Metal building lean to's

[Shovelhead]

Question about different construction methods used for lean to's on a red iron frame metal building.

My current shed has a 12x50 lean to that is under the same roof as the shed.
Seems more so than not I see them built as a separate roof.
The lean to roof drops below the main structure roof up against the side panels.

Seems this type would lead to another place to develop a leak, and certainly a place to gather leaves and other tree shrapnel, because most I see are fairly flat.

Anyone have a good reason construction wise to do it one way or the other?
Roof pitch??

Here's a photo of my current shed, all under the same roof.
30x50

My next shed will be 42x54. Roof pitch yet to be determined.

 

[readhead]

The single plane roof is less expensive to fabricate and install. If the building is very tall there may not be a reason to run the leanto roof all the way up to the eave. Just personal choice.

 

[pmiranda]

My building has a lean-to that shares the roof with the building since they were built at the same time and I wanted as much headroom in the leanto as possible. If I were adding one on, I might do it lower so that I didn't have to worry about trying to match the roof structures, or worry about the foundation of the leanto moving independently from the building and warping the roof or structure of the main building.

 

[loganb]

When I see them with separate roof planes and the lower roof "tucked under" as you described I've always seen as a sign the lean too was added on vs built at the same time. Couple time's I've seen that "add on" look but was done originally there were headroom constraints that prevented from carrying the main pitch down so they flattened out the lean too roof

 

[pmiranda]

Another thing to consider: lean-tos and porches are usually open, so for example on my back porch I set the height so that it was low enough to shade from the evening sun

 

[Shovelhead]

If you look at my photo you’ll see how I had them drop the metal down on the lean to from the 12’ eave.
That helps with shade and blowing in rain.
It’s set 7 1/2’ from the slab.

I’ll do the same on my next one but those porches will have a finished soffit under them.
No more bird **** or drips from sweating metal.
The soffit on one side will be an 8’ ceiling. That will be on the East. A sit and spit area, 12x54.
The west side will be 16x54 with the soffit high as allows. That side will be for tractors, implements and boat parking. Not all at the same time, but capable for any of it.

 

[My Old Tools]

Here's mine, built at the same time. Not sure how else you would do it without adding a bunch of cost making the frame wider.