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ct123123 12-08-2018 08:25 PM

Reasons to build roofs over 4/12 pitch? (more dangerous)
What are any good reasons to build steeper than 4/12?

6/12 is somewhat ok but one loose shingle and forget it. Don't get me wrong though, a loose shingle on a 4/12 is still very unsafe, all it takes is for the few nails to be oversunk just a tad, which you wouldn't see, and it's like putting one foot and all your weight on a piece of cardboard that can shred downward through the few oversunk nails holding it - but the steeper the roof the more likely this can happen. That's all beside the point of slippery conditions caused by old asphalt granules on the roof, moss, etc etc. But 4/12 the least steep is like a night and day difference. You can barely put tools on a 6/12 without needing a tied off bucket or something either. Just walking on a 6 or 9/12 is dangerous.

The 'reason' or benefit for a steep roof is that it sheds water quicker and is less prone to wind lifting shingles BUT it's only a minor difference compared to a 4/12. 4/12 will last just about as long AND any time the home owner needs something done on the roof, gutters cleaned, attic fan etc, etc, even a frisbee stuck on the roof they have to call a roofer willing to go on that steep roof. The cost of that negates the short amount of time a steeper roof will outlast a 4/12. There are 4/12 3-tab roofs from 60+ years ago still in great shape.

Is it simply supposed to look nicer? That's an internet forum answer I'm thinking I'll hear but I beg to differ it's just opinion.

SPG 12-08-2018 11:27 PM

Just like your tools falling off a steeper roof, so does all the debris like snow, leaves and pine needles. 4:12 tends to hold on to a lot more of that stuff.

Golden view 12-08-2018 11:42 PM

Aesthetics, strength, use of space.

Jay hole 12-09-2018 12:15 AM


Originally Posted by Golden view (Post 7426625)
Aesthetics, strength, use of space.

What makes them stronger?

Golden view 12-09-2018 12:40 AM


Originally Posted by Jay hole (Post 7426643)
What makes them stronger?

Less rafter thrust.

griz 12-09-2018 12:44 AM

can't stand low pitch roof....

6/12 is ok, i'm at home on a 12/12....

ct123123 12-09-2018 01:08 AM

true branches hold on to a 4/12 easier which can then collect other debris and leads to moss etc , but cleaning a 4/12 so easy.

ice and snow stay on a 4/12 longer = more likely for ice to expand into areas it shouldn't, but I'm still not convinced steeper roofs last much longer. Some people clear snow from roofs, and a 4/12 much safer.
Ice dams: a fascia vent could prevent let alone not only 4/12 roofs get ice dams, it's more from attic heat

steeper roofs add about an extra foot or two to an attic which no one really utilizes though. Ok a cathedral church or something will have a smaller footprint but it's still not 'living space'.

Steeper may look more showy but I'm just ranting that's opinion.
Respect to roofers though. there's working at height,, and then there's working at height without a good footing. don't even have to mention tying off really.

true less rafter thrust = less rafter sag, but is a 4/12 going to collapse.

griz 12-09-2018 01:17 AM


Originally Posted by ct123123 (Post 7426683)
....but is a 4/12 going to collapse...

if loaded over the design criteria, yes....

Warren 12-09-2018 07:13 AM


Originally Posted by griz (Post 7426687)
if loaded over the design criteria, yes....

Not true. Most design criteria can be exceeded without collapse. On the other hand, any roof severely overloaded, no matter the pitch, is also prone to collapse.

Big Johnson 12-09-2018 08:01 AM

Because that’s what the architect put on that big paper thingy.

NYgutterguy 12-09-2018 08:13 AM

Me likey 4/12

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Tom M 12-09-2018 08:38 AM

Sevens and eights are a good compromise for storage strength and looks.

They can still be a bit hairy to work on though. when I used to roof full-time I remember rolling up to these jobs new construction sheathing a bit icy and start papering or using ice shield. We would start upside down until we had enough courses on 4 or 5 to turn around and start coming up the roof. Usually a rapper stuffed under the install shingles was enough to hold a bundle in place while you work.

Mordekyle 12-09-2018 10:53 AM

Even modular homes can have vaulted ceilings, but a steeper pitch allows a steeper vault.

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hdavis 12-09-2018 10:56 AM

If you're just talking about shingles lasting on a roof, 12/12 shingles are more susceptible to high winds.

If you have to rake, shovel, or snowblow a low slope roof, the shingles won't last as long.

hdavis 12-09-2018 11:02 AM

A lot of 12/12 have living space in the attic around here. Lower slopes have less or none. The incremental cost of the roofing system to pick up that living space is pretty darn small.

Jonbuild 12-09-2018 11:52 AM

1 Attachment(s)
Reduces the amount of wall siding you needAttachment 470949

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META 12-09-2018 05:37 PM

We just finished framing this 12/12 combo with 5/12 cathedral trusses bonus room over garage. Thing is they gained a whole lot more livable space by doing full exterior wall with roof trusses instead of continuing I-joist over the remaining system.

Side note: We took over this project from a different GC, hence differing housewrap, etc.

Fouthgeneration 12-09-2018 10:35 PM

You want a the top board on the shed trusses to be 2 x 10 or 12" for maximum insulation and venting room under the roof diaphragm, or add a sleepers under the roof deck sheathing, much less heating and cooling year around....

Fire blocking in balloon framing?

Lots of hurricane anchors?

Is a tension cable/strapping needed to hold the rafters together, next to the trusses?

Isn't one of the rafters/trusses traditionally doubled up under the end of the shed roof?

CrescentGutter 12-10-2018 12:47 PM


Originally Posted by NYgutterguy (Post 7426753)
Me likey 4/12

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Especially if hanging 6 inch gutter below a steel roof.

NYgutterguy 12-10-2018 12:53 PM


Originally Posted by CrescentGutter (Post 7427491)
Especially if hanging 6 inch gutter below a steel roof.

Sitting on those snow guards can't be too comfy lol

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