N.M. Code R. § 14.7.4.18 – Lintels over Openings

A. General. All openings require a lintel or semi-circular arch over the opening. All lintels, whether of wood or concrete shall bear a minimum of two inches into the length of the wall. Exception: nichos and other shaped voids as defined in 14.7.4.15 NMAC.
B. Bearing limitations. Lintels shall bear a minimum of two inches beyond coved, splayed or rounded bearing portions of openings that are less than the full width of the wall. (Refer to Figure 15 of the earthen building figures supplement).
C. Lintels over openings in stabilized rammed earth walls. Openings less than 2four inches in width shall not require a lintel or semi-circular arched opening. Openings greater than 2four inches in width require lintels as defined in Table 4.
Table 4 Concrete Lintels Over Openings in Rammed Earth Walls (1) Wall width Lintel span Lintel depth Reinforcement (2) Reinforcement Concrete Cover (3) Uniform Load 18” 24” 6” 3- #4 @ 4”o.c. 3” minimum concrete cover on all sides 1000 PLF 36” 6” 3- #4 @ 4”o.c. 48” 6” 3- #4 @ 4”o.c. 60” 6” 3- #4 @ 4”o.c. 72” 8” 3- #5 @ 4”o.c. 84” 8” 3- #5 @ 4”o.c. 96” 8” 3- #5 @ 4”o.c. 20” 24” 6” 3- #4 @ 4”o.c. 4” minimum concrete cover on all sides 1350 PLF 36” 6” 3- #4 @ 4”o.c. 48” 6” 3- #4 @ 4”o.c. 60” 6” 3- #4 @ 4”o.c. 72” 8” 3- #5 @ 4”o.c. 84” 8” 3- #5 @ 4”o.c. 96” 10” 3- #5 @ 4”o.c. 22” 24” 6” 3- #4 @ 5”o.c. 3 1/2” minimum concrete cover on all sides 1700 PLF 36” 6” 3- #4 @ 5”o.c. 48” 6” 3- #4 @ 5”o.c. 60” 6” 3- #4 @ 5”o.c. 72” 8” 3- #5 @ 5”o.c. 84” 10” 3- #5 @ 5”o.c. 96” 10” 3- #5 @ 5”o.c. 24” 24” 6” 3- #4 @ 6”o.c. 3” minimum concrete cover on all sides 2000 PLF 36” 6” 3- #4 @ 6”o.c. 48” 6” 3- #4 @ 6”o.c. 60” 6” 3- #4 @ 6”o.c. 72” 8” 3- #5 @ 6”o.c. 84” 10” 3- #5 @ 6”o.c. 96” 12” 3- #5 @ 6”o.c. 1. 3000 psi minimum concrete at approximately 28 days. 2. Grade 40 steel reinforcement minimum. 3. Steel reinforcement at mid-depth of lintel.
Table 4 Concrete Lintels Over Openings in Rammed Earth Walls (1)
Wall width
Lintel span
Lintel depth
Reinforcement (2)
Reinforcement Concrete Cover (3)
Uniform Load
18”
24”
6”
3- #4 @ 4”o.c.
3” minimum concrete cover on all sides
1000 PLF
36”
6”
3- #4 @ 4”o.c.
48”
6”
3- #4 @ 4”o.c.
60”
6”
3- #4 @ 4”o.c.
72”
8”
3- #5 @ 4”o.c.
84”
8”
3- #5 @ 4”o.c.
96”
8”
3- #5 @ 4”o.c.
20”
24”
6”
3- #4 @ 4”o.c.
4” minimum concrete cover on all sides
1350 PLF
36”
6”
3- #4 @ 4”o.c.
48”
6”
3- #4 @ 4”o.c.
60”
6”
3- #4 @ 4”o.c.
72”
8”
3- #5 @ 4”o.c.
84”
8”
3- #5 @ 4”o.c.
96”
10”
3- #5 @ 4”o.c.
22”
24”
6”
3- #4 @ 5”o.c.
3 1/2” minimum concrete cover on all sides
1700 PLF
36”
6”
3- #4 @ 5”o.c.
48”
6”
3- #4 @ 5”o.c.
60”
6”
3- #4 @ 5”o.c.
72”
8”
3- #5 @ 5”o.c.
84”
10”
3- #5 @ 5”o.c.
96”
10”
3- #5 @ 5”o.c.
24”
24”
6”
3- #4 @ 6”o.c.
3” minimum concrete cover on all sides
2000 PLF
36”
6”
3- #4 @ 6”o.c.
48”
6”
3- #4 @ 6”o.c.
60”
6”
3- #4 @ 6”o.c.
72”
8”
3- #5 @ 6”o.c.
84”
10”
3- #5 @ 6”o.c.
96”
12”
3- #5 @ 6”o.c.
1. 3000 psi minimum concrete at approximately 28 days.
2. Grade 40 steel reinforcement minimum.
3. Steel reinforcement at mid-depth of lintel.

[14.7.4.18 NMAC - Rp, 14.7.4.18 NMAC, 11/15/2016]