May 20, 2021

Roof Inspection at Dowell Roofing

In this article, I want to go over how I carry out a roof inspection on a residential shingle roof. What makes a good roof? How do you know it is quality work? How much life expectancy remains? Can the roof be repaired or is replacement warranted? There are a lot of things to consider.

I have been installing residential roofing since I was fourteen. As I write, almost 30 years of roofing experience informs me. So as I look around a roof, I am seeing far more detail than I can express here, but it’s a good start. Come follow me up the ladder…

During a Roof Inspection


loped roof, Dowell Roofing, Murfreesboro Roofers


The first thing I look for is just above the gutter. I lift the lowest course of shingles to determine the type of decking (plywood, OSB, or one-by boards). Each type has its strengths and weaknesses, but the purpose of the roof inspection at this point is to make notation for future work. Also, I can typically see the type of underlayment (felt, synthetic, Ice & Water, Shield, etc.). In addition, I am looking to see if the overhang of the shingles is sufficient (we do 1” past any metal edge, 1 ½” past wood). Lastly, I note the presence or absence of drip edge. We’re finally ready to step onto the roof.

General Condition

Of primary concern is the general condition. Has this roof disintegrated from 30 years of sun and weathering or are the shingles relatively new; tightly granulated, smooth, with minimal color fading? Every roof falls between these extremes. A quality shingle merely progresses more slowly to disintegration. An inferior shingle more quickly. In addition to the general condition, I am looking at the type of shingle. If they sell the shingle in the Middle Tennessee area, I have used it even if only when doing repair. The common manufacturers and their brands are known by an experienced installer and repairman. Product quality will have an impact on roof life expectancy. Even so, a cheap shingle installed well can still last 20 years or more, with minimal maintenance.


After assessing the condition and type of roofing material, workmanship is my concern when conducting a roof inspection. My repairmen are very experienced journeyman or outright master roofers. My crews always have a foreman and experienced installers. Other companies are not so blessed. I can tell within minutes what type of crew installed the roofing.

Shingle Alignment

Looking left and right along the roof’s length allows you to ascertain the “straightness” of each course. If the shingles appear to “roll up and down” like a roller coaster, then you are dealing with amateurs. It’s possible you’re on a poorly framed or very old roof that itself “rolls” making straight courses impossible, but this is not typical.

Shingle Offset

Next, I look at the shingle offsets. Each course should stagger around 6” left or right to the proper course. I especially inspect the stagger up the valleys and along the wall intersections. A crews’ top installers will often install valleys, along walls, chimneys, skylights, and air vents. I can look at their offsetting and determine the crew’s experience level.

How the Shingles Were Cut

Next, I might look at “the cuts”. Are the valley overlays cut back straight and cleanly? Do the rakes have the proper overhang and look professional? Are the vents and boots cut back with at least ¼” clearance? However, most critical to a quality roof is nail placement.

Nail Placement

worker on roof putting shingles down, Dowell Roofing, Murfreesboro Roofers

Nothing is more critical, and yet more commonly butchered than nail placement. I have seen brand new roofs literally slide off due to improper placement. Much of the “blown off shingles” are simply shingles that were shot through and slid out of place. Often, the nails are shot too high and the lower half of the shingles pulls apart. Too much air pressure, especially when the roof is hot, in conjunction with installers that only care about money and who don’t expect their work to undergo a roof inspection, equals a lousy roof. I see examples every week.

A tremendous amount of repair work, even insurance claims, originate from nail placement. I learned to roof before roofing guns were commonly used, driving the nails by hand. Through this, you learn what a good nail “feels” and looks like. Many roofers today have no idea. They learned from a lousy roofer and they think lousy roofing is how roofing is done. Nails can not only be shot too deeply or too high above the nail line, they can also be shot not deeply enough, which can lead to raised shingles or even leaks. They can be shot in water gaps, too close to the center of valleys, or even not at all! The lowly nail can be the difference between excellence in roofing or a disaster in the making.

With Dowell Roofing, you can bet you are getting not only the best quality products, but all the years of experience the company has to offer. We always finish a job as if we were working on our own homes, because that’s what you deserve.

Choose excellence. Choose Dowell Roofing.


Residential Roofing Solutions Murfreesboro TN

We look forward to assisting you with all of your roofing needs.

To schedule your roofing inspection and consultation, please call Joseph Dowell at