Replacing Your Roof: A Comprehensive Guide

A new roof is likely one of the biggest investments you’ll make as a homeowner. Though this project can be intimidating, getting the job done right really boils down to two things: choosing the right roofing materials and working with a reputable contractor. In this guide, we’ll cover everything you need to know about selecting and installing a new roof. Check out our guide on new roof costs for more information on pricing.

Understanding Your Roof System

While the shingles are all you see, your roof is actually a system with many parts that work together to keep your house dry and comfortable. The focus is not just on keeping the weather out but also on letting in fresh air to prevent a buildup of heat and humidity in the attic. Here are the basic parts involved in a shingle roof replacement, starting with the innermost layer.

• Roof deck: The deck is the foundation of your roof, usually made of plywood or oriented strand board (OSB). If you choose a full tear-off replacement, the contractor will strip your roof down to this layer.
• Ice and water shield: This is a self-adhesive membrane applied along the roof’s perimeter from the eaves up. It should reach 3 feet beyond the inside of the wall and cover any valleys to prevent ice dams and wind-driven rain from reaching the decking.
• Underlayment: Underlayment is a water-resistant barrier installed over the roof deck. This synthetic layer covers the entire roof deck and is the second line of defense against leaks, after the shingles.
• Starter shingles: These are a narrow row of asphalt roofing nailed to the perimeter of the roof. A bead of adhesive on top grips the underside of the first course of shingles, keeping them in place during high winds.
• Shingles: Shingles are the visible outer layer of your roof. Applied from the eaves up toward the ridge, shingles are staggered to prevent water from seeping in.
• Ridge vent: A ridge vent is installed along the peak (or ridge) of a sloped roof. Roofers use a circular saw to cut a long slot along the roof ridge, then cover it with a plastic flap (as shown) or a flexible vinyl matrix. Openings along the sides allow air out of the attic, cooling the space and lowering your air-conditioning bill.
• Ridge caps: Ridge caps are square sections installed over the ridge vent. These caps straddle vulnerable parts where two planes of the roof meet and are designed to blend in with the rest of the shingles.

How Long Should Your Roof Last?

The lifespan of a roof varies depending on the material used, the quality of installation, climate conditions, and ongoing maintenance. However, here’s a general estimate for common roofing materials.

One way to gauge your roof’s potential lifespan is to look at the manufacturer’s warranty. Most asphalt shingle manufacturers offer warranties ranging from 20–30 years, while some premium options boast 50-year or even “lifetime” warranties. Keep in mind that these are typically limited warranties, meaning they may only cover certain defects or have prorated coverage over time.

What Do Roof Warranties Cover?

Your new roof will likely come with two types of warranties: a manufacturer’s warranty and a workmanship warranty. A manufacturer’s warranty covers defects in the roofing materials themselves, while a workmanship warranty covers the quality of the installation. Be sure to read and understand both warranties thoroughly. Pay attention to what’s covered, what’s excluded, and any requirements for maintaining coverage (e.g., regular inspections).

Three-tab shingles usually carry a 20-, 25-, or 30-year warranty against manufacturing defects; laminated versions carry a “lifetime” warranty that typically covers them for as long as you own the house, or a maximum of 40 to 50 years. If the shingles fail at any point during that timeframe, expect a check for a prorated amount.

Some manufacturers offer more expensive “total coverage” warranties. If the roof fails within a set timeframe—usually 25 years—the package covers the cost of new shingles and the labor to reroof. 

If you’re buying a house with a new roof, don’t assume you’re covered just because the roof was recently installed. Ask for the name of the manufacturer, notify the company of the change in ownership, and find out if the warranty transfers to you.

Choosing the Right Roofing Material

The roofing material you choose significantly impacts your home’s appearance, energy efficiency, durability, and overall cost. Here’s a brief look at some of the most popular options:

• Asphalt shingles: The most common choice in America, known for affordability and versatility.
• Metal roofing: Increasingly popular for its longevity, energy efficiency, and modern look.
• Wood shakes or shingles: Offer a classic, natural look but require more maintenance.
• Clay or concrete tiles: Extremely durable and fire-resistant, ideal for warmer climates.
• Slate: A high-end, long-lasting option with a unique appearance.

