11. Blocking between joists or rafters to top plate	3 — 8d common (2’/2 0.131 ) 3 — 3 0.131 nails 3 — 3 14 gage staples	toenail
12. Rim joist to top plate	8d (2V2 0.131 ) at 6 o. c. 3 0.131 nail at 6 o. c. 3 14 gage staple at 6 o. c.	toenail
13. Top plates, laps and intersections	2 — 16d common (3V2 0.162 ) 3 — 3 0.131 nails 3 -3 14 gage staples	face nail
14. Continuous header, two pieces	16d common (3’/2 0.162 )	16 o. c. along edge
15. Ceiling joists to plate	3 — 8d common (2’/2 0.131 ) 5 — 3 0.131 nails 5 — 3 14 gage staples	toenail
16. Continuous header to stud	4 — 8d common (2’/2 0.131 )	toenail

(continued)

For SI: 1 inch = 25.4 mm.

a. Common or box nails are permitted to be used except where otherwise stated.

b. Nails spaced at 6 inches on center at edges, 12 inches at intermediate supports except 6 inches at supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.

c. Common or deformed shank (6d — 2 0.113 ; 8d — 2V2 0.131 ; 10d — 3 0.148 ).

d. Common (6d — 2 0.113 ; 8d — 2V2 0.131 ; 10d — 3 0.148 ).

e. Deformed shank (6d — 2 0.113 ; 8d — 2V2 0.131 ; 10d — 3 0.148 ).

f. Corrosion-resistant siding (6d — 17/8 0.106 ; 8d — 23/8 0.128 ) or casing (6d — 2 0.099 ; 8d — 2V2 0.113 ) nail.

g. Fasteners spaced 3 inches on center at exterior edges and 6 inches on center at intermediate supports, when used as structural sheathing. Spacing shall be 6 inches

on center on the edges and 12 inches on center at intermediate supports for nonstructural applications.

h. Corrosion-resistant roofing nails with 7/16 — inch-diameter head and 11/2-inch length for 1/2-inch sheathing and 1 3/4-inch length for 25/32-inch sheathing.

i. Corrosion-resistantstapleswithnominal7/16-inchcrownand 11/8-inchlengthfor 1/2-inchsheathingand 1 1/2-inchlengthfor25/32-inchsheathing. Panelsupportsat 16 inches (20 inches if strength axis in the long direction of the panel, unless otherwise marked).

j. Casing (1V2 0.080 ) or finish (1V2 0.072 ) nails spaced 6 inches on panel edges, 12 inches at intermediate supports.

k. Panel supports at 24 inches. Casing or finish nails spaced 6 inches on panel edges, 12 inches at intermediate supports.

l. For roof sheathing applications, 8d nails (2V2 0.113 ) are the minimum required for wood structural panels.

m. Staples shall have a minimum crown width of 7/16 inch.

n. For roof sheathing applications, fasteners spaced 4 inches on center at edges, 8 inches at intermediate supports.

o. Fasteners spaced 4 inches on center at edges, 8 inches at intermediate supports for subfloor and wall sheathing and 3 inches on center at edges, 6 inches at intermediate supports for roof sheathing.

p. Fasteners spaced 4 inches on center at edges, 8 inches at intermediate supports.

Termite Protection

Framers in many areas of the country have to be concerned about protection against termites. Pressure preservative-treated wood, naturally termite-resistant wood, or physical barriers can be used to prevent termite damage. The following map shows termite infestation probability by region.

Termite Infestation Probability

Conclusion

An important part of your job as a lead framer is being aware of the building codes that apply to framing in your part of the country. You should be aware of how to use the code and of any revisions to those codes. Although locating information you need in the code books is often the hardest part of using the codes, the “Framing Index" at the beginning of this chapter should make this easier for you. It’s a good feeling to know that you have framed a building the way it’s specified according to code.

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