Whether you’ve decided to replace your own roof or you’re going to hire a professional, you need to know what the roof installation process entails.

As a DIYer, understanding the steps to replace a roof will prepare you for the process. And if you’re working with a roofing contractor, you’ll be able to assess estimates and understand the cost breakdowns.

For the most common types of roofs – asphalt shingles and metal – installation follows a similar pattern.

Here’s a basic overview of what happens before and during a new roof installation.

Remove the Old Roof

Storm damage is a leading cause of roof replacement. While some contractors may tell you they can install your new roof over your old one, that’s rarely the right way to go. Instead, plan on removing the entire old roof.

When looking at your roof, you’ll see the top roofing material, like shingles or metal. But, there’s also a layer of felt under the surface. Under the felt is a layer of wood.

You’ll need to remove:

Roofing material (shingles or metal)FeltDamaged or rotting sections of plywood

Evaluate What’s Left

Once you’ve removed the roofing material and felt, it’s time to evaluate the sheathing underneath. While some pieces of wood may be in fine shape, this is an excellent opportunity to find potential problem areas.

With the entire roof exposed, examine every piece of wood for water damage, holes, and other signs of wear. In an ideal situation, this will be the last time you see these pieces of wood for decades.

Replacing the Felt

Once you’ve replaced any damaged sheathing, the installation process can begin. First, you’ll need to install a new felt which serves as a moisture barrier between your home and the outside. Felt is an underlayment that comes in rolls and ranges from $165 to $250 per roll, depending on the quality.

Felt is simple to roll out and attach to the sheathing on your home. Experts recommend placing roofing tacks at four-inch intervals in the felt underlayment to ensure no gaps between it and the sheathing.

It’s a good idea to invest in a high-quality underlayment. While you can save money by buying a lower-grade felt, doing so may lead to roofing problems in the future.

Protecting the Roof

There are multiple items you must install after the underlayment. Even if you live in an area that doesn’t suffer extreme winters, you should install an ice and water barrier. This thick material runs along the roof’s perimeter and protects against ice buildup and pooling water.

Once the ice and water barrier is installed, you can install a drip edge. A drip edge runs along the eaves of your home and ensures that water drains away from your house.

Installing the New Roofing Finish

Once the sheathing and the underlayment are down, installing the new roofing finish can begin. In some areas, metal roofs are more common than shingles—these large pieces of roofing tin range in cost from $10 to $18.50 per square foot. In many cases, the companies selling roofing tin will discount the price if you buy a large amount.

One square of shingles covers 100 square feet of your roof. There are different calibers of shingles on the market, leading to a large price discrepancy. On average, the cost of shingles is somewhere between $170 and $400 per square.

Installing the new roof finish is the longest part of the process, and it takes longer to install shingles than it does to install a metal roof.

Final Thoughts

The process of removing an old roof and installing a new one is time-consuming. During the process, it’s a good idea to have high-grade tarps on hand to keep your home covered.

If you live in a large home, plan on the roof-replacement process taking several days. While it’s possible to replace the roof on a small house or a mobile home in a single day, don’t rush the job.