New roof - aluminum valeys or just overlapping shingles

Hi,
I received roof replacement estimate today (Toronto, Canada, 25 year shingles), and guy told me that it is better not to use aluminum values and just make shingles overlap where roof is changing direction. I was told it is better practise as metal valeys tend to change size on heat/cold and makes shingles curl. Can anyone confirm that this is right way to go?
Thank you
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Metal valleys tend to clear themselves of debris better than woven or one-cut valleys. I never had a problem with expansion/contraction messing with the shingles in Michigan. It's more work during the installation for the roofers, all the cuts and such. Maybe this is why they're steering you towards the woven type? Whatever you end up with, see if you can make sure that the roofers cut off the "ears" properly. This is the point left at the top of the valley shingle when it is cut. This helps keep water from catching on the point and moving sideways, instead of down. Tom
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tom wrote:

Yeah, like a shingle is a inflexible, unmoving piece??? :)

That's my guess...

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ttt wrote:

What roof pitch? The shallower the pitch the more I'd stay away from not using valleys, particularly in a cold climate.
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Roof pitch is about 8 1/2 / 12th. SO it is preaty high pitch. I hope this number does make sense :-), I am not roofer. Would metal valley be better for long run for this pitch? Thanks

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ttt wrote:

In the right situation the both will work fine. I like the looks of the weaved shingles myself.

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Joseph Meehan

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Joseph Meehan wrote:

....
In cold clime w/ shallow pitch I think ice buildup in valleys...
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Duane Bozarth wrote:

I have the cold w/snow and ice OK, but the pitch is not shallow. You may be right.
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