# Metric Architectural Shingles



## m_ridzon (Sep 29, 2017)

The last time I laid a roof many years ago, was with the traditional 3-tab 36" by 12" shingles. Yesterday, I laid a new roof and had my first exposure to the architectural shingles. I'm an engineer and so I started looking closely at these architectural shingles. It turns out that they measure 39.3" long by 13.1" tall. Oddly enough, this converts to 1 meter by 1/3 meter. I doubt this is coincidence. I then found it humorous to read the roofing instructions inside the package, giving English cutting dimensions on these metric shingles. So my question is...when and why did the roofing industry decide to embrace and promote metric shingles while the rest of the construction industry continues to use English units (at least in the USA). What's the history behind this decision to switch and why?

Thanks in advance!


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## roofermann (Nov 18, 2013)

I don't know, but went ahead and asked in another forum, you can follow here; http://talk.roofing.com/t/why-did-everybody-switch-from-standard-sized-shingles-to-metric/20322


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## Oso954 (Jun 23, 2012)

Unless you are laying metric over “Imperial” shingles (I wouldn’t) what difference does it make ?

It’s not like you have to use metric nails and hammers.


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## m_ridzon (Sep 29, 2017)

Oso954 said:


> Unless you are laying metric over “Imperial” shingles (I wouldn’t) what difference does it make ?
> 
> It’s not like you have to use metric nails and hammers.


Of course, it doesn't make a difference. I get that. It was just a question to educate myself about how the roofing industry got here, despite the remainder of the construction industry in the USA sticking with Imperial measurements. The architectural shingle industry is the black sheep and I was just curious why.


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## Nealtw (Jun 22, 2017)

m_ridzon said:


> Of course, it doesn't make a difference. I get that. It was just a question to educate myself about how the roofing industry got here, despite the remainder of the construction industry in the USA sticking with Imperial measurements. The architectural shingle industry is the black sheep and I was just curious why.


 Maybe the question would be what machinery they are using at the factory and where was it made.


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## SPS-1 (Oct 21, 2008)

You peeked my interest, so I did a search, and found that asphalt roofing shingles started to go metric a little before 1980 (there was a technical paper written about acceptance of the new size in 1980). A little surprising, but if you work it out, the metric size is actually 19% more area than the 12" x 36" size. Question for Rooferman if that makes putting down metric sized shingles more efficient (i.e cheaper) ? 


The US is about the last country to go metric, and the US government has been trying to push conversion starting about 1975 (i.e. the Metric Conversion Act of 1975)


Not sure if this link will work, to free Google E-book on subject: https://books.google.ca/books?id=OT...ge&q=roof shingle size metric vs inch&f=false 


If not Google "e-book Metric Conversion in the Construction Industries--technical ..., Volume 13"


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## aribert (Apr 7, 2012)

Oso954 said:


> Unless you are laying metric over “Imperial” shingles (I wouldn’t) what difference does it make ?
> 
> It’s not like you have to use metric nails and hammers.



Not intending to hijack the thread - I am about to reroof a garage (doing the full tear-off on the house). I knew the new shingles were metric. I never thought of dealing with the 12 x 36 shingles currently on the garage roof (if memory is correct the exposed dimension on the 12 x 36 is about 5 inches vs the 5 5/8 on the metric shingles that I am using (Landmark Pro).


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## roofermann (Nov 18, 2013)

A bit quicker, fewer shingles to cover the same area.


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## m_ridzon (Sep 29, 2017)

aribert said:


> Not intending to hijack the thread - I am about to reroof a garage (doing the full tear-off on the house). I knew the new shingles were metric. I never thought of dealing with the 12 x 36 shingles currently on the garage roof (if memory is correct the exposed dimension on the 12 x 36 is about 5 inches vs the 5 5/8 on the metric shingles that I am using (Landmark Pro).


Yes, the exposed dimension on the old traditional 12" x 36" shingles is 5" while the metric architectural shingles have 5-5/8" exposure. It again illustrates the oddity that I highlighted with my initial post. That is, they are metric shingles, but all the cutting and sizing dimensions for their installation are still published with English dimensions. I find it very humorous that the shingle industry is trying to embrace both simultaneously. 

Be sure to read the packaging on the architectural shingle bundle. It was very helpful for me (not being an expert roofer) to know how to trim each course and lay them properly. Following those instructions, it went super smooth. 

Also note that architectural shingles still need a starter course like the older traditional shingles. I think you can buy "special" architectural "starter" shingles, but I'm told they are costly. The alternative is to buy a bundle(s) of traditional 12 x 36 shingles, cut off their tabs, flip them upside down, and use them for the starter course like the old timers did. This is what I did and is a much cheaper alternative from my understanding. The old traditional 3-tab shingles also work great and are a cheaper alternative for the cap/peak (as long as they are color coordinated to the architectural shingles); again from my understanding, you can buy special architectural "cap" shingles but they are costly.


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## m_ridzon (Sep 29, 2017)

SPS-1 said:


> You peeked my interest, so I did a search, and found that asphalt roofing shingles started to go metric a little before 1980
> 
> The US is about the last country to go metric, and the US government has been trying to push conversion starting about 1975 (i.e. the Metric Conversion Act of 1975)


Thanks for the helpful feedback. 1980? Hmm. I guess I find it odd that the remainder of the US construction industry is firmly sticking with English units while the shingles are pioneering a different direction. 

I'm an engineer and have worked extensively with English and metric units on various projects. I find it interesting that metric is noted as superior because of its simplicity versus English. I have not found this to be completely true with all the different physics I've been exposed to and had to calculate in the metric system. Metric has its own shortcomings and issues too. But that's another discussion for another day.:wink2:

Thanks again!


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## craig11152 (Jun 20, 2015)

aribert said:


> Not intending to hijack the thread - I am about to reroof a garage (doing the full tear-off on the house). I knew the new shingles were metric. I never thought of dealing with the 12 x 36 shingles currently on the garage roof (if memory is correct the exposed dimension on the 12 x 36 is about 5 inches vs the 5 5/8 on the metric shingles that I am using (Landmark Pro).


Am I to understand you are putting a second layer on the garage? 
If so I highly recommend butting up to the old shingles @ 5" and buying the extra bundle or 2 it might take for the reduced exposure. 
IMO the single most important thing on a second layer is to butt the top edge of the second layer to the bottom edge of the first layer. 
In doing this you will cut off about 2" of the top of the first course so it drops in place properly and that first course will only show about 3" of exposure. After that you just "butt and run" up the roof at 5". That will get you a roof that lays as flat as a tear off would have.


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## craig11152 (Jun 20, 2015)

I started shingling in Ann Arbor in 1979. Back then everything in my neck of the woods was "standard" 3 -tabs except for metric 3 tab IKO's that came from Canada. The first laminated shingles I remember were from Certainteed and they too were "standard" size. The term "standard" back then referred to a 36"x12" shingle with a 5" exposure. It made sense because a metric shingle was the odd size. I can't say I remember exactly when the transition began in my area. 
I imagine from a manufacturing standpoint you can crank out more metric squares per hour in production because you have fewer shingles per square.


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## NickTheGreat (Jul 25, 2014)

Interesting. I probably haven't roofed a house since they went metric (been a while). 

I agree it's likely not important, but an interesting observation nonetheless.


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