Adding lean to on pole barn

[radman1]

We have a 60x100x16 metal pole barn shed and considering adding a lean to on one side. Current shed has 10' apart posts. We have sprayers and grain carts in the shed that take up lots of space and only see seasonal useage. Want to use it for machinery shed with some equipment up to 12' tall and up to 16-20' wide. Would like it to be about 25' deep. What do we use for rafters and joists if front posts are 20' apart? How do we attach it to the existing pole barn?

 

[ampsucker]

i think you'll have to go to wooden trusses or steel frame for those types of widths.

i added a leanto structure to a metal building and was able to use 24' 2x12s for rafters and doubled up 2x10s for the joists, but my 5x5 support poles were maxed at only 14 feet apart. i ended up with a 24' x 48' leanto of good strength.

i don't think i would try 20' spacing without gussets or trusses if staying with wood.

for the distances you are talking about, dimensional lumber in joist or rafter configuration is going to be too weak and probably more expensive. i would look into having someone build you some trusses or go to a steel solution. a steel truss will be lighter and stronger and can give you the spacing you want.

i would think you could take your wish list of dimensions to the local truss companies and see what it will cost. then you can decide if you want to tackle doing the work yourself or farming it out....

amp

 

[radman1]

Hadn't thought about a truss company. Thanks for the idea.

 

[QRTRHRS]

I would think that your roof pitch might be too shallow for a wooden truss. Since you need over twelve feet at the eave for a margin of safety for those high implements and the existing barn wall height of sixteen feet, that twenty five foot lean too depth will be maybe 1/12. Doesn't hurt to ask though.