Shed Roof Question

[Dougryan]

Hi,
Long story, but I want to provide the setup information for my question...
I'm planning a 12 x 16 shed for this summer. That's the max size shed I can build in my town before it becomes an accessory building and has much different requirements, setbacks, etc. So I have to stick to that max size.

84 lumber has a 12x16 Gable roof shed that I really like and plan to build. I have the material quotes and am ready to go. But first, I need a building permit.

The issue with the 84 lumber design is the average height of the roof. The average height = (total height - the eave height) / 2
The town has a maximum average roof height of 8' for sheds.
The 84 lumber kit has a total height of 10' 5.25" and an eave height of 7'3" so... Average Height = (10.438' - 7.25') / 2 = 8' 10 1/8"

So the standard 84 lumber design has an average roof height about 10" to high...

Options:
1 - Change rafter design to target the required average roof height.
2 - Keep rafter design and shorten walls to target the required average roof height.
3 - Combination of shorter walls and rafter design...

I don't really want to lose any of the wall/eave height, but I may have to compromise and maybe take it from 7' 3" to 6' 9" or so... but for now, I considering changing only the design of the rafters.

The standard design has a roof angle of 27 degrees which yields a pitch of 6 / 12. That's great for the northeast when snow load is a consideration.
In order to meet the average roof height of 8', I need to reduce the pitch to about 16.6 degrees and will end up with a pitch of 3.6 / 12.

So, my shed roof question is... I a 3.6 / 12 pitch a reasonable slope for my area, or would I be better off reducing the wall/eave height to achieve a better pitch? If so, what pitch would you recommend?

Thanks,
Doug

 

[Egon]

Does it have to be a peaked roof?

 

[ultrarunner]

If you have to go this route it would seem shortening the walls might increase strength as opposed to flattening the rafters.

Do you think 10" is that critical?

 

[amaxwell]

Can you ask for a variance for these plans?

 

[M5farms]

gable in the states is a roof with 2 sides and a ridge. I don't know whats available in your area but here that's a Utility shed/ portable building and we have a supplier on every corner with them already built and they set it where you want them.

here is and example of one Rent to Own Portable Storage Buildings in Alabama, Georgia & the South

 

[CDN Farm Boy]

Your math is flawed, and once corrected works in your favour.

10'-5" minus 7'-3" = 3'-2" total roof height / 2 = 19". Good to go, nothing to worry about.

It would take a big honkin gambrel roof to have an average height of more than 8'

 

[Dougryan]

Sorry, my equation was incomplete... The 19" would then be added to the eave height rendering the average roof height... 7' 3" + 19" = 8' 10"
Yes, 10" is significant. The woman at town hall said it wouldn't fly.
No, it does not need to be a peaked roof.
I could request a variance. Not sure what the cost or timeline would be for that.
I've looked at the prebuilt / delivered sheds and they come out to be very expensive compared to self built stick framed. Plus, the place where I want to put the shed may not be possible to back in the trailer to drop the shed.
I think I'm stuck with adjusting the wall height and roof angle to meet the requirement.

Thank you for all of the suggestions and for double checking my math
Doug

 

[CDN Farm Boy]

Thinking about this further, their average roof height clause makes no sense.

To reword their clause: Half of the total roof height must not exceed 8'.

Reworded a different way: Total roof height must not exceed twice 8'....which means a 16' high roof is legal.

So in reality, using a gambrel roof you could have a 3 story shed and still be legal (ground to eave, eave to 8' ish and from the 8'ish mark to the peak at 16' above the eave)

As soon as they throw that divide by 2 in there it's pointless. Who's going to build a 3 story 24' high shed? Oh, wait... I would just to prove the point of their clause.

BTW, I'm a licensed carpenter with my own business. Arguing the wording of building codes and bylaws is a bit of a hobby

 

[CDN Farm Boy]

Typing at the same time.....lol

Adding to the eave height changes it.

 

[KennyG]

That is one of stupidest zoning/building code rules I have ever heard of. Leaving that aside, of course, I would build from scratch making it fit the rules. Do you have any concerns about a 7 foot wall height? If you go that way with a 4 in 12 slope on the rafters, you get about into compliance.

