Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 15 - Roof Assemblies and Rooftop Structures › Section 1502 - DEFINITIONS › Subsection 1502.1 - General

Current through Register 1525, July 5, 2024
The following words and terms shall, for the purposes of
				  this chapter and as used elsewhere in this code, have the meanings shown
				  herein.
AGGREGATE.
In roofing, crushed stone, crushed
				  slag or water-worn gravel used for surfacing for roof coverings.
BALLAST.
In roofing, ballast comes in the form
				  of large stones or paver systems or light-weight interlocking paver systems and
				  is used to provide uplift resistance for roofing systems that are not adhered
				  or mechanically attached to the roof deck.
BUILT-UP ROOF COVERING.
Two or more layers of
				  felt cemented together and surfaced with a cap sheet, mineral aggregate, smooth
				  coating or similar surfacing material.
INTERLAYMENT.
A layer of felt or nonbituminous
				  saturated felt not less than 18 inches (457 mm) wide, shingled between each
				  course of a wood-shake roof covering.
MECHANICAL EQUIPMENT SCREEN.
A partially
				  enclosed
rooftop structure
used to aesthetically conceal
				  heating, ventilating and air conditioning (HVAC) electrical or mechanical
				  equipment from view.
METAL ROOF PANEL.
An interlocking metal sheet
				  having a minimum installed weather exposure of 3 square feet (0.279
				  m2) per sheet.
METAL ROOF SHINGLE.
An interlocking metal sheet
				  having an installed weather exposure less than 3 square feet (0.279
				  m2) per sheet.
MODIFIED BITUMEN ROOF COVERING.
One or more
				  layers of polymer-modified asphalt sheets. The sheet materials shall be fully
				  adhered or mechanically attached to the substrate or held in place with an
approved
ballast layer.
PENTHOUSE.
An enclosed, unoccupied structure
				  above the roof of a building, other than a tank, tower, spire, dome cupola or
				  bulkhead.
POSITIVE ROOF DRAINAGE.
The drainage condition
				  in which consideration has been made for all loading deflections of the roof
				  deck, and additional slope has been provided to ensure drainage of the roof
				  within 48 hours of precipitation.
REROOFING.
The process of recovering or
				  replacing an existing roof covering. See "Roof recover" and "Roof
				  replacement."
ROOF ASSEMBLY.
A system designed to provide
				  weather protection and resistance to design loads. The system consists of a
				  roof covering and roof deck or a single component serving as both the roof
				  covering and the roof deck. A roof assembly includes the roof deck,
vapor retarder
, substrate or thermal barrier, insulation,
vapor retarder
and roof covering.
The definition of "Roof assembly" is limited in application
				  to the provisions of Chapter 15.
ROOF COVERING.
The covering applied to the roof
				  deck for weather resistance, fire classification or appearance.
ROOF COVERING SYSTEM.
See "Roof
				  assembly."
ROOF DECK.
The flat or sloped surface not
				  including its supporting members or vertical supports.
ROOF RECOVER.
The process of installing an
				  additional roof covering over a prepared existing roof covering without
				  removing the existing roof covering.
ROOF REPAIR.
Reconstruction or renewal of any
				  part of an existing roof for the purposes of its maintenance.
ROOF REPLACEMENT.
The process of removing the
				  existing roof covering, repairing any damaged substrate and installing a new
				  roof covering.
ROOF VENTILATION.
The natural or mechanical
				  process of supplying conditioned or unconditioned air to, or removing such air
				  from, attics, cathedral ceilings or other enclosed spaces over which a roof
				  assembly is installed.
ROOFTOP STRUCTURE.
An enclosed structure on or
				  above the roof of any part of a building.
SCUPPER.
An opening in a wall or parapet that
				  allows water to drain from a roof.
SINGLE-PLY MEMBRANE.
A roofing membrane that is
				  field applied using one layer of membrane material (either homogeneous or
				  composite) rather than multiple layers.
UNDERLAYMENT.
One or more layers of felt,
				  sheathing paper, nonbituminous saturated felt or other
approved
material over which a steep-slope roof covering is
				  applied.