Pole barn lean to

[Yambers]

I need advice on building a lean to on my barn.

Details and general info.
- In Indiana, so will have some snow.
- Lean to will be about 20' x 48'. Probably closer to 19' as I will be using 20' boards for rafters.
- Will have a 1-2 foot drop from barn to outside edge.

My question is mostly concerning the 20' rafters. Trying to build it safe, but not to the point where it is built out of tree trunks or 8x8 lumber. Also cost is always a factor.

Question is, will a 2x8x20 support the 20' span? Doing about 4' on center with sheet metal roof.

Suggestions from the pros please.. Appreciated!!

 

[AZMark]

Do you not have or not worried about building codes?

You could get probably something like that drawn up pretty cheap and be certain about safety, code and not wasting money over-building.

I did a detached rv garage so they had to do foundation, electricity, etc. and it was around $1k and they handled all the permits. Pole barn would be a lot less work to design.

 

[Yambers]

Do you not have or not worried about building codes?

You could get probably something like that drawn up pretty cheap and be certain about safety, code and not wasting money over-building.

I did a detached rv garage so they had to do foundation, electricity, etc. and it was around $1k and they handled all the permits. Pole barn would be a lot less work to design.

$1000 to have it drawn up and permits? Kricky. That woyld negate me building it myself for the savings.

I'm aware there are codes, and permits are the way to go. My question is more general as I am building it myself, which I am more than capable and trained to do, and I know it doesnt have to be as robust as a floor joist in a house with spacing and such. Its just for covering trailers and tractors after all. Im just thinking about the 20' span and if I need to pay $75 a board for 2x12's or if I can save a few bucks with 2x8's or 2x10's as rafters.

 

[Babin Farms]

At 20' and 4' in between I would be using 2x12's. That's too long of a stretch for anything smaller unless you are going to use a laminated 2x8.

 

[zipper]

I threw up this wood shed 15 years ago. I never got around to finishing the facias, soffits and returns but it has held up to VT snow loads, knock on wood. I used 2x8x18 for rafters and predominately spaced at 4’, however I did add a couple in the middle to add support for snow. My bay is 14’ wide and the rafter tails overhang the box beam by 4’. The beam that supports the rafters was cut full dimension on my Woodmizer at 2x14”. That 14’ span has a drop of 4’, just under a 4/12 pitch. That is pushing it in this area as snow takes a long time to slide off.







Snow can take days to slide off this shallow pitch as seen by the progression below.



It’s just a wood shed and a place to park the mower and Polaris in Summer.
And a temporary place to put the new Weber box.

 

[gt5pilot]

What is the snow loading by the UBC for your area?

A 2x12 on 24" center will barely make that span (23'-9") with a 20lb snow load calculation. For reference, in CO snow load is 90-120lb based on location. If you can find out what your code is the calculation is pretty straight forward.

Also depends on the specific species of wood you intend to use; Douglas Fir, Larch, Southern Yellow Pine? SYP is the best of the three listed.

And I would add blocking between the rafters to prevent twist @ midspan.

 

[AZMark]

$1000 to have it drawn up and permits? Kricky. That woyld negate me building it myself for the savings.

Yea I think it would cost much less but I get it. Mine was fairly complicated and that was about 1.5% of the project cost, so I thought it was a pretty good deal. It allowed me to build it/hire it out myself from there.

Hiring a general contractor and just telling them what I wanted would have cost me $10-15k more.

Good luck with it!

 

[Yambers]

At 20' and 4' in between I would be using 2x12's. That's too long of a stretch for anything smaller unless you are going to use a laminated 2x8.

I drew the plans up based on using 2x12's, but they are $76 a PER BOARD!!!. hence me asking advice. ha

 

[Yambers]

I threw up this wood shed 15 years ago. I never got around to finishing the facias, soffits and returns but it has held up to VT snow loads, knock on wood. I used 2x8x18 for rafters and predominately spaced at 4’, however I did add a couple in the middle to add support for snow. My bay is 14’ wide and the rafter tails overhang the box beam by 4’. The beam that supports the rafters was cut full dimension on my Woodmizer at 2x14”. That 14’ span has a drop of 4’, just under a 4/12 pitch. That is pushing it in this area as snow takes a long time to slide off.

View attachment 180515

View attachment 180518

View attachment 180514

Snow can take days to slide off this shallow pitch as seen by the progression below.

View attachment 180517

It’s just a wood shed and a place to park the mower and Polaris in Summer.
And a temporary place to put the new Weber box.

