Tag Archives: concrete cookie

Hi, I Should be an Engineer

Hi, I Should Be an Engineer. Can You Tell Me What I Left Out?

Seemingly every Spring I receive an email similar to this one from JOHN in UNION DALE, who it sadly appears has not done much (if any) homework in reading my articles.

JOHN writes:

“ Hi, I have been doing a couple of months homework on making my pole barn, my plan is a 30×50. Right now my plan is using (16) 6x6x16 pole about 52 inches in the ground, the spacing between posts will be 10 ft, now I have not decided on a concrete cookie before the setting the post or gravel first has a drainage layer the set the pole and then use about 5 bags of concrete for uplift protection and the normal back fill, for the posts I got post protectors, so the wood is separated from the soil, my plan is to use double  2×12 for the top strapping with the posts notched at the top for added snow load, has far has the roof it will either be a 4/12 or 5/12 pitch my plan is using 2×6 rafters that I’m making on the ground and hoisting up by myself and they will be on 48 inch on center, my purlins are going to be 2x4s about 2ft apart and standard metal to finish it off, if you can can you please let me know if I left anything out, thanks ps I forgot to say the door opening on a non-load bearing wall will be a 12ft wide and 10ft tall, I’m thinking about putting a door  on a load bearing wall a 10ft, all doors are going to be sliding barn doors.”

Mike the Pole Barn Guru Responds:

Well John, you have left out a crucial part. One no proper pole barn should be without. Plans designed and sealed by a Registered Professional Engineer specific to your building at your site. To build without them is, in my humble opinion, fool hardy and I cannot endorse your plan of attack or methods of construction without them. Outside of this – attempting to field construct your own roof trusses is not a good choice. Prefabricated trusses are truly a bargain, especially when considering risks involved should your home made trusses collapse injuring or worse killing you or a loved one. 

For last year’s related article, please read: https://www.hansenpolebuildings.com/2019/05/self-designed-pole-buildings/

For extended reading on the misadventures of site built roof trusses: https://www.hansenpolebuildings.com/2018/12/site-built-roof-trusses/

Sutherlands® – Calling them Out

I have a serious case of “like” for The Home Depot®. When my children were little, every time we got near one, they would start to chant (in unison), “Home Depot…..Home Depot”.

Yesterday morning I was in The Home Depot® at Grand Junction, Colorado. It was a special moment, when a gentleman came up to me (having perhaps recognized the red Hansen Pole Buildings shirt I was wearing) and told me he had purchased one of our buildings, and was constructing it now!

It isn’t very often I get to meet one of our clients, and even rarer when they are still building – so this was great fun for me.

He related to me how he was originally intending to order his new pole building kit package from Sutherlands® Lumber in Grand Junction. They had even provided him with plans, which he had submitted to the local Building Permit issuing authorities to acquire his Building Permit.

The Sutherlands® plans (which were approved by the Building Official) had a foundation composed of throwing a 90 pound bag of Quikrete® in the bottom of the hole. The pressure preservative treated column would then be placed, and another bag of Quikrete® dumped in around the post.

Pole Barn FootingIt turns out the customer decided the Sutherlands® building was going to be inadequate. His only complaint at all with a Hansen Pole Building was the size of the holes and amount of concrete it took. Even then he admitted Hansen was a better buy, even with the extra concrete costs.

The loyal readers of this column certainly will recall my railing against concrete cookies, in earlier posts: https://www.hansenpolebuildings.com/blog/2012/08/hurl-yourconcrete-cookies/ and https://www.hansenpolebuildings.com/blog/2014/03/concrete-cookies/

In my humble opinion, what is being purported to be adequate by Sutherlands® (whether the Building Official approved it or not) is close to criminal.

Our client’s building has 40’ span prefabricated wood roof trusses, with a double truss every 10 feet. In his 30 psf (pounds per square foot) roof load, it results in each truss bearing column having to support 6860 pounds of load. Added to the fun is a soil bearing capacity of only 1500 psf.

The International Building Codes (IBC) require footings to be a minimum of a nominal six inch thickness. So let’s explore the design solution promulgated by Sutherlands®.

At 90 pounds per bag of Quikrete® it would take about 1.65 bags to make a cubic foot. If this was all poured to a nominal six inch thickness as a footing pad beneath a column, it would roughly form a two foot diameter footing. Now granted, this is not how Sutherlands® would like to see it done, however we are going to give them the benefit of the doubt.

A two foot diameter footing has an area of 3.14 sft (square feet). Multiplying by the 1500 psf allowable foundation pressure, a pad such as this would support 4710 pounds….when it needs to support 6860 pounds – it is overstressed by nearly 50%!!!

Talking with a building kit supplier (such as a Sutherlands®) who is recommending bags of Quikrete® to backfill the bottom of a column hole? Might want to really think about the design being bought into.

Bagging it? Prepare for the possibility of a roof line with some humps and bumps in it, at a future date.

When people such as Sutherlands® provide under designed buildings, it gives our entire industry a bad name. I’m calling Sutherlands® out here – and challenging them to actually provide Code conforming pole building kit packages