MA Roofing Contractor cheat sheet

The Massachusetts State Building Code is 780 CMR, which adopts the International Building Code (IBC) and International Residential Code (IRC) with Massachusetts amendments; roofing provisions sit in 780 CMR Chapter 15 (roof assemblies) and Chapter 9 (fire protection of roofs).

780 CMR applies statewide, but cities and towns may adopt local amendments and stretch energy provisions; the local building official (inspector of buildings) enforces the code and issues the roofing permit.

A permit is required to install, replace, or recover a roof covering, except for ordinary repair of less than one square (100 sq ft) where no structural change occurs; check the local jurisdiction, since thresholds vary by municipality.

Reroofing over an existing covering is limited to a maximum of two layers total; a third layer requires complete removal of existing coverings down to the deck.

New roof coverings may not be installed over more than one existing layer where the existing covering is water-soaked, deteriorated, or of a type incompatible with the new material.

Where 25 percent or more of the roof area is replaced within any 12-month period, the entire roof must be brought into compliance with current code for roof covering, flashing, and, in many cases, energy (insulation) requirements.

Re-roofing must maintain the existing roof drainage: replacement of roof coverings must not reduce the size or capacity of gutters, downspouts, or scuppers below code minimum.

Ice barrier is required in Massachusetts because of its cold climate: a self-adhering membrane must extend from the eave edge to a point at least 24 inches inside the exterior wall line of the heated building.

Steep-slope coverings (asphalt shingles, wood shakes, tile, slate, metal shingles) are installed on roofs with a slope of 2:12 or greater; low-slope coverings (built-up, modified bitumen, single-ply, sprayed polyurethane) are used below 2:12.

Asphalt shingles: minimum slope 2:12 with underlayment; between 2:12 and 4:12, double underlayment (or a manufacturer-approved system) is required; below 2:12 the shingles must be a listed low-slope assembly.

Wood shingles and shakes require a minimum slope of 3:12 (shingles) or 4:12 (shakes) depending on exposure, and must be installed over spaced or solid sheathing per manufacturer instructions and code.

Clay and concrete tile and slate require structural support designed for the material weight; minimum slope is typically 2.5:12 for tile with underlayment and higher for some slate installations.

Metal roof panels: minimum slope depends on panel profile and seam type (standing seam can go as low as 1:12 or lower with sealant; through-fastened panels generally require 3:12 or more).

Built-up roofing (BUR): minimum slope 1:4 (3:12 is common); must be applied over a base sheet and use at least two plies; gravel surfacing adds weight and must be accounted for in structural design.

Single-ply membranes (EPDM, TPO, PVC) are installed on low-slope roofs; seams are either adhesive, tape, or heat-welded, and the manufacturer's listed assembly governs fastener spacing and attachment.

Fastener spacing, nail placement, and exposure (headlap) must follow the manufacturer's printed instructions and code; high-wind zones require enhanced fastening (six nails per shingle instead of four in many Massachusetts coastal areas).

Roof deck sheathing must be minimum 15/32-inch (nominal 1/2-inch) wood structural panel or 1-inch nominal lumber, unless the manufacturer's listing or engineered design requires thicker material.

Sheathing panels must be spaced 1/8 inch at edges to allow expansion; gaps reduce buckling and are required by code for wood structural panels.

Underlayment: minimum one layer of No. 15 asphalt-saturated felt (or ASTM D226 Type I) is required under asphalt shingles; a second layer is required on slopes from 2:12 to 4:12.

Synthetic underlayment may substitute for felt only if it is listed and approved for the application; it must meet or exceed the water-resistance performance of the felt it replaces.

Ice dam protection: a self-adhering waterproofing membrane is required along eaves, in valleys, around chimneys, skylights, and other penetrations where ice dams can form; in Massachusetts the membrane must extend at least 24 inches inside the interior wall line.