That snow creeping down is hilarious. I appreciate the pics as well. I think I am getting greedy with trying to span 18-20' without any other bracing. I was hoping to park trailers side by side in it, along with the tractor and some other "stuff". I might have better, and safer, luck doing it in 2 sections, each 10' wide. But then the price I am saving from the 20' boards is just transferred more of the 10' boards. It sucks being cheap. haha

 

[Yambers]

What is the snow loading by the UBC for your area?

A 2x12 on 24" center will barely make that span (23'-9") with a 20lb snow load calculation. For reference, in CO snow load is 90-120lb based on location. If you can find out what your code is the calculation is pretty straight forward.

Also depends on the specific species of wood you intend to use; Douglas Fir, Larch, Southern Yellow Pine? SYP is the best of the three listed.

And I would add blocking between the rafters to prevent twist @ midspan.

All great points. Indiana snow is hit and miss. I would have to research the actual load.. And I would be using yellow pine. That's what I priced. And yes to the blocking.

 

[Babin Farms]

Totally understand the $$ situation but trying to span 18-20' is going to take something larger than a 2x8.

Have you checked your area to see if there are any lumber/construction auctions coming up?

I've gone to many of these PEAK auctions and bought stuff cheap. Just need to watch what your buying, there's a reason it's there.

Peak Auction Schedule – Home Improvement Material Bought Cheap

www.peakauction.com

 

[gt5pilot]

Are you in the middle of the state?

 

[Yambers]

Totally understand the $$ situation but trying to span 18-20' is going to take something larger than a 2x8.

Have you checked your area to see if there are any lumber/construction auctions coming up?

I've gone to many of these PEAK auctions and bought stuff cheap. Just need to watch what your buying, there's a reason it's there.

Peak Auction Schedule – Home Improvement Material Bought Cheap

www.peakauction.com

I drew up plans using 2x12's. Hard justifying the cost for the project at all just to keep trailers out of the weather. Ha

I will look into the auctions. Didny know those existed.

 

[Yambers]

View attachment 180563
Are you in the middle of the state?

Right in center. Is the 20 for inches?

 

[zipper]

That snow creeping down is hilarious. I appreciate the pics as well. I think I am getting greedy with trying to span 18-20' without any other bracing. I was hoping to park trailers side by side in it, along with the tractor and some other "stuff". I might have better, and safer, luck doing it in 2 sections, each 10' wide. But then the price I am saving from the 20' boards is just transferred more of the 10' boards. It sucks being cheap. haha

2X8's spanning 18-20' will sag over time on such a shallow pitch. You could truss the construction or divide the 20' span into 2 bays with 4x4 posts in the middle supporting a small beam running under the ceiling joists or collar ties. Then add a "dead man" post between the joist and rafter. You can use that upper area for storage too.

 

[gt5pilot]

Right in center. Is the 20 for inches?

Yessir - that puts you at a 2x12 on 24" centers to span 20'by UBC Snow Load calculations. You have some wiggle room and could go out to almost 24' if you wanted to. These calculations assume a 1-7/8" purchase on each end of the rafter (sitting on top of a 2 by "whatever you header height is" being sufficient).

 

[Yambers]

Yessir - that puts you at a 2x12 on 24" centers to span 20'by UBC Snow Load calculations. You have some wiggle room and could go out to almost 24' if you wanted to. These calculations assume a 1-7/8" purchase on each end of the rafter (sitting on top of a 2 by "whatever you header height is" being sufficient).

Greatly appreciate the information. I might follow @zipper advice and make it a 2 bay instead of 1 big bay. I could get a full 20' that way as well, with 2 bays at 10'each.

 

[zipper]

Another advantage of 2 bays with a beam on top of the posts in the middle is you can buy shorter rafters and overlap them at the beam. I can take a picture of our horse barn to show you what that looks like later. You won’t need to buy 20-22’ 2x8’s at a premium price. You can buy 12’ers instead.

 

[zipper]

This is the horse barn I built 15 years ago with the help of my Woodmizer bandsaw. I did buy rafters and 2x4's but most everything else I cut.
The boards for the board and batten siding are 1x18" pine. Other woods used were red oak and black cherry for posts and other structural needs like door posts and headers.



Both roof spans are too long to reach with one length of rafter. The span on the left has 3 pieces of 2x8 to make one rafter.







I need to clear the mill off and start sawing again.

 

[Yambers]

Helpful. I appreciate it.