Tag Archives: building on bedrock

Some Pole Barns Deserve a Proper Burial

Some Pole Barns Deserve a Proper Burial

Reader STEPHAN in OGDENSBURG writes:

“Dear Pole Barn Guru,

I have a 30ish year old 32 by 54 feet horse pole barn where half the poles heaved some for more than 1 foot over the years. I need to fix it this year because I am afraid that the strain will make the structure collapse. The code in my area says that post must be buried 5 feet because of frost.

The issue is that the bedrock is between 3.5 and 5 feet below grade. I have an 8 foot wide concrete pad/runway in the middle of the barn (the whole length of the barn). I would like to do it right to last many years.

I considered these different options:

– replacing each posts with sonotubes with bigfoot at the bottom sitting on the bedrock (a lot of work if done with bags of concrete because I would have to do them a few at a time to keep the integrity of the structure)

– replacing bottom of each post with footing sitting on the bedrock and permacolumns (a little less work because the volume of concrete is just a little less)

– pouring a “bond beam” or a full slab on the inside against the posts with thicker sides to support the structure (as per engineer) and then building walls on the inside with 2×6’s to support the roof, and then removing the posts ( I will be losing about 6″ all around because the new walls will be inside the existing shell). I like this idea because I could prepare the area over the winter and get it poured in the spring. My issue is what would I do with the existing slab in the middle of the barn? Should I attach it with rebar and epoxy, pour over or remove the existing slab?
If I go with the last option, what would I use to support the lean-to? If the slab does not have a full foundation that would mean that it is “floating”, should the posts supporting the extension also be “floating” to ensure that they move together?

Or do you have a better option to suggest?

I have attached pictures to show how bad it is. You can see how crooked the ends are by the siding angle and the window in the lean-to area. Thank you for your help.”

Mike the Pole Barn Guru responds:

I am not one to pull any punches – I’ll give my honest opinion, even when I don’t feel it is one you want to hear.

There comes a time when reality sets in….in your pole barn’s case reality will be it needs to be knocked flat, bulldozed into a big hole, lit afire and then replaced. Otherwise, you are going to spend a phenomenal amount of time and money for any fix, and all are just band aids for something truly not worth saving.

Your frost heave issues are due to poor site preparation. Please read this information about properly preparing a site: https://www.hansenpolebuildings.com/2011/11/site-preparation/

and preventing frost heaving: https://www.hansenpolebuildings.com/2011/10/pole-building-structure-what-causes-frost-heaves/.

If you absolutely insist upon saving your pole barn, you should hire a geotechnical engineer to evaluate your site and give you expert advice. If you decide to give your barn a proper burial, start over with engineer sealed plans and a kit that gives you a lifetime of safe use…for you and your horses.





Dear Guru: Should I Use Concrete Sonotube Foundation?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: I am planning to build a post-frame house 32×40. I built a 16×16 post-frame barn last Summer as practice and found that I hit bedrock at 2 to 2.5 feet. I know that most post-frame buildings require a 4 foot hole with a concrete footing to keep the post from settling, while also providing lateral strength. I don’t seem to need the depth for settling issues since I’m building on bedrock, however, I lose the lateral strength of a deeper hole. Is there a way to add lateral strength? Also, since I’m not getting that support from a deep enough hole, would it be better to use a concrete sonotube foundation with sturdi-wall brackets to mount my posts?


DEAR DIGGING: If you think about it, a sonotube filled with concrete and a bracket on top, is going to provide less lateral resistance than a column in a hole filled with concrete. Depending upon building dimensions, exposure to wind and soil conditions above the bedrock, it is very possible increasing hole diameter and using a complete concrete encasement could do the trick.

As you firm up your plans, we can provide a preliminary hole layout. From this, you can dig the holes and give an exact measure to what point solid bedrock is encountered. This will allow for a design to be created which will minimize the amount of digging and concrete, without negative effect upon your structure.

DEAR POLE BARN GURU: 30×48 pole bldg. was just completed. The 4×6 posts were set on cement cookies 16″ x 4″ every 8′ and then packed with dirt. Is it too late to remedy this situation? Should I dig down to each cookie and pour some cement to encase each post?  The bldg. was just completed last week, so dirt is still freshly packed. What do you suggest? EVENTFUL IN EVANS CITY

DEAR EVENTFUL: It is not too late, but it will involve work which could have easily been avoided. The concrete cookies are not going to be adequate to prevent settling and they do nothing to prevent uplift.

I’d start digging. Make sure the bottom of the hole (directly above the cookie) ends up larger in diameter than the area closer to the surface. You should probably go to two foot diameter and then pour at least 18 inches deep of premix into the hole.