Tag Archives: concrete footing

“One-Pour Post Frame Concrete Footings

“One-pour” Post Frame Concrete Footings and Bottom Collars

As originally engineered Hansen Pole Buildings’ column encasement design, had pressure preservative columns placed to the bottom of an augured hole. Pre-mix concrete was then poured around each column’s lower 16-18 inches to form a bottom collar. Concrete to wood’s bond strength was sufficient to enable this assembly to resist both gravitational forces (settling) as well as uplift.

For further reading on concrete to wood bond strength: https://www.hansenpolebuildings.com/blog/2013/04/pole-barn-post-in-concrete/

There were, however, a few Building Officials who just could not wrap their heads around this as a design solution – they wanted to see concrete underneath columns. Prescriptive Building Codes do mandate for a minimum six inch thick concrete footing below bearing walls and load supporting columns, contributing to this effect.
Reader DENNIS in SALT LAKE CITY triggered this article as he writes:

“I see that you are a proponent of monolithic concrete pours around the vertical posts for your buildings. You have suggested a basket as one way to raise the post 8″ for the footing space. Since I don’t wish to purchase the baskets, how do you recommend suspending the posts at the correct level so all the post tops are level with each other and a monolithic pour can be accomplished?”

Mike the Pole Barn Guru writes:

In response to our friendly Building Officials, Plans’ Examiners and Field Inspectors, we had previously flicked switches on our creative light bulbs to arrive at an engineered solution – we changed our design so column bases “float” eight inches above the bottom of holes, prior to concrete being poured.

Unlike my caricature, levitation is not involved in this process what-so-ever. By nailing a “to be used later in construction” framing member temporarily across each column, at appropriate depth, it makes for a relatively easy design solution.
Once building columns are set in place, it allows for premix concrete to be poured in one simple step both under the column base as well as up sides to create a bottom collar.

This, and all other construction tips and procedures are fully outlined in Hansen Pole Buildings’ roughly 500 hundred page Construction Manual, furnished both electronically and as a hard copy with every new building.

Miracle Truss Concerns

One of the great things about being the Pole Barn Guru is helping people who have construction challenges of all sorts – even those who do not have post frame buildings.

Here is a recent one:

Hi Pole Barn Guru, and thanks for your informative website and blog. I’m using email rather than the website question portal so I can include pictures. I’m a contractor, but my normal specialty is finish carpentry. I wouldn’t normally take on a pole building job, but this one is for my father so I’m helping him build it to try to save some money.

We’ve acquired a 51 x 120 ft building package made by Miracle Truss, a company which is apparently out of business, hence the lack of manufacturer support. The building was purchased years ago by a businessman who never put it up and finally decided to donate it to a church for a write-off. Long story short it eventually made its way to us, still palletized as new, for an incredible savings. So off the bat I’ll apologize for not buying a product from you, as we already have one. But I’m hoping I can use your expertise and perhaps do business in the future.

In case you’re unfamiliar with Miracle Truss, their design uses open-web steel trusses with owner-provided wood purlins and girts. Clips are welded to trusses to receive wood members. The design gives the strength and span benefits of metal with some of the economy of locally sourced lumber. It seems like a good design, but we’re still only in the planning & groundwork stages. The package includes Metal Sales siding and roofing.

My question relates to the use of “splash planks” on a metal-sided building. I know the purpose of the splash or skirt board in typical construction, but I’m doubting its necessity in this particular design. As you can see in the attached pictures, their plans call for a treated 2×6 splash plank which is used as the outside form board when pouring footings, with anchor bolts pre-installed, and then simply left in place and attached to the sill purlin. This places the outside plane of the wall 1-1/2″ outside of the concrete footing. There’s nothing wrong with this design of course, I just wonder if it’s necessary. I’m considering eliminating the permanent mud board, removing the concrete forms and using the sill (bottom) purlin to attach both the flashing and sheet. The last picture is a quick drawing of what I have in mind.

This means I would have to form my foundation 1-1/2″ outside of the stock plans, but save me 340 LF of AWW 2×6. Any thoughts on eliminating the outside splash board?

I’m also trying to decide the dimensions of my footings. Each post will sit over a buried Sonotube pier with a Bigfoot base, which will bear the weight of the building. The footing is really just a concrete”tie beam” and provides a sill for the walls, without really bearing anything. The total thickness of the wall is 17.5″ at the posts (our posts are W12″ I-beam, plus 5.5″ girt.), but only 5.5″ in between posts. I could form a continuous 17.5″ footing over the top of the Sonotubes (my original plan), or form an offset 8″ w footing to match the outside of the wall. I also am not sure how to choose footing thickness, since it’s not bearing. No guidelines are given for foundation in the package instructions, since climate makes a big difference. We are in southern Alaska, our code frost depth is 4 ft, which is where the tubes will sit. But I’m not sure what the footings should be. Any comments?

