Copyright Goodheart-Willcox Co., Inc.
248 Section 2 Foundations and Framing
Code Note
The table in Figure 11‑8 gives the allowable spans of
headers according to the International Residential Code
(IRC) for various load conditions.
Headers are also required across openings in load-
bearing partitions. If loads are very heavy or spans un-
usually wide, a flush beam or strongback may be used.
In such cases, hangers can be used to attach ceiling-
for-floor joists to the flush beam. Strongbacks are dis-
cussed later in this chapter. Figure 11‑9 shows a truss
joist being attached to a microlam header flush beam.
1/2uni2033 plywood
spacer
16d nails
A
2× lumber
1/2uni2033 spacers
2x
pieces
B
1 1uni2033
2
=3
=5
Spacers
1 1uni2033
2
1 1uni2033
2
1uni2033
2
1uni2033
2
5uni2033
2
1uni2033
2
Goodheart-Willcox Publisher
Figure 11‑7. Headers may be built up of several members.
Place plywood spacers 16″–24″ apart on centers.
A—A header for a 2×4 stud wall requires two members with
1/2″ spacers to equal the width of the studs. B—A 2×6
stud wall requires three members with 1/2″ plywood spacers
between each member.
Allowable Header Spans
Header
Supporting Size
Span with 30 lb per
sq ft Snow Load
Span with 50 lb per
sq ft Snow Load
Span with 70 lb per
sq ft Snow Load
20′ 28′ 20′ 28′ 20′ 28′
Roof and Ceiling 2-2×4 3′-6″ 3′-2″ 3′-2″ 3′-6″ 2′-10″ 2′-6″
2-2×10 8′-5″ 7′-3″ 7′-3″ 6′-3″ 6′-6″ 5′-7″
3-2×8 8′-4″ 7′-5″ 7′-5″ 6′-5″ 6′-8″ 5′-9″
Roof, Ceiling,
and One Clear-
Span Floor
2-2×4 3′-1″ 2′-9″ 2′-9″ 2′-5″ 2′-7″ 2′-3″
2-2×10 7′-0″ 6′-2″ 6′-4″ 5′-6″ 5′-9″ 5′-1″
3-2×8 7′-2″ 6′-3″ 6′-5″ 5′-8″ 5′-11″ 5′-2″
Roof, Ceiling,
and Two Clear-
Span Floors
2-2×4 2′-1″ 1′-8″ 2′-0″ 1′-8″ 2′-0″ 1′-8″
2-2×10 4′-9″ 4′-1″ 4′-8″ 4′-0″ 4′-7″ 4′-0″
3-2×8 4′-10″ 4′-2″ 4′-9″ 4′-1″ 5′-5″ 4′-8″
Goodheart-Willcox Publisher
Figure 11‑8. The allowable header spans for exterior walls under various loads according to the IRC.
Kasten-Weiler Construction
Figure 11‑9. When open-web joists are used for a second-
story floor frame, an LVL header may be used to support a
cripple joist.
248 Section 2 Foundations and Framing
Code Note
The table in Figure 11‑8 gives the allowable spans of
headers according to the International Residential Code
(IRC) for various load conditions.
Headers are also required across openings in load-
bearing partitions. If loads are very heavy or spans un-
usually wide, a flush beam or strongback may be used.
In such cases, hangers can be used to attach ceiling-
for-floor joists to the flush beam. Strongbacks are dis-
cussed later in this chapter. Figure 11‑9 shows a truss
joist being attached to a microlam header flush beam.
1/2uni2033 plywood
spacer
16d nails
A
2× lumber
1/2uni2033 spacers
2x
pieces
B
1 1uni2033
2
=3
=5
Spacers
1 1uni2033
2
1 1uni2033
2
1uni2033
2
1uni2033
2
5uni2033
2
1uni2033
2
Goodheart-Willcox Publisher
Figure 11‑7. Headers may be built up of several members.
Place plywood spacers 16″–24″ apart on centers.
A—A header for a 2×4 stud wall requires two members with
1/2″ spacers to equal the width of the studs. B—A 2×6
stud wall requires three members with 1/2″ plywood spacers
between each member.
Allowable Header Spans
Header
Supporting Size
Span with 30 lb per
sq ft Snow Load
Span with 50 lb per
sq ft Snow Load
Span with 70 lb per
sq ft Snow Load
20′ 28′ 20′ 28′ 20′ 28′
Roof and Ceiling 2-2×4 3′-6″ 3′-2″ 3′-2″ 3′-6″ 2′-10″ 2′-6″
2-2×10 8′-5″ 7′-3″ 7′-3″ 6′-3″ 6′-6″ 5′-7″
3-2×8 8′-4″ 7′-5″ 7′-5″ 6′-5″ 6′-8″ 5′-9″
Roof, Ceiling,
and One Clear-
Span Floor
2-2×4 3′-1″ 2′-9″ 2′-9″ 2′-5″ 2′-7″ 2′-3″
2-2×10 7′-0″ 6′-2″ 6′-4″ 5′-6″ 5′-9″ 5′-1″
3-2×8 7′-2″ 6′-3″ 6′-5″ 5′-8″ 5′-11″ 5′-2″
Roof, Ceiling,
and Two Clear-
Span Floors
2-2×4 2′-1″ 1′-8″ 2′-0″ 1′-8″ 2′-0″ 1′-8″
2-2×10 4′-9″ 4′-1″ 4′-8″ 4′-0″ 4′-7″ 4′-0″
3-2×8 4′-10″ 4′-2″ 4′-9″ 4′-1″ 5′-5″ 4′-8″
Goodheart-Willcox Publisher
Figure 11‑8. The allowable header spans for exterior walls under various loads according to the IRC.
Kasten-Weiler Construction
Figure 11‑9. When open-web joists are used for a second-
story floor frame, an LVL header may be used to support a
cripple joist.