Tag Archives: building site preparation

Concrete Slabs on Grade for Cold Climates

Concrete Slabs on Grade for Cold Climates

My lovely bride and I have a shouse (shop/house) in Northeast South Dakota, where it can tend to get chilly in Winter. Reader TERRI in DULUTH is in a similar situation and writes:

“What type of slab for cold climates do you recommend?”

Well Terri, thank you for your patience in awaiting a response, your email address was not included with your question, so I was unable to message you back as quickly as I would have liked.

PLEASE – If writing an “Ask the Pole Barn Guru” question include your email address.

Injecting some humor (sadly, I have to point it out as not everyone gets it) – I would recommend a concrete slab.

Before diving into this subject – accept one fact, concrete slabs will crack. If you are expecting otherwise, you are setting yourself up for disappointment.

First key to a successful slab is excellent site preparation: https://www.hansenpolebuildings.com/2017/02/building-site-preparation/

Second – insulate your slab’s perimeter. 2021’s International Energy Conservation Code (IECC) provides guidance to meet energy code requirements for every county within our country. Begin by looking up your Climate Zone: https://codes.iccsafe.org/content/IECC2021P1/chapter-3-re-general-requirements

I will cheat and tell you Duluth (St. Louis County) is climate Zone 7.

Scroll down to Table R402.1.3 to find Insulation Minimum R-Values.

In Climate Zone 7 your slab perimeter must be insulated to R-10 and be four feet in depth. 

Weirdly enough, Minnesota’s Building Code only requires footings to be at 60 inches of depth in your area (https://www.revisor.mn.gov/rules/pdf/1303.1600/2015-01-23%2012:37:31+00:00). 

Although actual frost depth in your area is more like 80” in depth:

I would probably look at augering holes no less than 72 inches in depth, using a bottom collar of 18 to 24 inches (per your engineered building plans). This would allow you to trench between building columns and install R-10 rigid insulation along your building’s perimeter to a depth of four feet.

If you are going to do radiant in-floor heating you should be placing R-10 beneath your slab and on top of a vapor barrier of no less than 6 mil visqueen (I prefer 15 mil thickness to reduce chances of perforations during pouring).

Column Types, SW Missouri, and Site Preparation

Today’s Pole Barn Guru discusses reader questions about types of columns used in Hansen Pole Buildings, what type of car for a small 2 story barn, and the best site preparation.

DEAR POLE BARN GURU: Good morning. I was just running through your website looking at the different materials you guys use for your buildings and I could not find the type of column you use. I know some people have 6x6s, some use 3ply 2x6s and others use the glulam columns, both spliced and un-spliced. If you could let me know now your method that would be great. Thanks! BLAINE

Concrete slab in a pole barn

DEAR BLAINE: We supply either solid sawn timber columns or glulaminated columns depending upon where building is located, client request, and/or climactic conditions. Glulaminated columns have finger jointed and glued splices – unlike some nailed up columns.


DEAR POLE BARN GURU: I’m looking at wanting to build a 30 x 40 2 story pole barn with the barn roughed in for a second floor and just one small garage door what kind of car should I be looking at? Do you do work in Southwest Missouri?

DEAR SOUTHWEST MISSOURI: Well, you are probably best to get a car fitting your family’s needs. Personally, I drive a 2012 Chevrolet Avalanche – because if something hits me I would like to survive.

For a single vehicle overhead garage door 10 feet of width and seven feet of height should keep your mirrors on. For sake of resale value, you might want to consider going with a 16 foot wide door, as it offers wider appeal to future owners of this building.

Hansen Pole Buildings provides custom designed engineered post frame buildings kits everywhere in the United States – even Southwest Missouri.


DEAR POLE BARN GURU: What preparations must be made for the ground for the area that a pole barn is to be built on? Is a base such as a concrete slab, or gravel required, or may one be built only with the poles in the ground, and the concrete holding them in place? JOSHUA in BECKETT

treated postDEAR JOSHUA: Simplicity is a part of post frame (pole barn) construction. If your building will not need a concrete slab on grade, then you could merely auger holes, then place them with limited amounts of concrete in hole bottoms to resist settling, overturning and uplift. If your future plans include a concrete slab, then more extensive site preparation should be done to insure proper results: https://www.hansenpolebuildings.com/2011/11/site-preparation/.


Barn Conversions, Raising a Building, and Pole Barns on Concrete Slabs

Today’s Pole Barn Guru discusses a possible conversion of an old pole barn, raising a building, and how site preparation helps with concrete slabs.