Factors To Consider

Since asphalt shingles are the most popular choice for homeowners, let’s take a closer look at the different factors to consider as you shop for this specific type of product. Remember that the more you’re willing to spend, the more colors and shapes you’ll have to choose from.

Shingle Colors

Shingle color can dramatically impact your home’s curb appeal. Choose a color that complements your home’s exterior and fits your neighborhood’s aesthetic. Consider lighter colors for energy efficiency in warmer climates.

Shingle Grade

Shingles come in different grades, from standard three-tab shingles to architectural or dimensional shingles with a more textured appearance. Higher-grade shingles typically offer greater durability and wind resistance. 

Nearly all shingles start as fiberglass mats soaked with water-resistant asphalt. The top coat is a layer of igneous rock granules, wrapped in a ceramic-pigment coating that protects the asphalt from UV rays. Made in one consistent thickness, these shingles are usually 12 by 36 inches with three to five tabs, or segments—all with the same rectangular shape. Three-tab shingles are the most affordable option and give your roof a clean, uniform look.

Architectural shingles have two or more layers with three-dimensional tabs of varying sizes. These shingles are usually the same size as the basic three-tab design but can weigh up to 50 percent more, which may increase durability and come with a longer warranty. They are more expensive than three-tab shingles, but they come in a wider range of colors and designs. Some are even designed to mimic the look of wood or slate.

Shingle Shape

Shingles are available in various shapes, including the traditional three-tab style, architectural shingles with a staggered design, and designer shingles that mimic the look of wood shakes or slate. You can find pictures of a few unique shapes at the bottom of this article—including zig-zags, diamonds, and scallops.

Energy Efficiency

If you live in a warm climate, we recommend investing in “cool roof” shingles that reflect more sunlight and absorb less heat. The dark granules on laminated asphalt shingles absorb the sun’s radiation and push heat into the building, which explains why an attic can be 50–85 degrees warmer than the outside temperature on a hot summer day. Cool-roof shingles help lower that difference to as little as 5–10 degrees by using granules coated with a highly reflective pigment. 

The Cool Roof Rating Council tests and rates different roofing products after three years of outdoor exposure in three different locations across the U.S. When comparing these products, look for the highest numbers in solar reflectance and thermal emittance. Expect to pay anywhere from 10% to 50% more for cool-roof shingles.

The Roof Replacement Process

Replacing your roof is a significant undertaking, but understanding the process can help you prepare and make informed decisions. There are two primary methods of roof replacement: roof overlay (or re-roofing) and roof tear-off (or full replacement).

The specific steps involved in each method depend on your roof type and chosen materials. However, the general process typically includes the following:

• Inspection and preparation: Assessing the roof’s condition, obtaining permits, and protecting the surrounding area.
• Removal of old roofing (tear-off only): Carefully removing existing shingles, underlayment, and flashing.
• Inspection and repair (tear-off only): Inspecting the roof deck for damage and making any necessary repairs.
• Installation of new roofing materials: Installing underlayment, flashing, and the new roof covering according to manufacturer specifications.
• Cleanup and final inspection: Removing debris, cleaning up the work area, and conducting a final inspection to ensure the quality of the installation.

Choosing the right method for your roof replacement depends on various factors, including the condition of your existing roof, budget, and long-term goals.

They use the same shingles, but these two installation methods are very different.

Overlay: Putting on a Second Layer

Most building codes allow for two layers of asphalt shingles on a house, so stripping off everything down to the plywood sheathing may not be your only choice. If your roof is in good shape but has some damage to one side from a downed tree or has lost shingles in a wind storm, an overlay is worth considering.

Nailing new shingles over existing ones requires less labor, making it less expensive and faster in the short term. However, this approach is not suitable for all roofs. Adding a second layer of shingles will make your roof heavier, and you won’t have a chance to assess the roof deck for signs of water damage.

Tear-Off: Stripping Away the Old Roof

This method is more expensive because of the additional labor and materials, but peeling off the old roof down to the sheathing is your only option if you already have two layers. This Old House general contractor Tom Silva prefers this route even when the roof is just a single layer so he can find the source of any water damage, upgrade the flashing, and install shingles so they lie flatter.

Roof Replacement Costs and Budgeting

The cost of replacing your roof can vary significantly depending on several factors.

