Tag Archives: polycarbonate skylights

Fiberglass Panels, Accurate Info, and Truss Bracing!

DEAR POLE BARN GURU: I have four skylights with old fiberglass panels that are in need of being replaced. I doubt the design of the panel can be matched easily but am wondering if I send you a piece of it if it can be. I understand the way to go is with a polycarbonate, not fiberglass, panel. Thanks DAVE in BAY

DEAR DAVE: As you are finding out, skylights are problematic. Here is some extended reading on why: https://www.hansenpolebuildings.com/2012/01/skylights/.

If indeed you determine the only solution is to replace fiberglass panels with polycarbonate (me, I would replace them with steel panels and be done with the future headache) I would recommend a visit to the ProDesk at your local The Home Depot® as they can order in most anything and it usually comes in freight free, which can prove to be a significant savings.

DEAR POLE BARN GURU: I am buying a building immediately but your website is too intrusive to shop, so I will not be using you. I, like many others, do not like the setup for quotes because in most cases you turn into used car salesmen. BRAD in KNOXVILLE

DEAR BRAD: Thank you very much for your input. In order to be able to provide accurate pricing and design advice to our clients, we do need to gather some basic information. Things like where is your new post frame building to be constructed (so we get the correct climactic loading conditions), as well as how do we best reach you to discuss your proposed project. We get several hundred new inquiries each day, seven days a week, and frankly you are the first to voice an opinion as to our website being intrusive. If you have constructive solutions as to how we can best glean the information needed to be able to best provide our services, without coming across as being ‘intrusive’ we would welcome your input, as we always strive to improve.

Our Building Designers are highly trained professionals whose mission is to assist our clients in the quest for the ideal dream building which melds imagination, budget and available space. Post frame buildings are highly involved, engineered structures, which ideally require a fair amount of interaction between us and the client to arrive at the best design solution. We do not “sell” anything to anyone – we provide the assistance to our clients, as well as the education which enables our clients to invest in The Ultimate Post Frame Building Experience™, should they decide we are the best fit. Most of our clients have spent hours perusing the thousand plus pages of free information on our website and have decided they are going to own a new Hansen Pole Building long before they ever request a quote.


DEAR POLE BARN GURU: Question about my plans. On the drawings, my purlin spacing is noted as 31” OC. On the truss drawing, I see that it says the bracing for the top chord is 24” OC. Am I reading this correctly? 

It states: 

(Switched from sheeted: Spacing > 2-0-0).

and then below it talks about the Bottom Chord: Rigid ceiling directly applied or 6-9-13 oc bracing. What does that mean?


DEAR DAN: Truss drawings are designed without any knowledge of how a particular building is constructed, or what the final bracing system for the entire structure is – the permanent bracing design is left to the engineer of record (see General Safety Notes #2).

You will note the top chord bracing says 2-0-0 purlins then says the maximum spacing is 4-7-0 (least of the three drawings). The 31″ spacing on the plans is far less than the 55″ maximum.

Bottom chord bracing is a function of a maximum L/d (length divided by depth) ratio of L/80 for members in tension (truss bottom chords are in tension as they are preventing the walls of the building from going out). The width of a single 2x member is 1.5″ X 80 = 120″ maximum for a single width 2x member. You will note on the endwalls of the building there is a 2×4 nailed to the face of the bottom chord of the truss. This now makes the member three inches in width so technically it could be braced once every 240″ (or 20 feet). The same goes for the interior double trusses, the three inch width member is good up to 20 feet without being braced laterally.



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