Tag Archives: polycarbonate roof panels

How Deep Should Pole Barn Holes Be?

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

ask-the-guruDEAR POLE BARN GURU: I am concerned that my plans might not have my pole barn holes going deep enough. The person I have hired to drill the holes for me has had a couple bad experiences with ‘frost heaves’ in our area, specifically when he didn’t go at least 4 feet down. My plans call for a 42″ depth for the pole barn holes, and the post going down only 34″. I would like to go down as far as possible with my posts, but obviously don’t want to be short on the top. Can you please take a look at my plans, and tell me what my maximum post depth would be? Thank you. JOE IN TAYLORS FALLS

DEAR JOE: Frost heaving is certainly a valid concern in areas of the country where deep freezing can be an issue. The requirements for frost depth are one of the items we have every client address, when they have their Building Code and load information verified by their Building Department prior to ordering their new Hansen Pole Building kit package.

I’ve written extensively on frost heave, as well as what to do, or not to do here: https://www.hansenpolebuildings.com/2013/11/frost-heave/

For your state, Minnesota, the Minnesota Department of Labor and Industry has available a frost depth map: https://www.dli.mn.gov/ccld/pdf/bc_map_frost_depth.pdf

SquareFoot™ concrete footing forms has a frost depth map for the United States: https://soundfootings.com/pdf/US_Map_Frost_DepthAVG.pdf

In your particular case, with a perfectly level site, you could have the pole barn holes as deep as 56″, which places the bottom of the columns at 48″ below grade. The key word being “perfectly level”. It is acceptable to dig the holes deeper yet, and increasing the depth of concrete below the column.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I have a pole barn built in 1971 by Moriarty. My FRP Skylight has deteriorated and rotted off do I have any options other than replacing the whole roof, no one seems to be able to match the rib pattern.



Over the years there has been a consolidation of steel roofing and siding profiles, to the benefit of all involved except those who have older buildings with more unique rib patterns (like yours may very well be). Skylights (whether FRP or Polycarbonate) should really be avoided in the roof plane as they are not designed to withstand horizontal wind loads.

Some choices (other than entirely replacing the roof) – replace the areas of FRP with new steel panels which have the same net width coverage. Obviously the colors will not match, so you may consider using an entirely different color as an accent panel. Or, send us photos and measurements which will clearly delineate all dimensions. While we cannot recommend this as a structural solution, if our polycarbonate manufacturer can match it – it does afford a solution.

For more reading about old skylights: https://www.hansenpolebuildings.com/2014/09/skylights-2/

Mike the Pole Barn Guru


My husband and I are considering on building a pole barn house. The one question we currently have is: How would the house stand up to our Canadian weather? We live in Saskatchewan where the weather can drop to -55c in the winter. Thanks TRINITY IN TISDALE

DEAR TRINITY: Good for you and your husband for considering a pole barn house. Regardless of whether your weather is extreme cold or heat, post frame (pole) building construction can prove to be very energy efficient. Roof systems can be created to allow for R-60 or greater insulation depths and wall cavities can be designed to meet any desired insulation thickness.

In most cases wall and roof systems can be designed to minimize thermal bridging.

Mike the Pole Barn Guru

How to Replace Skylights

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 have fiber glass roof light panels and they are leaking and damaged. I need new skylights. They have to match my old steel panels. Do you know where I can get some? HICCUP IN HINCKLEY

DEAR HICCUP: This is an ongoing issue with people who used fiberglass panels in roofs for skylights. The information you are seeking maybe found by reading: https://www.hansenpolebuildings.com/blog/2014/09/skylights-2/

Mike the Pole Barn Guru

DEAR POLE BARN GURU: Do you sell just the large rolling track style doors? AIRY IN ALASKA

DEAR AIRY: Although our prime business is providing complete post frame (pole) building kit packages, we can supply just the components for sliding doors. We are happy to help you – Please be aware – there will be a considerable amount of freight in shipping a sliding door package to any location, and even more so in your case – Alaska. Please send any sliding door package assembly requests to Eric@HansenPoleBuildings.com

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I’m planning on having a pole barn built to be used as a shop building for my business. I want to insulate the roof and walls. The walls are easy, but I am not sure how to economically insulate the roof. The roof is supported by a pair of trusses bolted to each side of the pole (actually a 6 by 6 pressure treated post). Purlins are 2 by 6’s placed 24 inches on center, running parallel to the ridge. There is a vapor barrier “insulating blanket” (really very thin) on top of the purlins under the steel roofing panels. It is there to prevent condensation and subsequent raining inside the building.

One idea would be to nail 2 inch thick foil faced foam panels to the underside of the purlins, then 1 by 3 strapping nailed 16 inches o.c. perpendicular to the purlins, to create a three-quarter inch air space between the foam panels and the half-inch drywall nailed to the strapping. I’ve specified the roof be built to support the weight of the drywall.

Do you have better and or cheaper ideas? WANTING IN WASHINGTON

DEAR WANTING: Although it has little to do with insulating your building, I’ll start with a structural concern – instead of placing trusses on each side of the columns, I would recommend they be nailed face-to-face without blocking between, then placed into a notch cut into the tops of the columns. The trusses then actually act as a pair, as opposed to two individual trusses spaced apart. This greatly reduces the possibility of a catastrophic failure due to one individual truss failing, as the probability of the two joined trusses having the exact same weak point is infinitesimally small.

Moving forward – typically columns (and trusses) in your part of the country are spaced every 10 or 12 feet. If 2×6 roof purlins are to be used, they will not be able to carry the weight of the drywall without undue deflection.

Let’s go to simple, better and easy. In your proposed version, a large area is being created above the plane of the bottom chord of the trusses and below the drywall – where all of the heat is going to rise to. You will have to heat a large volume of space, which is not able to be utilized.

Instead – specify the trusses to be fabricated with a raised heel (see https://www.hansenpolebuildings.com/blog/2012/07/raised-heel-trusses/). Install 2×6 ceiling joists at 24 inches on center between the roof truss bottom chords, using a Simpson LU24 or similar hanger at each end. Install 5/8” gypsum wallboard across the underside of the ceiling joists. Blow in cellulose or fiberglass insulation, or use unfaced batt insulation above the drywall.

Be sure to include specifications to ventilate the dead attic space: https://www.hansenpolebuildings.com/blog/2014/02/pole-building-ventilation/

These steps will allow you to climate control the least amount of space, with the least cost to achieve the insulating system.

Mike the Pole Barn Guru