DEAR POLE BARN GURU: Have a 40’ x 100’, 2 sides enclosed, pole barn I would like to convert to a house / garage combo. Columns are 20’ on center in the front and 10’ O/c in side and back. (Pics attached). Is this doable in Ky and roughly cost per sq ft.? We plan on 3 bed, 2 bath, open concept, 40 x 50 living and 40 x 50 garage. Thank you for your input / knowledge. JIM in FRANKLIN

DEAR JIM: Pole barns for agricultural use are rarely designed by a Registered Professional Engineer and in many cases do not require a Building Permit. If it did happen to be both of those things, it was probably designed to a lower set of design standards than a residence would be. Is it doable? Perhaps, however it may cost so much to upgrade your existing building so as to make it financially unrealistic. If you want to pursue this avenue further, it would be best to invest in services of a competent local Registered Professional Engineer who can do a physical examination of your building and make detailed recommendations as to what it would take to make necessary structural upgrades.

Your best solution might be to erect a new building properly engineered to residential requirements.


DEAR POLE BARN GURU: I have a newer pole barn, 30 ft wide, standard trusses 10ft. above the floor. What options do I have to raise the clearance to 14ft? Trusses with a kick up, add a knee wall, scissor trusses? Would prefer whole area at 14ft but could consider just the center 12 ft or so to accommodate a travel trailer. RON in MANISTEE

DEAR RON: It could be possible to increase height of some or all of your building however it will take some significant structural engineering (as well as a serious investment of labor and materials) in order to do so – a competent Registered Professional Engineer should be engaged to visit your existing building, do an analysis and provide a design solution. My educated guess is it will prove to be less expensive to erect a new post frame (pole barn) building to fit over your travel trailer, than to make an attempt to remodel what you have.

pole spacing

DEAR POLE BARN GURU: Builders in the northwest Ohio area don’t seem interested in building a pole barn house with a concrete slab. They said not a good idea do to cracking but there are all sorts of commercial pole barn facilities built on concrete pads. Couldn’t I just use fiber in the concrete to help with expansion? MATT in ARLINGTON

DEAR MATT: Your top factor for getting a good result from a slab on grade concrete slab in a post frame (pole barn) home is proper site preparation. (Read more beginning here: https://www.hansenpolebuildings.com/2011/11/site-preparation/) Just adding fibermesh to your concrete mixture is unlikely to be a satisfactory solution unless you have a great site prepped.

For a pole barn house, you might want to consider building over a crawl space – investment is probably fairly similar, however wood is so much more comfortable to live on.




North Carolina Students Learn Post Frame Construction

North Carolina College Students Learn Post Frame Construction

The following article by Dan Grubb appeared first in the December 5, 2018 Sampson Independent

“Sometimes the building blocks to success look more like beams than blocks. Students at Sampson Community College’s Building and Construction program know this first hand as work continues on a facility the class is building on campus.

“Every day that we can put equipment into the hands of these students and let them go out and build things, the closer we are to them seeing a successful career, “says Dustin Hatcher, Building and Construction Instructor at SCC. “We allow the students to work from top to bottom, start to finish—the entire project. This building will be used as a storage unit for the college’s Maintenance department. This is something they can go to an employer with and say ‘Hey, I’ve done this!’”

This week, students installed engineered wood structural beams onto posts that will be supporting the roof trusses of the building. They are learning how to set up and move scaffolding platforms and accurately measure, mark, then cut the beams with saws and fasten beams in place with nail guns. This provides experience working from elevated platforms and the use of some of the most common tools used in framing carpentry.

The Building Construction Technology curriculum at the college is designed to prepare individuals to apply technical knowledge and skills to the fields of architecture, construction, construction management, and other associated professions. Graduates will qualify for entry-level jobs in architectural, engineering, construction and trades professions as well as positions in industry and government. The course offers instruction in construction equipment and safety; site preparation and layout; construction estimating; print reading; building codes; framing; masonry; heating, ventilation, and air conditioning; electrical and mechanical systems; interior and exterior finishing; and plumbing.

Employment of these types of positions are projected to grow 12 percent from now until 2026, faster than the average for all occupations.”

Mike the Pole Barn Guru adds:

Although this particular project does not happen to be a Hansen Pole Building, we do work closely with interested high schools, colleges and universities in support of Building and Construction or Vocational Education programs. For more information on how you and your school can participate: https://www.hansenpolebuildings.com/2016/01/high-school-classes/.


