How to Install a Roof

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A roof provides protection from the weather and other elements. It also adds to the appearance of a building. Many different materials can be used for roofing, including asphalt shingles, wood shakes, and concrete tiles.

In this post, we’ll take a look at how these roofs are installed.

The first step in most cases is to install underlayment, with three layers most common. The bottom layer is the most important. It is made of asphalt felt paper that is 30-50 mils thick. It is installed with nails every 6-12 inches along the eaves and rakes. The middle layer consists of tar paper that is 15-30 mils thick. The upper layer is also made of tar paper, but it is only 5-20 mils thick.

This underlayment provides a secondary barrier against moisture. If any water does penetrate the lower layer, it will be stopped by the thicker middle layer. The upper layer simply offers additional protection. It becomes less important if you are using shingles that are several inches thick.

The next step is to install the two layers of shingles. The bottom layer has three sub-layers; an asphalt strip, a fiberglass mat, and another asphalt strip. The upper layer only has one asphalt strip at the bottom. It’s important to start with the correct side up on the bottom layer. Shingles are designed with the tab or “hook” at the upper left corner.

If you install them upside down, they will not shed water properly because of this feature. They can also be installed backwards if they are on correctly, but this is harder to do and will lead to problems with wind resistance. The nails are staggered so that they do not go through two layers of shingles. This is important because it helps the roof shed water more effectively.

The last step in installing shingles is to install starter courses at the bottom of the roof. These are usually full-width strips that have both an upper and lower tab on them. The idea is to have a shingle come over the roof edge and be caught by the starter course. This helps keep water from running under the edge of the roof as well as giving you a nice straight line along the bottom.

You can use wood or metal for these courses depending on your property design, but they should always extend beyond both edges of the roof. They also need to be a length that is a multiple of four times the course width, which can be 4, 8, or 12 inches depending on your shingles.

If you have any questions about how to install new roofs on your property, give us a call.

We can provide professional advice and answer any concerns you might have.