Thread: How to tell the difference between two layers and a starter strip

Hey guys I'm coming up on my fifth inspection and I have come across three homes where I wasn't sure if the home had two layers of asphalt shingles or was it a starter strip. The first home was built in 2008 in great shape but it looked like it had two layers. There was an asphalt layer under the shingles all the way up the side and all the way across the top. Then today I saw a home wth new shingles on top but underneath at the very lowest part of the home it was two or three layers of asphalt all the way across the bottom. The sides though looked like it only had one layer until I pulled the shingles up really high and saw asphalt covering that Started about two inches in so it couldn't be seen unless you pull the shingles up as high as possible. So my question is how can I tell the difference and what am I doing wrong

The first two pictures are a home built in 1988 and the third picture Image 4062 is the home built in 2008

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Originally Posted by Aaron Scheuerer

Hey guys I'm coming up on my fifth inspection and I have come across three homes where I wasn't sure if the home had two layers of asphalt shingles or was it a starter strip. The first home was built in 2008 in great shape but it looked like it had two layers. There was an asphalt layer under the shingles all the way up the side and all the way across the top. Then today I saw a home wth new shingles on top but underneath at the very lowest part of the home it was two or three layers of asphalt all the way across the bottom. The sides though looked like it only had one layer until I pulled the shingles up really high and saw asphalt covering that Started about two inches in so it couldn't be seen unless you pull the shingles up as high as possible. So my question is how can I tell the difference and what am I doing wrong

The first two pictures are a home built in 1988 and the third picture Image 4062 is the home built in 2008

Aaron,

Some obvious stuff that you probably already know to look for.

One thing that helps is the age of the house.
2008 probably only has the one layer (it's only 9 years old). 1988 might have two, might have one. If the shingles look really old, probably one layer, if they look newer, maybe two.

Look at the general surface. Second layers generally don't lay down as flat as a single layer. If the roof looks "lumpy", probably (not definitely) more than one layer.

Looking at the eaves and gable-ends like you are doing is helpful, but be careful when lifting shingles and don't damage them.

It's ok to say you aren't sure and don't want to damage the shingles.

Originally Posted by Gunnar Alquist

Aaron,

Some obvious stuff that you probably already know to look for.

One thing that helps is the age of the house.
2008 probably only has the one layer (it's only 9 years old). 1988 might have two, might have one. If the shingles look really old, probably one layer, if they look newer, maybe two.

Look at the general surface. Second layers generally don't lay down as flat as a single layer. If the roof looks "lumpy", probably (not definitely) more than one layer.

Looking at the eaves and gable-ends like you are doing is helpful, but be careful when lifting shingles and don't damage them.

It's ok to say you aren't sure and don't want to damage the shingles.

thanks a lot thats really helpful!!!!!!

You might also look in the attic and see how many nails are there. Two layers will usually have a lot more nails.

Originally Posted by Jack Feldmann

You might also look in the attic and see how many nails are there. Two layers will usually have a lot more nails.

wow I like that a lot Definitely didn't think of that one. thanks!!!

Originally Posted by Aaron Scheuerer

wow I like that a lot Definitely didn't think of that one. thanks!!!

From the photos, I would say that the 1988 house has 2 layers. You wouldn't see the tabs on a starter strip.

thanks!!

Originally Posted by Ken Amelin

From the photos, I would say that the 1988 house has 2 layers. You wouldn't see the tabs on a starter strip.

Agreed. Although some around here do use shingles for starter strip, but they will install with tabs up.

- - - Updated - - -

Originally Posted by Aaron Scheuerer

There was an asphalt layer under the shingles all the way up the side and all the way across the top.

If another layer goes up the entire side, then be very suspect of another layer. Starter strips are only at bottom and nobody would place a double layer all the way up.

Another clue if you are able to lift up and view, the lower layer - if a real starter strip - should look about the same age as the top shingles or newer. Remember if a starter was placed at the same time and it has seen zero exposure to elements. If it looks worn, perhaps more so that the top, then something really fishy is going on and consider an old layer.

Originally Posted by Robin A Wells

Agreed. Although some around here do use shingles for starter strip, but they will install with tabs up.

- - - Updated - - -



If another layer goes up the entire side, then be very suspect of another layer. Starter strips are only at bottom and nobody would place a double layer all the way up.

Another clue if you are able to lift up and view, the lower layer - if a real starter strip - should look about the same age as the top shingles or newer. Remember if a starter was placed at the same time and it has seen zero exposure to elements. If it looks worn, perhaps more so that the top, then something really fishy is going on and consider an old layer.

Awesome insight! Thanks!!!

Originally Posted by Jack Feldmann

You might also look in the attic and see how many nails are there. Two layers will usually have a lot more nails.

On a related issue, to determine if the roof has every been replaced I look in the attic for old nail holes. When a roof is stripped the nails will leave scars in the sheathing.

If I'm looking at 3-tab shingles, I look to see if the first course or row of shingles, at the eave, has a 3" exposure instead of the usual (in southeast Michigan) 5".

That will usually happen if a second layer has been nested over the first layer (that is, with the top edge of each new shingle butted against the bottom edge of the old, 1st-layer tabs) because the first full, 12"-deep shingles of the second layer will be nested against the bottom edge of the fourth row of old shingles. The cumulative 15" of exposure in the first 3, old rows will thus be covered by only 12" of new shingles, leaving 3" of 1st row of the second layer exposed to the weather instead of the usual 5".

Also, in our area, the original shingles and drip edge are usually covered with U-shaped drip edge before the second layer is applied, so the presence of U-shaped drip edge usually indicates a second layer of shingles.

You can also use a putty knife and pry up a shingle tab in the middle of the roof. You will either see tar paper, sheathing or old shingles. You can seal down the tab with roofing caulk after you pry it up.
There is a risk of damaging the shingles trying this, so proceed with caution. That said, it is not uncommon to find shingle tabs that lift up easily, since the glue strip never adhered to the shingle above it. Sometimes the shingles up slope from a plumbing vent will lift easily.