Lean-to questions

[Splinter]

I currently have a 30x30 with 10' side walls. On one side, I would like to put up a lean-to/carport area to store stuff and maybe park the trailer or DD.

I would like the area to be 10-12' wide, the length of the building. Pitch would have to be minimal, like maybe even a 2/12 to be able to park under it, etc. snow load shouldn't be a problem, we haven't been getting snow worth mentioning in years, and if we do, I'll broom it off.

What is the best way to secure it to the existing building? Runner strip along the outside of the metal siding with joist hangers? Someone had suggested slicing holes in the siding the size of the boards and attaching them directly to the posts, but I don't know about that.

Any input would be great, I'll have more questions after work!

 

[Brad54]

While we're here, I'll post up a question I'd love to see the answer to on a lean-to type roof: How wide can you make one? Meaning, how long can you make the roof joists without center support poles, and not having expensive trusses?

-Brad

 

[Northstar9126]

I think that you are going to have to cut the metal siding to get flashing behind it or the lean to is going to leak along the garage wall when you get a blowing rain.

 

[Northstar9126]

While we're here, I'll post up a question I'd love to see the answer to on a lean-to type roof: How wide can you make one? Meaning, how long can you make the roof joists without center support poles, and not having expensive trusses?

-Brad

It depends on: how heavy the roof is.
how much load the roof must carry.
the spacing between rafters.
what size the rafters are.
what grade lumber used as rafters.
what species wood used in rafters.
Blah, blah, blah.

 

[hidollartoys]

The residential code spells out rafter span as a function of roof load, rafter size, rafter spacing and rafter material just like northstar says. There are also header tables that define the header where the rafters terminate (away from the original structure). The size of the header is determined by the header span(distance between the posts). You can extorpolate the size of the posts by the weight bearing area required for the header(s). not hard to figure out but no one answer.

As for splinter's question, the best way to attach the ledger board is to remove the siding and attach the ledger directly to the wall framing members. You then attach the rafters to the ledger with joist hangers.

 

[tfi racing]

I'm planning on having a lean-to type roof on the back of my new shop in the future.Since I'm not supposed to have a permanent structure back there,I'm interested in a metal framed tin roofed "temporary" carport more or less.I have seen them around but don't know what they called or where they come from,wondering if anyone has any idea,this might work for you as well.

 

[Splinter]

I think that you are going to have to cut the metal siding to get flashing behind it or the lean to is going to leak along the garage wall when you get a blowing rain.

what if the new roof is able to be tucked up under the overhang of the exisiting? It's a tiny overhang, but one nonetheless.

like so:

 

[thdewey]

You can tie into the roof higher than the side. Just make sure that the gable ends are tied to the structure with lag bolts.

Here are a couple of pix of mine 12'x20':

 

[Splinter]

You can tie into the roof higher than the side.

having a metal roof, I may be asking for a flashing nightmare or is it less complicated than I have pictured?

 

[Junkman]

I am going to assume that this is a pole barn type building? If so, the attachment of the "lean to" is going to depend on the spacing of the poles. More information would be needed before a answer can be given. Most jurisdictions use a 100 year window to determine what requirements the building has to be able to withstand. That means that if there was 2' of snow anytime in the past 100 years, then the roof has to be able to withstand the loading of 2' of snow when you build it. Many times people will build something that will withstand the normal weather conditions, but when that once in a lifetime storm hits, it will collapse. This is why most places are now requiring permits and standards that were unheard of 20 years ago.

 

[Splinter]

yes, pole barn construction, sorry, big detail left out there.

Poles are 7' 6" apart, so that side has 4 poles total. Snowfall, I do not know what the 100 year number is, but I'm positive that we average less than 2' of snow per year, usually small dusters and amounts under 6" at a time. Good thing about STL is that it melts a day later, lol. But yeah, I guess it's not to say that it couldn't happen.

 

[Yamaha74]

I am trying to do the same thing. I have a 30x40x12 high pole barn that I want to add a lean-to to. I want to use it to store my camper under. I just would like some ideas of where to start and how you have done yours. Maybe some pictures.

I will try to post a picture of my barn in a couple of days.