Flashing: corrosion-resistant metal (typically 26-gauge galvanized steel, copper, or aluminum) must be used; step flashing is required at sidewalls, and counterflashing must be embedded in masonry at least 1 inch.

Valley flashing must be at least 12 inches wide (or per manufacturer) and installed over the underlayment; open valleys require metal panning with a minimum 16-inch width in many code editions.

Drip edge is required at eaves and rakes; it must be corrosion-resistant and installed under the underlayment at eaves and over it at rakes, directing water away from the fascia.

Design loads include dead load (roofing materials, sheathing, insulation, ceiling), live load (minimum 20 psf for ordinary roofs, 12 psf for certain low-slope roofs), snow load, and wind load.

Massachusetts ground snow load varies by location; use the value from the adopted code map or the local building official's determination, then apply exposure, thermal, and importance factors.

Roof dead load must include the weight of the covering; asphalt shingles are roughly 2 to 4 psf, tile and slate 6 to 20 psf, and built-up roofing with gravel 5 to 6 psf.

Rafter and ceiling joist sizing follows the IRC span tables or engineered design; rafters must be tied by collar ties or ceiling joists to resist outward thrust at the walls.

Ridge boards, hips, and valleys must be sized to carry the loads imposed by the rafters, and hip and valley rafters must be designed for the increased span and load.

Roof slope is rise over run expressed as a ratio (4:12 = 4 inches rise per 12 inches run); slope in degrees = arctangent(rise/run), and pitch = rise/span.

Roof area multiplier for a gable roof: multiply the plan area by the slope factor = sqrt(1 + (rise/run)^2); a 4:12 roof has a factor of about 1.054, a 6:12 about 1.118, a 12:12 about 1.414.

Wind uplift must be addressed: in high-wind zones, sheathing fastening, roof-to-wall connectors, and covering attachment must be designed for the uplift pressure from ASCE 7.

Roof coverings are classified A, B, or C by fire resistance under ASTM E108 or UL 790; Class A is the most fire-resistant and Class C the least.

Class A covering: effective against severe fire exposure, with a 2-hour fire test; Class B: moderate exposure, 1-hour test; Class C: light exposure, 10-minute test.

Massachusetts generally requires Class A roof coverings for certain occupancies and where the building is within a specified distance of a lot line or another structure; the building official determines the required class.

Roof coverings must be listed and labeled for the fire classification; the classification applies to the assembly, not just the top surface, so the underlayment and deck can affect the rating.

Fire separation between buildings and roofs is governed by 780 CMR Chapter 7 (fire and smoke protection) and Chapter 6 (types of construction); the required separation depends on occupancy group and construction type.

Buildings with a fire-resistance-rated roof assembly (such as a roof over an occupancy separation) must maintain that rating through the roof covering installation; penetrations must be firestopped.

Where a roof is used as a means of egress or a fire department access route, the roof surface and supporting structure must be designed for the imposed loads and the roof covering must not create a slipping or fire hazard.

Rooftop-mounted photovoltaic panels and equipment must not reduce the required fire classification of the roof assembly and must meet setback requirements from the roof edge for firefighter access.

Massachusetts adopts the Stretch Energy Code (225 CMR 22) for many municipalities and the base energy code for others; roof insulation R-values and air-sealing requirements depend on which code the town has adopted.

Attic ventilation: minimum 1 square foot of net free ventilation area per 150 square feet of attic floor area; the ratio can be 1:300 if a vapor barrier is installed or if at least 50 percent of the vent area is in the upper portion of the roof.

Vents must balance intake (soffit) and exhaust (ridge or gable) so air moves through the attic; at least 50 percent of the required vent area should be intake vents.

Insulation must be installed to maintain a vented air space of at least 1 inch between the insulation and the roof sheathing; baffles at the eaves keep the soffit vents open.

Air sealing is required at the ceiling plane: gaps around chimneys, recessed lights, plumbing penetrations, and top plates must be sealed to prevent warm moist air from entering the attic.