Thanks again for any advice you can give. I really appreciate the resources you offer. KADIN in KENAI

Dear Kadin:

Thank you for your kind words. We strive to be informative and entertaining.

IMPORTANT DISCLAIMER: The response below is only in regards to the now defunct Miracle Truss which produced the building package you now own. The Miracle Truss brand name is now held by Spider Steel Buildings, LLC. The current Miracle Truss was formed in 2015 and has no connection with the prior company or its products. According to their attorney, Kevin R. Coan of Hinshaw & Culbertson LLP, the current Miracle Truss can and does provide the lumber package as part of its services. Find out more about the new Miracle Truss at https://miracletruss.com/.

My objections to the defunct Miracle Truss system has always been how does one go about finishing the inside of the building with the steel frames in the way and (very important to most) the having to source one’s own lumber which can end up in a sticker shock situation.

Your Miracle Truss building’s outside 2×6 splash plank is there for a reason, and should be used. The bottom of it is the point at which level grade is on the exterior of your building. If it is not present the steel base trim will probably end up in contact with the ground outside of your building – which will result in premature deterioration as it slowly rusts away.

As to your footings, the best advice I can give would be to contract with a registered professional engineer in your area who can do an analysis of the forces upon your building, wind load, snow load, seismic, exposure, et. al. Also the engineer will need to take into account the bearing capacity of the soils at your site.

Good luck and let me know how it all turns out!
Mike the Pole Barn Guru

Afraid of Buying a Pole Barn Home

Reader Carol recently wrote me this: I’m encountering problems with folks looking at my house and being “Afraid” of buying the house.  Because it’s a pole barn house rather than a stick house.

 What can I tell these folks to help them understand pole barn houses are still a good purchase?”

Gambrel roof pole barnI happen to live in a “pole barn” (aka post frame) home and can tell you it is a fantastic building. Here is my response to Carol:

“Some of your challenge may be in how your home is being presented. If you are telling people it is a pole barn house, you are probably turning them off just because of the term “pole barn”. Whether post frame or stick built, what you have is a “wood framed” home. Period, end of story. Same with when you have an appraisal done. If your post frame home is not attached to a continuous perimeter concrete footing, then the foundation should be listed as being, “Pressure preservative treated wood foundation”. It all just comes down to a matter of concept.

Post frame construction happens to be fully recognized by the IBC (International Building Code) as being a conforming structure. Having the engineer wet sealed plans for your building also allows you to market your home as a building which is actually designed by a Registered Design Professional – not just somebody winging it together. In most areas, very few if any, homes are actually engineer designed. In the event you do not have the original engineered plans, it may behoove you to invest in an engineer who can provide “as built” plans for you.

As in selling anything, make a list of the features your home has which are exceptional, along with the benefit to the end user of each feature. A feature without a corresponding benefit is not going to make the cut. All the prospective buyer cares about is what is in it for them. Once those benefits are perceived as being greater than the prospective investment, all of those fears go away.”

What Color Steel Roofing is Coolest?

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’m building a house with steel roofing with Galvalume. Is the painted cooler than the shiny aluminum with no paint? What color should I use? Thank you MIKE

DEAR MIKE: If the idea is to create a “cool roof” then you want a product with high solar reflectance as well as high thermal emittance. The difference in energy performance is due to more than just the color of the steel roofing. The paint which the coil coating companies apply to the steel has added chemicals which are designed to reflect infrared wavelengths. As such, painted steel roofing is the answer to your question, and the best performer will be white.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I am building a 40’x64′ pole building currently and have encountered an issue with my holes.  I have augered 24″ diameter holes 5 feet deep and poured between 12″ and 16″ of concrete in the bottom of each depending on overall hole depth.  During augering I encountered rocks that sent the bit off course.  The result is 2 of my 28 posts just barely fit into the holes and consequently only sit on the edge of the concrete slab in the bottom (no precast cookies here).

Have I negated the advantages of augering larger holes and pouring concrete by only sitting on the edge with the column?  If so, what’s the best way to remedy this?  Or, do you think I am ok to proceed and the concrete will still do its job?

Thanks, truly enjoy your information. AARON IN GILLETTE

DEAR AARON: The generally accepted school of practice says there should be at least four inches of the concrete footing extending past any point of the columns. By having the load so far off center, it could cause the footing to ‘tip’ downward beneath the column and result in settling. If the two holes in question are off in the same direction, you might consider shifting the building slightly to compensate. Otherwise, you could enlarge the two holes to allow for an extension of diameter in the direction which is a problem.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: Is there an issue with a flat 2×6 sagging if has a really large window unit on it? Thanks, BEN IN HUGUENOT

DEAR BEN: Thank you very much for your question. Prior to the siding being installed, there is a possibility the girt below it could sag. This can be remedied by placing one or more vertical blocks temporarily between the pressure preservative treated splash board and the girt below the window. This will hold the girt level, until siding can be installed. Once the siding is in place and properly fastened, the girts will be fully restrained from movement.

Mike the Pole Barn Guru