Low-Pitched Roof: Re-Roofing Part 3: Installing Asphalt Roof Shingles

By Bruce W. Maki, Editor

This small ranch house had a simple gable roof with no valleys, no hips, no dormers... just two low-pitch planes. The homeowner chose architectural shingles, which cost considerably more than basic three-tab shingles, but which have a longer life and a more interesting, textured appearance.

The first thing we installed was the starter strip, which is just a backing for the first visible row of shingles (it prevents water from getting through to the roof at the gaps between shingles, and at the notches between tabs).

We used pre-cut starter strips, which I had never used before. In the past I have always just trimmed the tabs off a whole shingle. These pre-cut ones save a few bucks when the shingles being installed are higher priced.

We began by installing shingles from the lower corner, working to the right and also working uphill.

We should not have to mention this... but it is not obvious to everyone... the shingles must be arranged so the ends and the tab notches do not lie directly above gaps in the shingle below. If the gaps lined up, water could get directly onto the roof sheathing and then seep in through a nail hole. Note how the shingle on the right (not yet nailed down) is a little longer than the first shingle in the row on the left (which has been nailed down).

In order to accomplish this mis-matching of gaps, we cut progressively larger amounts from the first shingle in each row as we worked up the slope. One row would have nothing cut, the next row would have 6" cut off, then 12" cut off, and so on. The photo shows the scraps cut off from the first shingles in a progression of rows.

Note how the first full shingle overhangs the edge by about 1/8". This makes the water drip away from the fascia (the vertical board at the edge of the roof) and helps reduce deterioration of  the fascia.

The nails are driven in just below the tar strip. The pneumatic nail gun makes quick work out of nailing shingles, but it has some drawbacks.

The main drawback of pneumatic roofing nailers is their inconsistency in nail depth. Sometimes the heads stick up a little and sometimes the heads tear into the shingle. Another frequent problem is that nails sometimes enter the roof at an angle, which makes the head stick up. Protruding nail heads can tear the shingle above them, and it stands to reason that they don't hold as well as properly nailed shingles. In my opinion, hand driving roofing nails gives a superior level of quality... it just takes much longer, perhaps two or three times as long.

The exposure (the amount of the shingle not covered by the shingle above it) of this product was listed on the package as 5-5/8".

The two roofing nail guns we used had an adjustable guide on the bottom.  This allowed us to accurately position the shingle before nailing it.

The same results could have been achieved with an "L"-shaped piece of wood to use as a positioning guide.

It's kind of hard to see in this photo, but the adjustable guide is set against the lower edge of the previous row's shingle (in this case the first row) and the next shingle is rested against the nail gun's contact foot. This creates a uniform exposure every time.

Notice the pattern of shingles as they are applied. This method of starting at a corner and working outwards and upwards can be a good way for two people to apply shingles and not be in each other's way. One person works horizontally and the other works up the diagonal.

Shingling Around A Roof Penetration:

View a detailed article.

A plastic-and-rubber flange was used to seal around penetrations such as this plumbing vent. The lower edge of the flange lies above the shingles, and the upper edge is underneath the shingles. The shingles were cut to fit around the flange's dome.

The shingles adjacent to the flange were adhered with roofing tar, and tar was applied as a sealant where the cut edges of the shingles meet the dome.

Closing In...

At the very top, the shingles were lapped over the peak of the roof.

The shingles were trimmed away from the ridge vent hole.

The ridge cap shingles were attached with two nails each.

The plastic ridge vent was installed with 3" roofing nails. See a detailed article on this ridge vent.

The ridge cap shingles were applied over the ridge vent. There are two narrow bands molded into the plastic indicating where the nails must go.

A dab of tar held down the loose corners of the first shingle.

The completed ridge.

The finished roof. The architectural-grade shingles have a pleasing textured appearance created by the raised layers.

I was surprised that this shingling project only took 5 hours to complete, with 3 people working -  myself, the home owner and a highly experienced contractor, Randy Harrison of Traverse City, Michigan. The 15 man-hours taken to complete this small roofing job just goes to show how quickly roofing work can be accomplished... if the roof is not complicated.

 The homeowner said that the project cost around $1500 for labor and materials. The roof area was about 14' x 42' on each side, or about 1176 square feet.

A small roof like this is well within the grasp of a competent do-it-yourselfer, especially if done one side at a time. It certainly helps to have a helper or two, especially for removing the old shingles and cleaning up the mess around the base of the house. We used two utility trailers for the old shingles and hauled the waste to a dumpster at another job site.

Some Hazards Of Roofing Projects:

Besides the obvious risk of falling off the roof, there are a number of dangers in roofing work:

• Objects can fall off the roof and injure people below. Warn others of the work overhead, and keep children away from the work area.
• Use caution when carrying bundles of shingles up ladders. If the shingle bundles are too heavy, divide the bundle in half (which is the only way I'll carry these extra-heavy shingles up a ladder). There's no need to play He-Man and fall off a ladder, or rip the muscles in your back.
• Keep one hand free when climbing up and down the ladder. An even better way to haul tools and materials is to place them in a bucket and use a rope to lift the bucket.
• Some lumber yards will deliver the shingles to the roof top for an extra charge. This is only practical if the delivery can be timed to the point where the old roof is removed and the tar-paper laid down.
• Use roof jacks on steep roofs such as 6:12 pitch or greater.

Related Articles:

Tearing-Off The Old Shingles

Preparing The Roof For New Shingles

Copyright © 2000, 2005  HammerZone.com

Written November 1, 2000 
Revised January 12, 2005