MI Roofing Contractor key terms

The vertical rise of a roof for each 12 inches of horizontal run, written as a ratio such as 4:12. Slope determines which roof coverings, underlayments, and flashing details are permitted.

A roof with a slope of 2:12 or less, typically covered with membrane, built-up, or modified bitumen systems that rely on continuous waterproofing rather than rapid runoff. Drainage and ponding are key concerns.

A roof steeper than about 3:12, commonly finished with asphalt shingles, metal, or tile. Steep-slope assemblies shed water quickly but require proper underlayment and eave protection against ice dams.

The lower edge of a sloped roof that overhangs the exterior wall. The eave contains the drip edge, fascia, soffit, and often intake ventilation and ice-dam protection.

The inclined edge of a gable roof running from the eave up to the ridge. Rake edges receive rake trim, drip edge, and gable-end flashing to shed water away from the wall.

The highest horizontal line where two opposing roof planes meet. Ridges are capped with ridge shingles or a ridge vent and are a common location for attic exhaust ventilation.

The internal intersection where two sloping roof planes meet, concentrating water flow. Valleys require special underlayment and flashing because they carry the largest volume of runoff on the roof.

An external intersection where two sloping roof planes meet, forming a convex corner running from eave to ridge. Hip roofs require hip and ridge cap materials and careful flashing at the hip line.

The structural surface that supports the roofing materials, usually plywood or OSB panels fastened to rafters or trusses. Deck condition and fastener pull-through affect wind resistance and warranty coverage.

A water-resistant or waterproof layer installed over the roof deck beneath the finished roofing. It provides secondary protection against water intrusion and is required by code in most roof assemblies.

A self-adhering waterproof membrane installed along eaves, valleys, and other vulnerable areas to prevent water backup from ice dams. Code commonly requires it extending at least 24 inches inside the exterior wall line.

A ridge of ice that forms at the eave when snowmelt refreezes, trapping water that can back up under shingles and leak into the building. Attic insulation and ventilation help prevent it.

Metal or other material used to weatherproof joints and penetrations where water is most likely to enter, such as walls, chimneys, skylights, and valleys. Flashing must integrate with the roof covering and underlayment.

L-shaped pieces of flashing installed at the junction of a sloped roof and a sidewall, lapped in shingle fashion so each piece sheds water onto the course below. Required at all roof-to-wall intersections.

Flashing embedded in or attached to a wall, chimney, or other vertical surface that overlaps the base flashing to shed water away from the joint. It completes the weather seal above the roof line.

A metal strip installed along eaves and rakes that directs water away from the fascia and roof deck edge. It also helps protect the underlying wood from rot and is required by most codes.

The purposeful movement of air through an attic using intake vents at the soffit and exhaust vents at the ridge or roof surface to remove heat and moisture and reduce ice damming.

A continuous exhaust vent installed along the roof ridge, typically covered with a shingle-over cap, that allows hot, moist attic air to escape. It must be balanced with adequate soffit intake.

An intake vent installed in the soffit under the eave that allows outside air to enter the attic, balancing exhaust from ridge or roof vents. Blocked soffit vents are a common cause of poor ventilation.

A roof covering made of a fiberglass mat coated with asphalt and mineral granules, available in three-tab and architectural styles. Shingles are the most common steep-slope material in Michigan.

The required number, type, and placement of fasteners for each shingle or panel, specified by the manufacturer and code. Incorrect nailing is a leading cause of wind damage and warranty denial.

Single-ply sheet materials used on low-slope roofs, including EPDM rubber, thermoplastic TPO, and PVC. Seams are adhered, heat-welded, or mechanically fastened, and the material resists ponding water.

A low-slope roof system made of alternating layers of bitumen and reinforcing ply finished with a cap sheet or gravel surfacing. It is durable and common on commercial buildings.

An asphalt-based sheet roofing reinforced with polyester or fiberglass and modified with SBS or APP polymers for flexibility. It is often used on low-slope roofs and as a cap sheet.

Metal roof panels with raised interlocking seams that conceal fasteners and allow thermal movement. Standing seam metal is common on steep-slope roofs and requires special clips and panel attachment.

Components that carry water off a low-slope roof: interior drains connect to downspouts, while scuppers are openings through a parapet wall. Both must be kept clear to prevent ponding.

Standing water on a low-slope roof that does not drain within about 48 hours after rain. Ponding adds structural load and accelerates membrane deterioration; proper slope and drains prevent it.

Official authorization from the local building department to perform roofing work. Permits ensure the work complies with code and trigger inspections; failure to obtain one can invalidate insurance or warranties.

The state-adopted model code based on the International Residential Code that governs one- and two-family dwellings and townhouses in Michigan. Chapter 9 covers roof covering, flashing, and ventilation.

A roof covering classification indicating the highest resistance to external fire exposure in standardized testing. Most asphalt shingles and metal roofs achieve Class A, and local codes may require it.

A written agreement signed by the contractor and homeowner that modifies the original contract scope, price, or schedule. It protects both parties and should be used whenever unforeseen damage or upgrades are discovered.

A legal claim against the property by a contractor, subcontractor, or supplier for unpaid work or materials. Michigan has strict notice and filing deadlines, and a lien waiver can release the claim.

A portion of the contract price, often 5 to 10 percent, withheld by the owner until the project is substantially complete and punch-list items are finished. It protects the owner against incomplete or defective work.

A system or practice used to prevent workers from falling from heights, required by OSHA when working 6 feet or more above a lower level. It includes guardrails, safety nets, and personal fall arrest systems.

A system consisting of a full-body harness, lanyard, and anchor point that stops a fall and limits force on the worker's body. It must be inspected before each use and anchored at required strength.

A barrier of ropes, wires, or chains set up at least 15 feet from an unprotected roof edge to keep workers away from the edge. It is used with a safety monitor on low-slope roofs.

A competent person stationed on the roof to warn workers when they approach an unprotected edge. The safety monitor system is allowed only in limited circumstances, such as roofs 50 feet or less in width.

The rule that a ladder must be set so its base is one foot out for every four feet of height to the support point. This angle keeps the ladder stable and prevents slipping.

A written description in the contract that specifies exactly what the contractor will and will not do, including materials, quantities, and exclusions. A clear scope prevents disputes and unnecessary change orders.