Roofing materials include more than the visible shingles or metal panels. A reliable roof also depends on a sound deck, water-resistant layers, properly installed flashing, ventilation, and compatible fasteners. The exact materials depend on the roof’s design, local building codes, climate, and chosen covering. This guide explains the main supplies for a typical U.S. roof replacement and how to plan quantities before ordering.
Start With the Roof Design and Local Requirements
Before purchasing materials, identify the roof covering, slope, number of planes, valleys, penetrations, and existing deck condition. A simple gable roof uses fewer specialty pieces than a roof with dormers, skylights, hips, or intersecting slopes. The roof’s pitch can also affect which products are allowed; some coverings require a minimum slope or additional underlayment at low slopes.
Local building departments may require permits, inspections, approved products, or specific installation details. Requirements can vary by municipality and may reflect wind, snow, wildfire, or coastal conditions. Check local rules and the product manufacturer’s instructions before buying materials. In areas governed by a homeowners association, exterior material and color approval may also be necessary.
Core Roofing Materials
Roof Decking
The roof deck is the structural surface attached to the rafters or trusses. It is commonly made from plywood or oriented strand board (OSB). Roofing material and underlayment are installed over this surface. During a replacement, the deck should be inspected for rot, delamination, water damage, and inadequate fastening. Damaged or unsuitable sections may need replacement before the new roof goes on.
Decking thickness and attachment depend on the building design and applicable codes. A contractor should confirm what is appropriate rather than assuming that every existing panel is reusable. Any replacement panels need to be compatible with the framing and installed with the required spacing and fasteners.
Underlayment
Underlayment is a water-resistant layer placed over the deck beneath shingles, tiles, or other roof coverings. Common options include asphalt-saturated felt and synthetic underlayment. Product selection depends on the roof covering, slope, climate, and manufacturer requirements. Underlayment provides a secondary layer of protection, but it is not a substitute for proper flashing or a correctly installed roof covering.
Self-adhered ice-and-water barrier is used in vulnerable areas, such as eaves, valleys, and around certain roof penetrations. Local codes may require it in specific locations, particularly where ice dams are a concern. The required width and placement vary, so the installation instructions and local code should guide the plan.
Roof Covering
The roof covering is the exposed material that sheds most rain and snow. Common U.S. options include asphalt shingles, metal panels or shingles, clay or concrete tiles, wood shingles or shakes, slate, and membrane systems for low-slope roofs. Each has different weight, installation methods, maintenance needs, cost, and performance characteristics.
For example, asphalt shingles are widely used on residential pitched roofs, while standing-seam metal is available in a range of profiles and finishes. Tile and slate are heavy and may require structural evaluation. Low-slope roofs commonly use purpose-designed membranes rather than standard shingles. Products are not interchangeable: choose a system rated for the roof’s slope and follow its installation specifications.
Starter Strips, Ridge Caps, and Other Matching Pieces
Many roof-covering systems require dedicated components in addition to the main field material. Asphalt shingle roofs typically use starter strips along eaves and sometimes rakes, plus ridge-cap shingles at hips and ridges. Metal, tile, and other systems have their own edge, ridge, valley, and transition pieces. Using compatible components helps provide a continuous, properly finished system.
Flashing and Water-Management Materials
Flashing directs water away from joints and penetrations, where leaks are more likely to occur. It is commonly made from metal, though some systems use compatible flexible or molded products. Key locations include chimneys, plumbing vents, skylights, walls, valleys, roof edges, and changes in roof slope.
Depending on the design, a roof may need step flashing, counterflashing, valley flashing, drip edge, pipe boots, or specialty flashing kits. Existing flashing should be assessed rather than automatically reused. Flashing materials must be compatible with the roof covering and adjacent materials; some metal combinations can corrode when they contact each other.
Underlayment and flashing work together, but they serve different purposes. Underlayment covers broad deck areas, while flashing manages water at joints and interruptions. A roof can still leak if either is missing, damaged, or installed in the wrong sequence.
Fasteners, Sealants, and Ventilation
Fasteners
Roofing nails, screws, or other approved fasteners secure the covering and related components. The correct type depends on the material, deck, exposure, and manufacturer’s instructions. Nail length, placement, quantity, and corrosion resistance matter. For instance, metal roofing often uses system-specific screws and washers, while shingles generally require approved roofing nails.
Using the wrong fastener or installing it incorrectly can compromise wind resistance, damage the material, or create leak paths. Fasteners should be selected for the product and local exposure conditions, not simply chosen by appearance or price.
Sealants
Roofing sealant may be specified at selected joints, flashing details, or exposed fasteners. It should be compatible with the roof material and intended for exterior roofing use. Sealant is not a replacement for correctly designed flashing, and excessive use can interfere with drainage or make future repairs harder.
