Adding walls to an Open sided Pole barn

[2Rocky]

On the ranch is a 50x120 open sided hay barn with I beams as the uprights every 24 feet . It was built in the 60's . Probably 18 feet tall with a slight pitch to the roof.

Given out usually wet and windy winters, Adding walls to this barn would certainly improve the functionality of it. When a local contractor was asked, he wanted to know the Footing Depth. Is there any way to know?

Alternately what is enough and what would ensure adequate footing support for adding walls ? Would a curb along the sides enveloping the uprights add enough support? if so how tall?

 

[Spud McGee]

I reckon the easy way to tell the footing depth is with a shovel or a drill. My initial guess would be no thicker than the rest of the slab. Why would somebody put footings under the slab if they never planned on putting walls up?

I would get a shovel to dig around the edges a couple spots. See if the thing really is more than 4" thick. If it is, you can poke a hole in it with a hammer drill. You'll feel when the drill breaks through. Stop, mark the bit, pull it out, and thats how deep the concrete is right there.

 

[Zeke]

You are asking questions that are impossible to answer w/o knowing your climate. IMO you will need footings from one I beam to the next to build the walls on. If you have freezing then they need to go to the frost line. I'm sure you know that.

The building is already supported on its own so the footings are not going to carry the roof load. Minimum to me would be a 12" T footing with the base being 12 x 6 in undisturbed soil and a 6" stem wall to 6" above grade with rebar and bolts. That is the minimum and that is based on an old code. Certainly not a CA earthquake code.

24' of wall 18' high is likely to not come out straight so you might plan on adding in some 4 x 4's every 8' to hold the wall straight for siding. Really good, tight blocking every 8' will help but since you have 18' H I'd evenly space horizontal blocking at 6'.

 

[jack stand]

I take this as it's still going to be a hay barn and you just want to add a wall to keep wind carried rain or snow out.
I'd take your 24' span and add a wooden post @ 8' intervals dividing your span into 3 by adding 2 posts. Then normally you'd attach horizontal wall girts every 24" or 32" from the bottom to the beam using a pressure treated board at the bottom. Then vertical metal on the outside.
A local contractor who doesn't know the local frost depth should be eliminated from consideration. These additional poles/posts should be in a hole below frost only to avoid movement against the steel structure, not "footers" in the normal sense that support the building. Here your just carrying the wall and providing backup for the new wall. (You can't span 24', so 3 8's) this new post could be 3 PT 2x6's nailed together or a modern manufactured laminated post exactly what would be used in a traditional pole barn.

 

[2Rocky]

OK Climate Zone is 8, 9, 10...Minimum temp of 15 for a few days a year...so frost depth is minimal...
Northern California Coast.
Pad is gravel, no Concrete....
The concern I guess is Wind load.

 

[racecougar]

What are the vertical I-beams attached to? Are they bolted to poured piers, simply sunk into the ground, or...? What size I-beams are they?

Wind load is a very large concern with that large of a "sail". If you're anywhere that requires permitting, you'll almost certainly need engineered plans for that wall size. Even if you're not, it sure wouldn't be a bad idea to get an engineer involved here.

 

[racecougar]

Just to add: Don't underestimate just how powerful the wind loading can be. There are a number of online calculators that you can punch your variables into to get an idea from. For example, on your 120' side, a 60 MPH wind at STP results in just under 10 tons of force. At 100 MPH, that jumps up to nearly 28 tons of force!