If you go to a metal roof, you can use a 3 in 12 slope with no problem. (I would hesitate to go 3 in 12 on a shingle roof in your area.)

 

[Dougryan]

True, you could do an "A" frame shed with the roof going to the ground... Total height 16', Eave height 0'... 16' / 2 = 8'. Eave height of 0' plus 8' meets the requirement.

The more I think about it, and with input from y'all, I'm going to compromise some wall height in order to keep the roof pitch at least 5/12. I really need the slope so that snow doesn't pile up.
Good to go. I'll post some pics as I build this thing.

Thanks again.
Doug

 

[franklin2]

We have the same sort of rules, but not that complicated. My garage ended up being within 15' of the property line, so the building could not be over 15' high. I wanted it to match my house, which had a 8/12 roof. So I had to lower it to a 5/12 roof. Went through all that, and the inspector did not even look at it, or do any measuring. I could have had a pretty nice attic storage space in the top of it with a 8/12 roof.

 

[ultrarunner]

^^^ I've seen this many times...

My former boss was in the wine business and he was doing extensive renovation to one of his buildings and the only way possible was to "Preserve" the rear wall as existing... the tasting room came out spectacular and as the building was nearly completion the Chief Building Official was there and said the back wall looks so out of place and degrades from the project and got the explanation from planning...

Building Official told to to make like the new sections and wrote in right on the permit and signed it...

In other words you never know...

Brother built a super Cabana that was 10 by 20 to match the home... got caught nailing the shingles and had to go through design and plan... the shed looked so good and neighbors approved so he was able to keep it as is... the permit did go from $600 to $1800

When I lived in the mountains of Austria the homes have low slope roofs with massive timbers... they want the snow to stay on the roof for insulation and to prevent dangerous roof avalanches on the eve sides...

Seems we do it different here with the idea of getting the snow moving off the roof with greater pitch...

 

[BigRol]

Anyway you can dig down, put in say a 2' wall of concrete or pressure treated an then back fill to previous grade

 

[ultrarunner]

I looked a shed the yesterday that solved a similar problem...

It is built on/into a little knoll in the backyard and very nicely done...

The dirt on all sides except for where the door is is raised about 18 inches and against a concrete knee wall...

With the flagstone to the double door and grass all around it blends in perfectly and met the height limitation.

 

[TO_Bud]

How many trusses are supplied? Could go with 4/12 trusses (lower sidewalls slightly) and add a couple of trusses to increase load capacity. Could add purlins across trusses to increase load capacity as well.

 

[jclaudii]

I have question, is the prebuilt already to zoning specs or is it taller and breaking them already? I would think that if you are building almost exactly like the prebuilt it would not take much to get a variance since the prebuilt could be delivered and setup, you only building it onsite so as to not mess the yard up Do you guys get different tax/permits for portable shed vs permanent? Meaning if it rests on skids and is classified as moveable you may get a different set of rules for it.

Good Luck!

 

[rd_macgregor]

Is the design you are considering supposed to use pre-engineered trusses or rafters with a peak gusset and/or cross-bracing? If trusses, then you might run into head room issues if you reduce the wall height. I like the idea of raising the outside ground (grade) level so the measurement of average heights is skewed, but I know this would add a lot of cost and complications.
Bob

 

[BuilderML]

I think you may be looking at something wrong. It just doesn't seem right. Double check the code again. The garage we just built this winter the
"MAX HEIGHT" is spec'd to the mid point of the roof which was 15'. I understand why they have a max height requirement. No one needs a second house in the back yard. I also think specing something to a mid point is also dumb but i guess someone needed to come up with something for a code. Good luck with your project.

 

[Dougryan]

It uses rafters that are built on site (by me) using two by fours with gussets at the peak (9 of them). There is also a cross brace, I think the proper name for it is a collar beam, on the odd numbers. I may add the collar beam to the other 4 rafters just to be safe. A couple of extra two by fours is pretty cheap insurance.

Looking good so far. I started on the 12x16 foundation. Using 6x6 posts in a 4' by 4' grid. Lots of holes, but taking it a few at a time.

Doug