Shingle Types
The visible roof covering material:
- 3-Tab Shingle
- Single-layer asphalt shingle with three identical tabs per strip. Cheapest. 15-20 year MA lifespan. Rarely installed today.
- Architectural Shingle (Dimensional / Laminated)
- Multi-layer asphalt shingle with varied tab cuts creating dimensional shadow lines. MA standard. 22-30 year lifespan. Brands: GAF Timberline, CertainTeed Landmark, Owens Corning Duration.
- Designer / Luxury Shingle
- Premium architectural shingle with thicker profile + longer warranty. 30-40 year lifespan. GAF Camelot, GAF Grand Sequoia, CertainTeed Presidential.
- Standing-Seam Metal
- Vertical interlocking metal panels with hidden fasteners. 50+ year lifespan. Galvalume steel, aluminum, copper, zinc options.
- Slate
- Natural quarried stone shingles. 100+ year lifespan. Vermont, Buckingham, Welsh sources. Premium tier.
- Synthetic Slate
- Polymer composite mimicking slate appearance. 50 year lifespan. Brands: Brava, DaVinci.
- Cedar Shake
- Hand-split cedar wood shingles. 30-50 year lifespan with maintenance. Western Red Cedar standard.
Underlayment Layer
The waterproof membrane installed between roof deck and shingles:
- Felt Underlayment (15# / 30#)
- Asphalt-saturated paper. Traditional. 15# thinner, 30# heavier. Being phased out in favor of synthetic.
- Synthetic Underlayment
- Polypropylene or polyethylene fabric. Lighter, more tear-resistant, more weather-tolerant during install. MA standard 2020+. Brands: GAF Tiger Paw, CertainTeed RoofRunner.
- Ice and Water Shield (IWS)
- Self-adhered rubberized asphalt membrane. Sticks directly to roof deck. Required by IRC R905 at eaves extending 24" inside exterior wall line. MA practice extends to 36" for ice dam mitigation. Brands: Grace Ice & Water Shield, Polyglass Polystick.
Flashing Systems
Metal pieces that direct water away from joints, edges, and penetrations:
- Drip Edge
- L-shaped metal at all eaves and rakes. Required by IRC. Aluminum or galvanized steel.
- Step Flashing
- L-shaped pieces installed at roof-to-wall junctions. Each piece overlaps the previous shingle.
- Counter Flashing
- Cap flashing installed over step flashing at chimneys. Tucked into masonry mortar joint or covered by siding.
- Apron Flashing
- Single-piece flashing at the bottom of a chimney or wall-to-roof junction.
- Cricket / Saddle Flashing
- Sloped framing structure installed behind chimneys to divert water around the chimney.
- Vent Boot / Pipe Flashing
- Rubber + metal collar around plumbing vent pipes or other roof penetrations.
Ventilation Components
Attic ventilation system maintaining proper airflow:
- Soffit Vent
- Continuous or individual vents in soffit (eave underside). Air entry point.
- Ridge Vent
- Continuous vent along peak of roof. Air exit point.
- Gable Vent
- Vent in gable end wall. Older ventilation method, less effective than soffit-to-ridge.
- Power Vent
- Electric fan-driven vent. Used when passive ventilation insufficient. Usually unnecessary in MA.
- NFA (Net Free Area)
- Total area of vent openings (excluding screen + grating). Code requires 1:300 NFA ratio of attic floor area for soffit + ridge combined.
Structural + Other Key Terms
Additional roofing vocabulary:
- Deck (Sheathing)
- Plywood or OSB structural panel installed over rafters/trusses. The roof's structural surface. 7/16" OSB or 5/8" plywood standard.
- Rafter
- Sloped framing member supporting the roof deck. Sized per snow load + span.
- Truss
- Pre-fabricated triangulated framing assembly. Replaces rafters in modern construction.
- Pitch / Slope
- Vertical rise per 12 inches horizontal run. 6:12 = 6 inches rise per foot.
- Square (roofing measurement)
- 100 square feet of roof surface. Used for material quantities (1 square = enough shingles to cover 100 sq ft).
- Cricket
- Sloped framing structure behind chimneys; same as saddle.
- Valley
- Internal angle where two roof slopes meet. Open valley = visible metal valley flashing. Closed valley = shingles woven across.
- Tear-Off
- Removal of existing roofing material before new install. Standard MA practice (vs layovers).
Frequently Asked Questions
What's the difference between architectural and 3-tab shingles?
Architectural shingles are multi-layer laminated with varied tab cuts creating dimensional appearance. 3-tab are single-layer with uniform tabs. Architectural lasts 22-30 years; 3-tab 15-20 years. MA standard is architectural; 3-tab rarely installed today.
Is ice and water shield required in Massachusetts?
Required by IRC R905.1.2 at all eaves extending 24 inches inside the exterior wall line. MA practice extends to 36 inches for ice dam mitigation. Premium membrane (Grace Ice & Water Shield, Polyglass Polystick) recommended.
How much ridge vent and soffit vent does my MA home need?
Per IRC R806: 1:300 NFA ratio of attic floor area, split equally between soffit (intake) + ridge (exhaust). 1,500 sq ft attic = 5 sq ft total NFA = 2.5 sq ft soffit + 2.5 sq ft ridge. Properly sized continuous soffit + ridge vents typically meet this without separate calculation.
What's the difference between drip edge and step flashing?
Drip edge: L-shaped metal at all eaves and rakes (perimeter of roof). Directs water off the edge. Step flashing: L-shaped pieces at roof-to-wall junctions (chimneys, dormers, walls). Each step piece overlaps the previous shingle.
Why is OSB used vs plywood for roof decking?
OSB (oriented strand board) is more cost-effective than plywood and meets identical structural requirements. Both are code-compliant. Pro Build typically uses 7/16" OSB on standard installs; 5/8" CDX plywood on premium installs.
What's a 'square' in roofing pricing?
100 square feet of roof surface. A 28-square roof = 2,800 sq ft. Material quantities + per-square pricing reference this standard. Helpful when comparing contractor estimates: divide total cost by squares to get per-square pricing.
References & Sources
- International Residential Code R905 — Roof Coverings. https://codes.iccsafe.org/content/IRC2021/chapter-9-roof-assemblies
- ASTM D7158 — Standard Test Method for Wind Resistance of Asphalt Shingles. https://www.astm.org/d7158-22.html
- GAF Roofing Materials. https://www.gaf.com/