Ventilation Components
Many pitched roofs use a balanced ventilation system that brings air in through soffit or eave vents and exhausts it through ridge, roof, or gable vents. The appropriate arrangement depends on the attic design and applicable code. Vent openings must not be blocked by insulation, and adding a new vent type without evaluating the existing system can disrupt airflow.
Ventilation components are not needed in every roof assembly. Some buildings use unvented attic or roof designs that require specific insulation and air-control details. A qualified professional can assess the existing assembly and identify the correct approach.
Roofing Materials by Roof Type
| Roof covering | Typical related materials | Planning considerations |
|---|---|---|
| Asphalt shingles | Underlayment, starter strips, ridge caps, drip edge, flashing, roofing nails, and any required ice barrier | Check minimum slope, shingle exposure, wind rating, and manufacturer fastening pattern. |
| Metal panels or shingles | Underlayment, matching panels, trim, flashing, clips or screws, and closures specified by the system | Confirm panel profile, substrate, movement details, and fastener compatibility. |
| Clay or concrete tile | Underlayment, tiles, battens or attachment hardware where specified, flashing, and ridge or hip components | Evaluate structural capacity and follow the system’s slope and attachment requirements. |
| Wood shingles or shakes | Appropriate underlayment or interlayment, shingles or shakes, flashing, and corrosion-resistant fasteners | Check local fire rules, ventilation details, and maintenance expectations. |
| Low-slope membrane | Specified membrane, insulation or cover board if required, edge details, flashing, and compatible adhesives or fasteners | Use a system designed for the roof’s slope and drainage conditions. |
How to Estimate Roofing Material Quantities
Accurate measurements help prevent shortages and excess orders. Roofers commonly measure roof area in squares: one roofing square equals 100 square feet. The roof area is larger than the home’s footprint because it includes the roof slope, overhangs, and all roof planes.
- Measure each roof plane’s length and width along the sloped surface, then calculate its area.
- Add the areas of all planes to estimate total roof surface.
- Convert square feet to squares by dividing by 100.
- Estimate the covering, underlayment, and accessories using each product’s stated coverage and the roof’s layout.
- Add an appropriate allowance for cuts and waste, then verify quantities with the manufacturer or roofing supplier.
Waste is not a universal percentage. A simple roof may require less than a roof with many hips, valleys, dormers, or complex cuts. Shingles and other products are sold in packages or bundles with coverage that varies by product, so the package label—not a generic bundle assumption—should determine the order.
Flashing, drip edge, ridge materials, and underlayment are often estimated by linear feet, rolls, or specified coverage. Measure the relevant edges and details separately. A supplier or roofing professional can review the takeoff and account for packaging, overlaps, and the selected installation method.
Tools, Safety Gear, and Site Supplies
Though not part of the roof assembly, tools and safety equipment are essential to planning a roofing project. Depending on the system, a crew may need ladders, measuring tools, chalk lines, roofing knives, hammers or nailers, snips, and material-handling equipment. Some installations require specialized tools that should be used only by trained workers.
Fall protection is a critical part of roof work. OSHA’s construction fall-protection rules generally require protection for workers exposed to falls of six feet or more, with specific requirements and exceptions depending on the task and circumstances. Appropriate equipment, training, and a safe work plan are necessary; a ladder alone does not provide fall protection. Homeowners should consider hiring qualified professionals rather than attempting work at height without proper training and equipment.
Other site supplies may include tarps, debris containers, magnetic nail sweepers, and temporary weather protection. A roof can be exposed to rain during tear-off, so the work plan should include a way to protect the home if weather changes.
Common Roofing Material Mistakes
- Buying only the visible roof covering: Underlayment, flashing, edge details, and system-specific components are essential parts of the installation.
- Ignoring roof slope: A material designed for steeper roofs may not be appropriate for a low-slope section.
- Reusing damaged flashing: Old or poorly fitted flashing can undermine a new roof covering.
- Mixing incompatible products: Sealants, metals, fasteners, and roof components should be approved for use together.
- Ordering by house footprint: The footprint does not account for roof pitch, overhangs, or complex planes.
- Overlooking ventilation and drainage: Roof performance depends on managing moisture and directing water to gutters or other drainage points.
- Skipping code and permit checks: Local requirements can affect material choices and installation details.
Roofing Materials Checklist
For a typical pitched-roof replacement, the planning checklist may include the roof covering; replacement decking if needed; underlayment; ice-and-water barrier where required; starter and ridge components; flashing; drip edge; approved fasteners; compatible sealant; and ventilation components if the roof design calls for them. Low-slope roofs and specialty coverings require different, system-specific lists.
The most dependable material list comes from a roof measurement and a system design that accounts for local code, roof slope, weather exposure, and manufacturer instructions. Before ordering, confirm that every component is compatible with the selected covering and that quantities include the roof’s actual geometry and necessary overlaps.