Shingles overlapping question


#1

My neighbor was doing a small roofing project and it looked like he was doing something incorrect.

While laying shingles and coming to the last shingle of a row you would normally strike/cut the shingle so it would not overhang. Due the it being a bit colder, on occasion if the shingle was not that much off he would just overlap the last shingle to the previous shingle. So a few inches of shingle ‘A’ would lay under the previous shingle ‘B’ instead of laying flat. The end shingles looked nice and straight by using the factory cut on the outside and you really couldn’t tell a big difference when looking at the work due using a 40 yr shingle in a weatherwood color. But we have disagree about the shingles having any issues down the road.

Is this common practice? would this cause any issues down the road? I told him I would ask the experts and report back as in the spring he has a bigger project! Thanks


#2

Was he laying shingles in the “racking” method (aka “brick style” where a vertical line repeats every other course)?


#3

Ranch - I am not a roofer, but I believe you are referring to staggering the shingles and the answer is yes.

I know that he read the instructions and cut starter shingles. so the first row starter shingle was a full shingle then the next starter row had 6 inches cut off - the next rows starter had 12 inches cut off and so on - then after about 5 shingles up he went back to a full shingle. (the inches is just a guess)

Thanks again!


#4

…Boy oh Boy…I sure hope this is not common practice…
The shingles SHOULD overlap the rake eave approx 3/8"…
The shingles should be set flat on the underlayment and butted end to end with each other NOT overlapped…
I strongly suggest getting some manufacturer’s literature on shingle roof application since this is the field of roofing and therefore the most simple part of roofing who knows what else may not be done right when comes to the more complex edgings, flashings and terminations


#5

This is racking.

Notice the vertical lines lay out like bricks & repeat every other row.

BTW, 95% of the 3T’s in Texas are NOT racked.


#6

are they three tab or demensionals?
i think i know what your talking about,
and that would make them demsionals,
and the top of the run ,would mean the end of the dia
rack, which it started sounding like the roofer
overlaped the last small peace to keep from
havin to cut it.
i can see it, i dont like it,
ive seen it done on a three tab to,
thats even worse.

the same roofer usually does
the one shingle vertically up the valley then
racks them up, so you dont have to cut the valley.
another knucklebrain idea.

gweedo


#7

Ranch,

Although your photo possibly be of one that was installed via the “Racking” method, just the fact that the next couse is offset by 6" and the next course after that is vertically in alignment with the 1st course, does not mean it was racked.

Racking is where the shingle are run straight up verically in a 3 foot and 3 foot 6 inch pattern until it reaches the peak. Then go back down to the bottom eave edge and start over again. It leaves a telltale seam effect every 3 foot on the roof.

Regarding the OP, the shingle should not be overlapped, especially if all of the rest of the field shingles applied were not installed in that manner.

Prior to the advent of architectural style shingles, this was the custom installation method to achieve somewhat of an architectural or laminated final cosmetic appearance. (I know one guy, named Tinner666) from other forums, who installs his 3-tabs in this manner all the time for the additional affect and coverage.)

What should have been done it the neighbor of the OP’s case, is to trim off the interior edge with a knife, if his cutting abilities were such that they would leave a raggedy edge on the exterior overhang. This way, the cut edge would be abutting the next to last shingles edge, prior to being applied, which would not show up visually, unless he cut the edge crooked or tapered.

Ed


#8

Yes, these were dimensional shingles! Sounds like you guys get the idea that the shingles were overlapped and you agree that they should lay flat.

About 98% of the roof was done correctly and a handful of shingles were overlapped! He was doing it because due to the cold weather the shingle were very very difficult to cut and he only did it when he would only have to tuck under an few inches!

I am sure in the future he will do the next project correct after reading this post BUT

Now that you guys agree that this is incorrect! what defects will this cause! Would it be enough to talk him into re shingling these spots!

Thanks again!


#9

No defects, just a cosmetic issue.

Ed


#10

I agree, just a cosmetic issue.

But, on a 40yr dimensional, on a roof, I think it’s just a cosmetic issue to a professional roofer. :smiley:


#11

Well… maybe not cosmetic only if the part that is wedged over / under is only by an inch or so; it can allow water to penetrate sideways.

Same kind of issue for snow or ice penetration as well.


#12

mostly cosmetic.
i dont understand what makes a roofer do it.
its just a few more cuts.

gweedo.


#13

Overlapping shingles as described can make them more susceptible to blow offs, depending upon the type of sealing strip they have.
It is poor roofing practice.
I agree that it is mostly cosmetic, but it is a very good indication of sloppy roofing.

Gweedo:
I never liked them “California” valleys, they encourage small staggers.
A short cut…


#14

Axiom is a roofing god.
his allmighty Ax will join his all mighty cerb,
as roofing.coms elite.


#15

A grand compliment indeed, thank you Gweedo.

You are giving me entirely too much credit though.
I still run into plenty of things I need to think my way through.
I still have plenty to learn.


#16

If it was too cold, and he couldnt cut them good…

I have to ask, was he using a good hook blade? Many newbies try to cut shingles with a straight blade…

If he was using a hook blade, why didnt he try a good pair of large mouth snips?


#17

when its cold like 2 days a year,
i like to lay out a few shingles inside the
garage, run a heater on them.
then i leave all my cut work for last using
those shingles.

gweedo


#18

Cutting shingles is a skill that needs to be developed.
The muscles in your hand, forearm, and wrist need to be trained to do this.

Cold shingles are very hard, you can’t cut through the whole shingle in one pass, and get a good cut.
We change blades frequently, it is not uncommon for me to go through a dozen or more blades on a cold day.


#19

Blades will last longer if you’re cutting them from the back.

Less direct grit contact to wear it out.


#20

How am I supposed to cut a valley or rake from the back?
Blades are a cost of doing business.