• Roof size and complexity: Larger or more complex roofs with multiple slopes, dormers, chimneys, or skylights will generally cost more to replace than smaller, simpler roofs.
• Roofing material: The type of material you choose greatly influences the cost. Asphalt shingles are typically the most affordable, while metal, tile, or slate roofs can be significantly more expensive.
• Labor costs: Labor rates vary depending on your location and the complexity of the job.
• Removal of old roofing: If your existing roof needs to be torn off and disposed of, this will add to the overall cost.
• Additional upgrades: Opting for additional upgrades like new flashing, ventilation systems, or insulation will increase the total project cost.
• Permits and inspections: Depending on local regulations, you may need to obtain permits and schedule inspections, which can add to the expenses.

While it’s difficult to provide an exact cost estimate without specific details about your roof, it’s helpful to have a general idea of what to expect. Replacing a roof costs about $10,000 on average, with most homeowners paying between $5,855 and $13,116, according to contractor data compiled by Angi. 

We recommend getting quotes from at least three roofing contractors in your area to get a more accurate estimate. Here’s what these quotes should include:

• Materials (55%–65%): A full tear-off roof replacement requires many unseen parts, like underlayments and starter strips, but materials only account for about 55% of the cost. In an overlay, the shingles are the main material and account for more of the cost of a shingle roof—about 65%.
• Labor (25%–35%): Stripping off a roof is labor-intensive, and complicated rooflines can increase the cost.
• Disposal (5%): This line item covers your contractor’s cost for renting a dumpster and disposing of debris.
• Job site extras (5%): This can include fees for craning bundles of shingles up to the roof and renting scaffolding or portable toilets.

Hiring a Roofing Contractor

Although some homeowners may have the skills to tackle a roof replacement, we recommend hiring an experienced roofing contractor due to the risks and complexity involved. Here are some tips to help you find a reliable professional and ensure a smooth process:

• Get multiple estimates: Don’t settle for the first contractor you find. Get at least three estimates from reputable companies to compare prices and services.
• Check credentials: Verify that the contractor is licensed, insured, and bonded. Ask for references and check online reviews to gauge their reputation and past performance.
• Ask the right questions: Inquire about their experience, the materials they use, their warranty, and their timeline for completing the project.
• Get everything in writing: Make sure you have a detailed written contract that outlines the scope of work, materials, timeline, payment schedule, and warranty information.

You should also take a few proactive steps to protect your property during the process.

• Prevent driveway dents: Ask the delivery driver to place wood blocks under the wheels of the debris container to distribute the weight and protect your driveway.
• Do a perimeter check: Before work begins, have the contractor move outdoor furniture and cover any valuable plants. After the project, ask them to use a magnetic sweeper to pick up stray nails.
• Save leftover shingles: Keep a bundle or two of new shingles for future repairs. This ensures you have matching materials for any necessary patch jobs.

Other Considerations When Redoing Your Roof

Consider bundling your roofing project with other home improvements, such as adding attic insulation or replacing your siding. Here are a few suggestions.

Ventilation

Before ridge vents became standard, cupolas were used to cool houses and barns. Fitted with louvers, or electronically controlled windows, they help draw cool air in through soffits or open windows, then vent warm air from the top of the building. If this is something you’re interested in, it makes sense to install as you’re replacing your roof. For active ventilation, consider installing an attic fan.

Solar Panels

If you’re interested in renewable energy and reducing your electricity bills, a roof replacement is an ideal opportunity to install solar panels. Combining the projects ensures your new roof is designed to accommodate the solar panels, maximizing energy efficiency and long-term savings.

Skylights

To install a skylight, the roofers cut the sheathing and frame an opening, then cut a corresponding hole in the ceiling. A light shaft, built like walls, then joins the two to bring daylight into the house.

New Gutters

Reroofing estimates often include the cost of new gutters because your existing troughs have to come off. Upgrading to copper gutters costs more than twice as much as vinyl or aluminum, but they add style (and function) that should last a lifetime.

Our Conclusion

Replacing your roof is a major investment, but one that can significantly enhance your home’s protection, energy efficiency, and curb appeal. By understanding the lifespan of different roofing materials, choosing the right option for your needs, and hiring a reputable contractor, you can ensure a successful roof replacement project. Don’t hesitate to ask questions, get multiple estimates, and prioritize quality materials and workmanship.