Building Site Preparation

I’m a Bit Confused…
No, not me – one of our clients who is about ready to invest in his new Hansen Pole Buildings’ Post Frame Building kit. Just like me, when I have something new on the way, Phil is chomping at the bit to be doing something! Anything!
DEAR POLE BARN GURU:  I’m trying to find a step-by-step guide in here somewhere. 🙂
I’m clearing off the topsoil next week, and I plan on digging the post holes soon after. Two questions: What should the diameter of the holes be? Do I lay out the gravel foundation before I do that? I’m a bit confused. (VIDEOS would be great!) Thanks PHIL in LOUDON

DEAR PHIL: After your order is placed, you will have immediate access to the online version of the Hansen Pole Buildings’ Construction Manual. You will also receive a printed copy of it in the mail, soon thereafter. In the meantime, here is an excerpt from Chapter 2 which should help with your site preparation:
To allow proper drainage plan to keep building grade higher than surrounding site. On an ideal site, water drains naturally away from building. Since few sites are ideal, in most cases, grade work will be required to keep surface water away from building. Keeping finished building floor higher than the surrounding site reduces flooding chances during heavy rainfall or rapid snowmelt.
In flood plains, consult first with your building department to determine their requirements. Typical recommendation is to establish grade level at finished floor top higher than flood level. This may require importing fill to raise grade. A surveyor can be hired to expertly determine these heights. In some cases, vents may be installed, below flood level, to equalize interior and exterior pressures,
Many sites can be graded with a skid steer (a.k.a. Bobcat) or backhoe. Some cases will require heavy equipment to properly grade site to allow water to drain away from building. If a professional is engaged for site grading, make certain finished grade prepared is adequate before making final payment. In far too many cases “flat” sites which are out of level have been experienced by disappointed owners.


At a minimum, site preparation includes:
· Remove all sod and vegetation.
· For ideal site preparation, remove topsoil and stockpile for later use in finish grading. In frost prone areas, remove any clays or silty soil
from within the future building “footprint”.
· Replace subsoil removed from around building with granulated fill to help drain subsurface water from building.
· Distribute all fill, large debris free (no pit run), uniformly around site in layers no deeper than six inches.
· Compact each layer to a minimum 90% of a Modified Proctor Density before next layer is added. Usually, adequate compaction takes more than driving over fill with a dump truck, or
earth moving equipment.
· When any building portion sits on fill, rest columns, as well as any concrete encasement, on or in undisturbed soil. In many cases, building inspectors will require a soils engineer to
confirm compaction adequacy on filled sites. Soils engineers can be expensive, but are even more costly when called in to do analysis “after the fact”. Our Building Engineers are
unable to visit sites, therefore they cannot perform or provide any soils or other similar reports, design retaining walls or any other work beyond the building shell.
Be certain to know local Building Department requirements before starting to move dirt.
In many jurisdictions, a separate grading permit may be required. In some cases soil may not be allowed to be moved until after a building permit has been issued. Get started on the right foot with permit authorities – ask first before digging!
Also, prior to doing any excavation call 811. This is a free service to mark underground utilities. Property owners and contractors can be held financially liable if they fail to locate underground utilities (like gas, electric, telephone, cable, water) and damage them in any way (not to mention potential for severe injury or death).
Grade actual building “footprint” area as level as reasonably possible. A grade change beyond eight inches will often result in having to acquire longer building posts.
Grade change is ideally checked before placing building order, however this is not often feasible as a practical matter. If grade has not been checked before order placement, do so within 24 hours. Longer posts are far more economical when provided with original lumber delivery. In some instances, building posts have been specially ordered (due to dimension, length, treating specifications or a combination) and cannot be returned to original producer for credit, even if they have not yet been delivered to jobsite.
Create an adequate work area. At a minimum clear at least 10 feet beyond each building side. Grade the area beyond building perimeter away from building with a minimum 5% slope to drain surface water away in all directions. A 5% slope is a six inch drop in 10 feet.
I would encourage you to do all site preparation, other than the final layer of compactable rock which will be directly below your concrete floor, prior to digging holes.

