Lean to Shed

[kjg26]

So in these very basic, and not to scale, drawings you can see the lean to shed from one plane. The length or depth of the shed is dependent on the height because of the roof overhang that i'm working with. The taller the shed is the narrower the roof line is. I don't want to go any less than 24 ft long/deep. Obviouisly I can go shorter and gain more length. But is 9ft tall with a 2/12 pitch and 5'5" at the post end TOO short?

Also the span tables confuse me. I will be using southern pine on this project. And if possible would like to run the rafters unsupported from house to the post. If need be I can put another post, or set of posts, down the center of the shed to support the rafters.

Please advise.

Like I said, the span tables are like greek to me.

 

[sodamo]

Don’t know if this helps or hinders. This spring I extended my tractorshed 22ft. Used 2x6s @ 16 inches OC. Might have gone with 2x8s if longer. My mid support break is 6/16 as I couldn’t put in middle. Need the width to make the turn with mower on. Not much slope due to starting point, but no snow load and not a problem with the rain. (140 in/yr our norm)

 

[kjg26]

Also looks like you did very little cutting of boards. No birds mouth. All brackets?

 

[KennyG]

View attachment 617687View attachment 617688

So in these very basic, and not to scale, drawings you can see the lean to shed from one plane. The length or depth of the shed is dependent on the height because of the roof overhang that i'm working with. The taller the shed is the narrower the roof line is. I don't want to go any less than 24 ft long/deep. Obviouisly I can go shorter and gain more length. But is 9ft tall with a 2/12 pitch and 5'5" at the post end TOO short?

Also the span tables confuse me. I will be using southern pine on this project. And if possible would like to run the rafters unsupported from house to the post. If need be I can put another post, or set of posts, down the center of the shed to support the rafters.

Please advise.

Like I said, the span tables are like greek to me.

It all depends on your use and what you can deal with. I wouldn't go less than 6 feet on any wall because I would end up hitting my head on the rafters eventually. If I wanted to get my tractor in with the ROPS up, I would need 8 feet minimum. Your choice.

Take a look at the span tables again. It's not so complex. You can pick a table with the lowest loading and highest deflection because you don't deal with snow and I'm assuming you will have a light roof like metal. The tables usually have the rafter spacing (12", 16", 24" etc.) on the vertical column and the grade of lumber on the horizontal. The body of the table shows span. Looking at southernpine.com, and the lightest rafter table (20 psi live load, 10 psi dead load, deflection limit l/180) I find that you can span 19 feet with 2x8 on 16 inch centers with No. 1 lumber. Because I know the tables are conservative and we are talking about a shed, I wouldn't worry about 19 feet vs 20 feet and I might go ahead and stretch it to 24 inch centers. The other option, of course, is to go with manufactured half trusses. Then you could go to 4 foot or 8 foot spacing.

It's your decision.

 

[AllByteNoBark]

Keep height in mind if you are pulling the tractor in. I lost a friend several years ago when he was pinned between the building and the ROPS. No one else around so we do not know exactly what happened, just that he is no longer with us. I've been much more attentive to heights of solid objects since then.

 

[dragoneggs]

View attachment 617687View attachment 617688

So in these very basic, and not to scale, drawings you can see the lean to shed from one plane. The length or depth of the shed is dependent on the height because of the roof overhang that i'm working with. The taller the shed is the narrower the roof line is. I don't want to go any less than 24 ft long/deep. Obviouisly I can go shorter and gain more length. But is 9ft tall with a 2/12 pitch and 5'5" at the post end TOO short?

Also the span tables confuse me. I will be using southern pine on this project. And if possible would like to run the rafters unsupported from house to the post. If need be I can put another post, or set of posts, down the center of the shed to support the rafters.

Please advise.

Like I said, the span tables are like greek to me.

No way I would go less than 8ft at your shortest unless something is dictating this. 8ft is a standard board length so no cutting (least waste) and you can 'lean' most anything against it. I'm 6ft +. I sure don't want a roof lower than the top of my head, or ROPS, or other stuff. Go 8ft if you can!!!

 

[sodamo]

Also looks like you did very little cutting of boards. No birds mouth. All brackets?

Right and the tractorshed ends rest on that header and nailed to existing rafters.

 

[sodamo]

As you can tell from my previous pic, my tractorshed grew overtime, not something well planned leading to what it became. The far left started as an open lean to and grew over time with the roof extending down to a 7ft height. Not a big problem, meant for mowers and implements. Eventually it became walled, then garage doors added. Think I ended up with 6’3” doors. Not a problem for my 5ft wife, but she often doesn’t open fully so I have bumped. Do have to be mindful when moving stuff.
2nd the 8ft min if possible.

 

[EddieWalker]

... But is 9ft tall with a 2/12 pitch and 5'5" at the post end TOO short?...

5 1/2 feet is up to you on your height. There is no rule on how tall a wall has to be for a lean to, it's just a question of how often you will hit your head when you are in that area?

The other question is if your measurements are for clearance under your rafters or to the top of your rafters?

Here is an easy to read span table that gives you 20 pounds live load, which is pretty good. You will have to use 2x10's to go 20 feet. The table says that if you use number 2 southern pine, which is very common, you have to space your rafters 16 inches.

Rafter Span Tables

If you use 2x8's every 12 inches, you might have some sag in that roof eventually. 2x6's should not even be considered for this much span. In my mind, the small additional cost of the proper sized lumber will be cheaper in the long run when you never have to deal with any issues in the future.

One of my common jobs here is dealing with what people think are foundation issues. But in almost every house that I've looked at, it's attic issues. Especially open concept homes where they saved a buck going with lumber that was too small. This allows the house to move more and causes cracks in the sheetrock and trim. Sometimes it's been rather severe, and in those cases, the lumber was way off on what they should have used. It costs thousands of dollars to fix some of these homes when it would have cost a hundred bucks more when they built the house to do it with the correct sized lumber for the spans.

 

[kjg26]

So if I use my taller Design i can actually extend it out further to 24'. With exterior wall around 7 ft 4in. Yea that's at the roof. I'm thinking a 2 12ft openings (minus post widths will be better. The rafter runs could be in 2 separate boards. One from the house to the midway post and another from the midway post out to the exterior wall. Would running 2 Boards for one rafter make sense? How would you join the 2 together? Bracket them to the midway post? Also for the header board on the existing house if it were to be 24 ft long along the house would I just double up boards and stagger the seams between boards? 16 and
ft and 8 ft from left ro right for first layer and 8ft and 16 ft from left to right for second layer? What size board for header ledger and run between the midway posts?