Subscribe or Renew Membership Subscribe Renew

pole building lean to

pejka1's picture

Hi all,

I'm attaching  a "lean to" shed to the eave side of my pole building (24'X 56').  The 2x6 trusses extend out and create about a 1 foot soffit.  The trusses sit on top of two 2x10's the are attached to either side of the 6x6 posts  8' o.c.  The trusses are 4' o.c with 2x4's on top  2' o.c.  Metal roof.

I would like the shed to extend out 12' from the wall of the building and keep the same roof line.  It has a metal roof now and I would slide the new sheets under the existing roofing.  If I was to sister a 2x6 to the truss tail there would be about 1" clearance under that to the 2x10 beam. 

What is the best way to attach the new rafters to the existing building and maintain the existing roofline?

How big do these rafters need to be to span the 12' (will have 2x4's over 2'o.c.)  Spacing? 24"?

Let me know what info I forgot.  Thanks in advance.


(post #99436, reply #1 of 8)



(post #99436, reply #2 of 8)

hey, pejka1 knows how to bump!

cu invented the feckless dastard




(post #99436, reply #3 of 8)


(post #99436, reply #4 of 8)

What snow/wind loads do you need to build for?

You are going to be carrying half the new roof load on the posts and beams of the existing structure.  You will probably need to beef up the beams since that side will carry substantially more weight.

The new rafters will need to reach back onto the existing wall for bearing and will need to bear directly onto the beam.


Life and suffering are inseparable.   

"Doubt is not a pleasant condition, but certainty is absurd."

~ Voltaire

(post #99436, reply #7 of 8)

The plan I have so far is to sister new 2x8's next to the 2x6 trusses.  There will be extra room for the 8's since I won't be putting the styrofoam under the steel roof plus the inch that's already there.  I am going to lag screw the existing beams to the posts.  I was also going to cut a wedge/triangle to fit under the 2x8's to help carry the load down to the 2x10 beam instead of just relying on the sister nailing.

I'm in SW Michigan so the snow load is definately an issue.  15 dead/30 live is what I'm planning on.  good enuf?  Thanks for the reply.


(post #99436, reply #8 of 8)

Is this a permitted and inspected addition?  If so, "good enough" is up to your building inspector.

If it were me, I'd add another layer of 2x to the existing beams and through bolt the whole works.

But, I'm using 12" logs to span a 6' - 8" wide woodshed... 

My idea is "how much overkill should we go for?"  and not "should we go for a bit of overkill?"

Sounds like a nice building!

SW Michigan...  I canoed the Pine River about thirty years ago in an aluminum canoe in the rain.  It was a blast and we were very cold and wet by the time we got out.

Life and suffering are inseparable.   

"Doubt is not a pleasant condition, but certainty is absurd."

~ Voltaire

(post #99436, reply #5 of 8)

If you can make the lean-to framing match you post spacing, just hang the new stuff on the existing posts.

You can get mono trusses, use LVLs for rafters, or double up 2X lumber - Depends on your loading requirements.

Honestly - I think sitting a pole barn truss on 2X lumber that's nailed to the posts is completely inadequate. I know people get by with it. But I don't think it's a good idea.

Q: How do you get a lawyer out of a tree?
A: Cut the rope.

(post #99436, reply #6 of 8)

I agree with you about simply nailing 2x onto the posts.  It's much much better to sit it on the posts, let it into the side of the posts, or through bolt.  Sitting on the posts is the best.

Life and suffering are inseparable.   

"Doubt is not a pleasant condition, but certainty is absurd."

~ Voltaire