Foundation for a pole barn

[the3stewarts]

I have an existing 20'x25' pole barn that I'm going to tear down and rebuild. The previous owner built it with a hode-podge of techniques. I have a concrete footer poured to grade with 4 course of cinder blocks on one and a half walls, and no footer around the rest of the barn that has the siding nailed to the horizontal studs. I have a few questions..

1.) Would it be better to finish the rest of the footer and have one course of cinder blocks as my foundation? 2.) Would it be best to sink my poles in concrete below the frost line or just sink them in dirt? It seems like if I have 4" of 57's as the base for drainage, I could pour the concrete around the poles?..I'm worried about eventual rot. 3.) Should I pour a 4" footer then build up the foundation to 6" above grade with cinder blocks or just pour the entire footer to grade then add one row of blocks? 4.) Is it ok to pour the entire footer and 4" slab at the same time? 5.) Would you recommend adding the fiber stuff to the cement mix for a stronger slab, use wire mesh to help hold it together, or both?

Thanks, Dennis

[kevin]

I am no concrete expert (struggling with my own design at the moment), but...

It is possible to pour footer and slab in one go, using a "monolitic" slab technique, or "thickened edge" or "floating slab" (all the same thing). The whole structure (slab+footer) floats on the dirt, and moves up and down with frost action as a single unit. In this case, your footer around the edge would only go down about 12 - 16 inches (regardless of frost line). In fact, there would be an issue (I think) with tying it into your deeper existing footer, because that thing would not move with the rest of the floating slab.

Sec> I have an existing 20'x25' pole barn that I'm going to tear down and

[no-email-address-today]

Why would you want to tear it down and rebuild. Just fix it. If the poles are rotten in the ground, pour concrete around them, place heavy metal brackets into the cement (2 sides of post), and bolt the metal to the wood posts. A "POLE barn" has poles in the ground. If you are putting a foundation, then it's no longer a pole barn. Not that it really matters, but that's a fact.

[Don Young]

A pole barn does not depend on any bracing for the walls and roof to withstand the wind load. Without the strength of the poles imbedded deeply in the ground, something else has to prevent the walls from blowing over in a high wind. It is pretty easy to make it strong enough to not settle but not so easy to keep it from blowing over. A few inches of concrete and cinder blocks will have very little sideways twisting strength. Better have someone with experience evaluate your structure on site.

Don Young