Pole barn lean to

[Slong1958]

Thanks everyone for the info, keep it coming.

 

[KennyG]

I think you would be better served with 2 by 8 for your span instead of 2 by 6. in the long run I would expect you see some sag.

Assuming you have lightweight roofing and minimal snow load, and the actual span between the ledger board and post is about 12 feet, the span tables indicate that a 2 x 6 No. 2 rafter is OK at 16" spacing. However, if you go to 2 x 8 at 24" spacing you will have a bit more margin.

 

[EddieWalker]

Is this what your talking about as far as cutting the tresses and adding the rafters for the lean to. The lean to will be 12ft deep with a 24 in over hang the whole length of barn which will be 52 ft long when finished. The tin on the back will be moved to that wall leaving it open to the barn. Im also wanting to add another 12ft bay then enclose that 22x 36 and make it as dry as possible to house my vintage vehicles. Im going to remove the post that is circled yellow then add a 16 or 18 ft roll up door. This being a load bearing wall how big of a bean would I need?

Yes, the drawing shows what I would do to get more height. As others have posted, it's faster, easier and cheaper to attach a ledger board to the wall and build the leanto under your existing eaves, but you sacrifice height by doing it that way. I would use 2x8s for that span and space them the same as your existing trusses.

For your garage door, millions of garage door headers where built with two 2x12x16's and half inch plywood between them all over the country for decades. I've never seen this fail, but I it's not done anymore that I'm aware of. Now we use engineered beams, or gluelam beams. They are more expensive, but stronger. I don't see why you need to spend the extra money for a gluelam to do this project, but it's up to you and your budget and local weather conditions. Just be sure to frame it correctly with the beam resting on Jack Studs.

 

[drivesitfar]

I'm here to watch and learn and maybe help if I can. I like both the methods of extending the rafters and going under them and guess it would depend on the height you need under your lien too when finished.

good luck!!

 

[MapleLeafFarmer]

I built a 24x40 pole barn awhile back now I want to add a lean to, but the pole barn is only 10ft tall and has a 12 over hang. The lean to I was thinking about you added another ledger board and went from there. I starting looking around on the web and saw this but Im not sure just what has to be done. The 1st is what I came across on the internet the other 2 are what I have. The problem with adding the lean to too my building as in my drawing is the height of the ceiling. The pic with the circle drawn around it looks like the rafter most be either sitting on the top ledger board or attached to it and that would rise everything up and would be ok. I think I know what has to be done but not sure. The 2nd pic is just something I put up to see how tall the roof would be.

If your property line allows.... can you consider expanding out the gable end versus the side?

I was in same position and after some consideration side seemed easy and logical at first but gable end extension was much more useful in the long run for me.

 

[Slong1958]

Eddie you said space my lean to 2x8 the same as my trusses there 48 apart do you think spacing the lean to 2x8x14 will be ok or do I need to go 24?
Guys how much pitch do you think I could get by with on the lean to. I know going with putting another ledger board onto the wall under the roof would only give me around 6 of fall and about 80 of head height on the low low end.
I live near Memphis so we done have much snow.


This video is real helpful
How to frame a lean to roof with rafters and a notched birdsmouth - Pole Barn Shop Build Part 10 - YouTube

 

[EddieWalker]

Assuming that you are going to attach your metal roofing to purlins, I don't see any problem with 2x8's every 48 inches. I would use 2x4's on the flat for purlins and get them 16 feet long. I would also stagger the joints. Do something like cut the first 16 footer in half and put it on, then a full 16 foot long for the next one, then cut another 16 footer in half and so on. Depending on your metal, and from what I see in your picture, I'd probably put my purlins on every 2 feet.

General rule of thumb for metal roofing is that 2:12 is the lowest you should go without having issues. If you seal each panel where they overlap, 1:12 can work, but it's not ideal and more likely to give you issues in the future.

 

[drivesitfar]

Slong: your minimum pitch would have a lot to do with how much snow you get cause rainwater doesn't need much. more snow equals more roof pitch and support. good luck