Pole Barn addition lower than barn?

[jimy]

Pole Barn addition floor lower than barn floor?

I'm hoping to put a lean to addition off the back of my 20x24 pole barn (addition is on 24' end). Hoping to keep the budget down.

The barn is built on ground that slopes down from the back (where the addition will go). To maximize the ceiling height I'm thinking of having the floor for the addition be a step or two lower than the main barn. How practical is this?

- Would this require a short wall to be poured? Below frost line?

- Perhaps if the additions floor was poured against the (bottom) outside of the existing bottom plate it would help? Perhaps add a second bottom plate below the original after excavation?

- I'm open to the addition being pole barn or slab construction.

thanks,

Jim

 

[CraigStu]

I did that in an add-on garage bay. Original and add-on were both conventional stick built construction. Took out two of the studs in the original wall as well as the bottom plate. The builder did a 2 stair drop constructed like you would on a deck. I don't know enough about pole barn construction to help you there but the step down worked great for the 5 years we lived there.

 

[fourbyford]

You don't mention what part of the country you're in... if it gets below freezing, any concrete walls poured should be below the frost line.

The only potential issue might be keeping water out of the lower level because of the different height of the two floors. I assume that was your point on needing to pour a wall? If you pay close attention to waterproofing all joints (floor, walls, and roof) I can't think of any reason it wouldn't work. Depending on how you build the addition, make sure water running off the upper roof doesn't pool around the floor/foundation of the addition... pics or a sketch would help!

...D

 

[pmiranda]

I'm doing the same thing but a metal building on slab. The height of the lean-to floor was set by how far we could go down without compromising the foundation of the main slab.
That happened to be high enough that the lean-to is still several inches above the ground level so it won't flood.
For a pole barn, you've got to make sure there's enough depth on the low side of the main building to hold the poles. I'm guessing that won't be true since the lean-to wasn't originally planned. I do think you can put enough steel and concrete in a retaining step to keep the main building stable, though.