780 CMR 6.00 — Chapter 6: Wall Construction Amendments

6.00 Chapter 6: Wall Construction Amendments

THIS IS AN UNOFFICIAL COPY OF THE REGULATIONS – OFFICIAL COPIES MUST BE OBTAINED FROM THE SECRETARY OF THE COMMONWEALTH

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780 CMR: MASSACHUSETTS AMENDMENTS TO THE INTERNATIONAL BUILDING CODE 2021

780 CMR 51.00: MASSACHUSETTS RESIDENTIAL CODE (Amendments to the 2021 International Residential Code)

CHAPTER R6 – WALL CONSTRUCTION

Add the following exception to R602.10 Wall bracing: Exception: Unconditioned single-story rooms of areas less than 600 ft 2 thermally isolated from conditioned space. Revise and delete all of Exception #2 in - R602.10.2.2.1 Location of braced wall panels in Seismic Design Categories D0, D1 and D2 Revise and replace section R602.10.3 Required length of bracing, as follows: R602.10.3 Required length of bracing. The required length of bracing along each braced wall line for all detached buildings and townhouses shall be determined by using Table R602.10.3(1) and the applicable adjustment factors in Table R602.10.3(2). Revise and replace section R602.10.4.3 Braced wall panel interior finish material Exception #3 as follows:

Exception #3 - Except for Method LIB, gypsum wall board is permitted to be omitted provided that the required length of bracing in Tables R602.10.3(1) is multiplied by the appropriate adjustment factor in Table R602.10.3(2), unless otherwise required by Section R302.6. Revise and replace R602.10.4.4 Panel joints – Exception #1 as follows: Exception #1. For methods WSP and CS-WSP, blocking of horizontal joints is permitted to be omitted when adjustment factor No. 8 of Table R602.10.3(2) is applied. Revise and replace Table T R602.19.5 as follows: TABLE R602.10.5 MINIMUM LENGTH OF BRACED WALL PANELS METHOD (See Table R602.10.4) MINIMUM LENGTH a

(inches) CONTRIBUTING LENGTH (inches) Wall Height 8 feet 9 feet 10 feet 11 feet 12 feet DWB, WSP, SFB, PBS, PCP, HPS, BV-WSP 48 48 48 53 58 Actual b

GB 48 48 48 53 58 Double sided = Actual Single sided = 0.5 × Actual LIB 55 62 69 NP NP Actual b

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ABW ultimate design wind speed < 140 mph 28 32 34 38 42 48 CS-G 24 27 30 33 36 Actual b

CS-WSP, CS-SFB Adjacent clear opening height (inches)

≤ 64 24 27 30 33 36 Actual b

68 26 27 30 33 36 72 27 27 30 33 36 76 30 29 30 33 36 80 32 30 30 33 36 84 35 32 32 33 36 88 38 35 33 33 36 92 43 37 35 35 36 96 48 41 38 36 36 100 — 44 40 38 38 104 — 49 43 40 39 108 — 54 46 43 41 112 — — 50 45 43 116 — — 55 48 45 120 — — 60 52 48 124 — — — 56 51 128 — — — 61 54 132 — — — 66 58 136 — — — — 62 140 — — — — 66 144 — — — — 72

THIS IS AN UNOFFICIAL COPY OF THE REGULATIONS – OFFICIAL COPIES MUST BE OBTAINED FROM THE SECRETARY OF THE COMMONWEALTH

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METHOD (See Table R602.10.4) Portal header height

8 feet 9 feet 10 feet 11 feet 12 feet PFH Supporting roof only 16 16 16 Note c Note c 48 Supporting one story and roof 24 24 24 Note c Note c PFG 24 27 30 Note d Note d 1.5 × Actual b

CS-PF

16 18 20 Note e Note e 1.5 × Actual b

Revise and replace R602.10.10 Cripple wall bracing - as follows: R602.10.10 Cripple wall bracing. Cripple walls shall be constructed in accordance with Section R602.9 and braced in accordance with this section. Cripple walls shall be braced with the length and method of bracing used for the wall above in accordance with Tables R602.10.3(1), and the applicable adjustment factors in Table R602.10.3(2), except that the length of cripple wall bracing shall be multiplied by a factor of 1.15. Where gypsum wall board is not used on the inside of the cripple wall bracing, the length adjustments for the elimination of the gypsum wallboard, or equivalent, shall be applied as directed in Tables R602.10.3(2) to the length of cripple wall bracing required. This adjustment shall be taken in addition to the 1.15 increase. Delete section R603.9.5 Structural sheathing for stone and masonry veneer.

Revise section R606.2.8 Mortar – by deleting “R606.2.8.2 and R606.2.8.3” from the end of the paragraph. Revise and replace section R606.11 Anchorage - as follows: R606.11 Anchorage. Masonry walls shall be anchored to floor and roof systems in accordance with the details shown in Figure R606.11(1).