Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 23 - Wood › Section 2303 - MINIMUM STANDARDS AND QUALITY › Subsection 2303.1 - General

Current through Register 1525, July 5, 2024
Structural sawn lumber; end-jointed lumber; prefabricated
				  wood I-joists; structural glued-laminated timber; wood structural panels,
				  fiberboard sheathing (when used structurally); hardboard siding (when used
				  structurally); particleboard;
preservative-treated wood
;
				  structural log members; structural composite lumber; round timber poles and
				  piles;
fire-retardant-treated wood
; hardwood plywood; wood
				  trusses; joist hangers; nails; and staples shall conform to the applicable
				  provisions of this section.
2303.1.1
Sawn lumber.
Sawn lumber used for load-supporting purposes,
				including end-jointed or edge-glued lumber, machine stress-rated or
				machine-evaluated lumber, shall be identified by the grade
mark
of a lumber grading or inspection agency that has been
				approved by an accreditation body that complies with DOC PS 20 or equivalent.
				Grading practices and identification shall comply with rules published by an
				agency approved in accordance with the procedures of DOC PS 20 or equivalent
				procedures. In lieu of a grade
mark
on the material, a
				certificate of inspection as to species and grade issued by a lumber grading or
				inspection agency meeting the requirements of this section is permitted to be
				accepted for precut, remanufactured or rough-sawn lumber and for sizes larger
				than 3 inches (76 mm) nominal thickness.
Approved
end-jointed lumber is permitted to
				  be used interchangeably with solid-sawn members of the same species and
				  grade.
2303.1.2
Prefabricated
				wood I-joists.
Structural capacities and design provisions for
				prefabricated wood I-joists shall be established and monitored in accordance
				with ASTM D 5055.
2303.1.3
Structural glued-laminated timber.
Glued-laminated timbers shall be
				manufactured and identified as required in ANSI/AITC A 190.1 and ASTM D
				3737.
2303.1.4
Wood
				structural panels.
Wood structural panels, when used structurally
				(including those used for siding, roof and wall sheathing, subflooring,
				diaphragms and built-up members), shall conform to the requirements for their
				type in DOC PS 1 or PS 2. Each panel or member shall be identified for grade
				and glue type by the trademarks of an
approved
testing and
				grading agency. Wood structural panel components shall be designed and
				fabricated in accordance with the applicable standards listed in Section 2306.1
				and identified by the trademarks of an
approved
testing and
				inspection agency indicating conformance with the applicable standard. In
				addition, wood structural panels when permanently exposed in outdoor
				applications shall be of exterior type, except that wood structural panel roof
				sheathing exposed to the outdoors on the underside is permitted to be interior
				type bonded with exterior glue, Exposure 1.
2303.1.5
Fiberboard.
Fiberboard
				for its various uses shall conform to ASTM C 208. Fiberboard sheathing, when
				used structurally, shall be identified by an
approved
agency
				as conforming to ASTM C 208.
2303.1.5.1
Jointing.
To ensure tight-fitting assemblies, edges shall be
				manufactured with square, shiplapped, beveled, tongue-and-groove or U-shaped
				joints.
2303.1.5.2
Roof
				insulation.
Where used as roof insulation in all types of construction,
				fiberboard shall be protected with an
approved
roof
				covering.
2303.1.5.3
Wall
				insulation.
Where installed and fireblocked to comply with Chapter 7,
				fiberboards are permitted as wall insulation in all types of construction. In
				fire walls and fire barriers, unless treated to comply with Section 803.1 for
				Class A materials, the boards shall be cemented directly to the concrete,
				masonry or other noncombustible base and shall be protected with an
approved
noncombustible veneer anchored to the base without
				intervening airspaces.
2303.1.5.3.1
Protection.
Fiberboard wall insulation applied on the exterior of
				foundation walls shall be protected below ground level with a bituminous
				coating.