Of Sheds and Gambrel Roofs

[Jason Roehl]

Ok, so I am about to spend my copious free time building a much-needed shed in the back 1/40th.

The basic layout will be that the base of the shed will measure 10'x12', with 7' side walls and a gambrel roof. The gambrel shapes will be on the 10' wide ends.

Here's my dilemma. After a little poking around on the internet to refresh my geometry, I came up with two options for the gambrel, but I'm not sure how they will look.

Option 1: Build the gambrel as 4 sides of a regular octagon. If each leg is 4' (conveniently the width of a sheet of ply), that will give me an additional center height of just over 5', and overhangs on each side of about 2.75" (which I would cover with hardware cloth for venting).

Option 2: Build the gambrel as 4 sides of a regular decagon. To get the few inches of overhang on each side, the 4 sides would have to be about 3.25' each, and I would only get about 3.6' of additional height in the center.

Now, before you think that option 1 is the no-brainer, I am trying to skimp on materials a bit. I could use the roof ply cutoffs to make the braces for the gambrel frames, and I would need about a bundle fewer shingles. My concern is that option 2 won't look quite right proportion-wise. I do want to be able to have some shelving to somewhat use the "loft" area, so option 1 may be the way to go.

Thoughts? (And, if anyone is incredibly bored and good with a CAD-type program... ;) )

[Thom Porterfield]

The problem I see with your option #1 is that there is no material left over for eaves. You live in Indiana--I'm pretty sure it rains/snows there--what's your solution for run-off?

I am not incredibly bored--just a little bit (that's why I hang out here a lot)--and I am skilled with AutoCAD, Sketchup, etc. I'd be happy to discuss your project.

[Mike Davis NC]

The one thing I have learned about building sheds is the wider the over hang the longer the building stands. It really helps to keep water off the side of the building and away from the foundation.

[Steve Peterson]

The plans I have seen do not follow true octagon/decagon angles. Maybe this helps give a better slope for runoff on the 2 middle section. Or maybe it just gives a more pleasing look.

I would design it so the center section has the minimum slope for runoff of the shingles you plan on using. This is probably a 4" pitch per foot at an 18.4 degree angle. The outer roof sections are at a 54.2 degree angle giving the same angle for both joints.

If you want more loft area, then why not use 8' walls? My personal preference for a 10x12 shed would be to use simple triangle shaped trusses (or a central ridge beam) with inside walls that are tall enough to stand up an 8' 2x4 without hitting the roof.

Steve

[Steve Peterson]

The one thing I have learned about building sheds is the wider the over hang the longer the building stands. It really helps to keep water off the side of the building and away from the foundation.

Gambrel roofs do not provide a lot of overhang unless it has small wings where the roof meets the walls. Then there are 6 roof sections, 4 at 4' each and 2 at maybe 18" each.

Steve

[Chris Padilla]

Learn Sketch-Up, Jason...it'll be worth your time. :)

[Jason Roehl]

Thom and Mike, I'm a painter, so I'll make sure it's good to go. The floor will be treated plywood, on 2x6 joists, which will sit on 4x4 runners, set on 9 pavers/paver stacks. The only good place for me to put the shed puts it in an easement, so I want to make it relatively easy to move (i.e., a chain and a backhoe or come-along). I'll be using something like T1-11 siding, made of OSB, and with 7' side walls, it will cover the floor joists.

Steve, I'll be storing mostly lawn/garden equipment in it: rototiller, chipper-shredder, lawnmower, rakes, shovels, weedeater, etc. Just doing some quick sketches on graph paper made me realize 8' side walls were too tall for the proportions to look right. The first shed I ever built was 8'x8'x8' with a low-pitch roof on it, and it looked too tall and skinny. It didn't have an overhang to speak of, I didn't paint the pre-primed siding, and that was still in good shape when we moved 5-6 years later.

Chris, my brain is full. I'd have to forget my kids' names or something to make room. ;) Seriously, though, I just don't have time right now--I plan to pick up materials tomorrow and get at it.

[Adam Strong]

Here's a shot of my shed. It is your option #1 with it extended down past the top of the wall. I don't recall how far down, but I ended up with 8-10 inches of overhang. I designed the structure myself and liked the look of the "half octagon" style better.