In the week or so following your order placement, your building plans will be drafted. You will receive a pdf version through your on line login to our website, which will include a page with all of the column locations as well as diameter of the holes. You will be able to print this, in advance of receipt of your engineered plans via mail. In the case of your particular building (subject to final engineering review), it appears all structural (roof supporting) column holes will be 40 inches in depth. The double truss bearing column holes along the eave sides will need to be 24 inch diameter, while the balance will be 18 inch diameter.
Have fun, Phil!

Moby Dick Was Not the Great White Swale

Call me Ishmael.

WhaleSome years ago—never mind how long precisely—having little or no money in my purse, and nothing particular to interest me on shore, I thought I would sail about a little and see the watery part of the world. It is a way I have of driving off the spleen and regulating the circulation.

Opening line of Moby Dick, Herman Melville, 1851

Swale, whale….what difference does a few letters make? Well, if they involve the area around a new commercial pole building requiring swales, it could amount to a whale of a cost!

What is a “swale” anyway?

Grassed infiltration swales (“swales”) are depressions (collection areas) in which storm water from roofs, streets and driveways is collected following a rain or snow event. Swales are used to collect and dispose of storm water runoff, and to remove pollutants from storm water before it reaches underground sources of drinking water. Within a swale there is typically an elevated grate (four to six inches above grade) which is the cover for a drywell. The drywell receives overflow from the swale in the event of excessive runoff. Storm water enters swales through cuts in the curb or through catch basins and infiltrates through the grass and soil. Pollutants in the storm water are removed by the grass and soil in this infiltration process, helping to protect ground water sources from contamination.

Why is a swale necessary?

Drainage swales rely on the infiltration process, which is when water “soaks” into the ground and eventually recharges groundwater. The infiltration process requires the soil to have pore spaces for the water to pass through. Some ground materials have larger pore spaces than others, for example gravel is very effective for allowing water to pass through. Clay soils have small pore spaces which limit the amount of water which can pass through.

Requirements vary from jurisdiction to jurisdiction, however this overview gives an idea of what is entailed.

How do you design a swale?

The depth from the swale floor to the top of drywell grate must be no more than 8 inches, but deep enough to accommodate the designed volume of runoff. Following a storm event the swale should not have standing water for more than 72 hours. The floor of the swale should be level to evenly distribute water throughout the swale. The drywell should not be placed near the inlet to the swale. Drywells should be installed according to the approved plans.

Developing a good swale

Do not drive over swale area prior to construction. Compaction of soils will dramatically reduce infiltration. Shallow bedrock under the swale area will prevent percolation and infiltration, significantly reducing the performance of the swale. Importing top soil or sand will create a layered subsurface which is not conducive to good infiltration. Onsite top soil should be used in swales whenever possible. When off-site top soil/sand is used it should be mixed with two inches of organic matter per six inches of top soil and rototilled into the existing surface. This will greatly increase the infiltration capacity of the swale. Do not clean concrete truck chutes, masonry tools, and painting equipment in or near swales. These materials will dry and produce a layer of impermeable material which can destroy the infiltration process.

Sod is not the only option for establishing grass in swales. Hydroseeding is becoming more and more accepted. Recommendations for seed mixes are moving to grass species which are able to establish in poor soils and have a high drought tolerance. For aesthetic purposes, drought tolerant species are being utilized in areas which do not require turf. Sod should be fresh and after being placed should be kept damp for 2-3 weeks to encourage rooting.

How to protect a swale

 Erosion on construction sites occurs when cleared and graded slopes are not protected from the erosive forces of rain fall and runoff. Frequently, there are no measures taken to protect infiltration swales from the deposition of the sediments in runoff. This results in a fine layer of silt that clogs the bottom of the swale. Slopes which have been graded must be protected from erosion. Inlets to the swale should be protected from runoff carrying silt eroded form the site.

Drywells in the swale should be protected from sedimentation by placing filter fabric under the grate.

Pole Barn Guru’s Swale Experience

 My first personal swale adventure was when I developed about three acres of land and constructed an 80’x150’ pole building for fabricating roof trusses. Most of the property was covered by either the building, or paved areas for parking and lumber storage.  The engineered site plan was deemed necessary to account for a great deal of storm water runoff. The required swales were so large, I was sure we could have floated the Pequod in at least the largest of them!  The soil was so sandy, I was personally sure if you dumped a cup of water on the ground prior to the installation of the swales, it would have been in the aquifer in an hour. However, bound by the planning department, I had no choice.

And for their cost, I could have bought a replica of the Pequod – between the engineering, the excavator, drywells, special soils and sodding….everyone had their hand out.