A Good Flat Re Roofing Job

This shows a good re roofing job with modified bituminous roof covering.

Partial of Re Roofing Job

How to Spot a Good Overall Job

It is important to learn how to evaluate a residential flat roof. Here is what is important to note: The above photo shows re roofing, which means the new roof covering was laid over an existing roof. This means that the job was not a “tear off”, where all the old roofing is removed down to the wood deck. The roof covering is rolled out in sheets. The seams are the thin vertical lines.

To the left is the edge of the roof. To the bottom is the neighbor’s house. ( This is typical for Philadelphia town houses.) The sheets are evenly laid down, and the seams are even. There is a slight undulation to the roof surface, most visible in the right side of the photo.  This is the old roof telegraphing through the new roof covering. The new roof covering is pretty smooth because the old roof, which was covered, was in decent shape, and the roofers took the time to correct any gouges or defects in the old roof.

At the left of the photo, you can see that roofing cement has been neatly applied by hand to the edge seam between the new roof covering and the metal drip edge. This is the proper way to do this. At the bottom, the alternating light and dark on top of the parapet wall, (the party wall dividing the two houses,) the neighbors had their roof done after the roof in the upper part of the photo.  Cutoffs were used, which created an extra seam that is visible in the shadows of the neighbor’s roof. The is not as desirable as rolling a full sheet up onto the parapet wall, as was done.

Roof details should be clean

Detail of the Roof Outlet Box

How to Evaluate Roof Details

One of the most important detail is the outlet box. It is important because all the water on the roof goes through it. The roof outlet box is a formed piece of sheet mental with a round “drop” that connects to the rain leader, commonly known as the downspout. Here the outlet box is clean, and the hand-applied roofing cement is neat. The new roof covering on the wall to the right shows a slight amount of wrinkling. In a good job, there should be a minimal amount of wrinkling, and it should only occur in tight corners such as shown here. The field of the roof should have almost no wrinkles. 

If you to look at the roof overall and some important details, you are on your way to learning how to evaluate a residential flat roof.

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