Vapor retarders are required on the warm side of the insulation in cold climates; in Massachusetts, a Class I or II vapor retarder is typical for ceilings, but the code permits alternatives where drying potential is provided.

Ice dams are controlled by air sealing, insulation, and ventilation, not by heat cable alone; ice barrier membrane and proper flashing are required at eaves regardless of ventilation.

Ducts in attics must be insulated and sealed; duct leakage to the outside must be limited per the energy code, and ducts should be located inside the building thermal envelope where practical.

Massachusetts consumer protection law (M.G.L. c. 93A) prohibits unfair or deceptive acts in trade or commerce; violations can result in actual damages, multiple damages, and attorney's fees.

Home improvement contractors must provide a written contract for work over $500 that includes the contractor's name, address, license number, description of work, materials, total price, payment schedule, and start and completion dates.

Massachusetts requires a 3-day right of rescission for certain home solicitation contracts; the notice must be in writing and the consumer may cancel within three business days.

Contractors must disclose lien rights and provide a lien waiver or release upon payment; Massachusetts has a mechanic's lien statute (M.G.L. c. 254) with strict notice and filing deadlines.

The Home Improvement Contractor (HIC) law (M.G.L. c. 142A) requires registration with the Office of Consumer Affairs and Business Regulation and provides a guaranty fund for certain homeowner losses.

Deposits and payment schedules must be reasonable and tied to progress; Massachusetts limits the deposit a contractor may require and requires written receipts for payments.

Warranty obligations: work must be performed in a workmanlike manner and comply with the building code; express warranties must be in writing, and implied warranties of habitability apply to residential work.

Contractors must carry liability insurance and, for employees, workers' compensation; a certificate of insurance should be provided to the homeowner before work begins.

The Massachusetts Construction Supervisor License (CSL) is issued by the Board of Building Regulations and Standards (BBRS) and is required for construction, alteration, repair, or demolition of buildings, including roofing work, above certain thresholds.

A CSL is required for one- and two-family residential work and for all other construction; the license is issued in categories (unrestricted, restricted, and specialty) and must be renewed every two years.

Continuing education is required for license renewal: 12 hours of approved continuing education per two-year cycle, including code-related and safety topics.

The construction supervisor is responsible for ensuring that work complies with the code, that permits are obtained, and that the work is inspected at required stages.

Unlicensed practice is prohibited and subject to fines and cease-and-desist orders; a licensed supervisor may not allow an unlicensed person to supervise work that requires a license.

The supervisor must keep the permit and approved plans on the job site and make them available to the building official on request.

Changes to approved plans must be submitted to the building official for approval before the work is performed; the supervisor is responsible for ensuring that revisions are documented.

The supervisor must ensure that workers are properly trained and that safety requirements, including fall protection, are enforced on the job site.

OSHA requires fall protection for employees working at heights of 6 feet or more above a lower level on construction sites (29 CFR 1926.501).

Fall protection options include guardrail systems, safety net systems, personal fall arrest systems, and warning line systems combined with a safety monitoring system for certain roofing work.

Personal fall arrest systems must limit the maximum arresting force to 1,800 pounds and bring the employee to a complete stop within 3.5 feet; anchorage must support at least 5,000 pounds per employee.

Ladder safety: ladders must extend at least 3 feet above the landing, be set at a 4:1 angle, and be secured; the top of the ladder must support the intended load.

Roofing work near the edge requires a warning line at least 6 feet from the edge (or 10 feet for mechanical equipment) when a safety monitoring system is used.

Scaffolds must be designed and erected by qualified persons, planked fully, and have guardrails; employees must not work on scaffolds during storms or high winds.

Head protection, eye protection, and foot protection are required where there is a hazard; roofing workers must wear hard hats when overhead hazards exist.

Massachusetts requires employers to carry workers' compensation insurance and to post the required OSHA and workers' compensation notices on the job site.