780 CMR, ch. 51, ch. R5, R502.3

Current through Register 1538, January 3, 2025

Subsection R502.3 - Allowable joist spans

Revise and replace section R502.2 as follows:

R502.3 Allowable joist spans.

Spans for floor joists shall be in accordance with Tables R502.3.1(1) and R502.3.1(2). For other grades and species and for other loading conditions, refer to the AWC STJR or the American Wood Council "AWC" Maximum Span Calculator for Wood Joists and Rafters found at: https://www.awc.org/codes-standards/calculators-software/spancalc.

Delete the following from R502.11.1 Design.

After registered design professional, Delete "where required by the statutes of the jurisdiction in which the project is to be constructed in accordance with Section R106.1."

Add new section R506.1.1 Control Joints as follows:

R506.1.1Control Joints. Slabs shall be constructed with control joints having a depth of at least one quarter of the slab thickness but not less than one inch (25 mm). Joints shall be spaced at intervals not greater than 30 feet (9144 mm) in each direction. Control joints shall be placed at locations where the slab width or length changes.

Exception: Control joints may be omitted when the slab is reinforced in accordance with Table R506.1.1. Reinforcement shall be placed at the mid-depth of the slab or two inches (51 mm) from the top of slabs greater than 4 inches (102 mm) in thickness.

Add new Table R506.1.1 as follows:

Table R506.1.1

MAXIMUM DIMENSION OF SLAB OR DISTANCE BETWEEN CONTROL JOINTS (ft.)						WWF WIRE	WWF WIRE SIZE
Slab Thickness (in.)
3.5	4.0	4.5	5.0	5.5	6.0
42	36	32	29	26	24	6 x 6	W1.4 x W1.4
59	52	46	42	38	35	6 x 6	W2.0 x W2.0
86	75	67	60	55	50	6 x 6	W2.9 x W2.9

780 CMR, ch. 51, ch. R5, R502.3

Amended by Mass Register Issue 1532, eff. 10/11/2024.