Tag Archives: electrical planning

Electrical Installation, A Frequent “Plans” Question, and Vapor Barriers

This Monday the Pole Barn Guru answers questions about running electrical through posts, a question often received about plans, and vapor barriers.

DEAR POLE BARN GURU: I’m looking for the lvl beam, floor / roof joist and wall purlin penetration layout for plumbing and electrical install.

I will not need many horizontal penetrations. A few for electrical install and the hot and cold water lines

I will need to have vertical penetrations in the wall purlins for the waste and vent lines.

Max hole size

Spacing between holes

Hole location in joist / lvl beams. Upper middle lower?


DEAR GREG: Here is some information from Hansen Pole Buildings’ Construction Manual:

Q: Can electrical be drilled through framing or columns?

A: Very little drilling, if any, will be needed for holes in order to run electrical wires. Wall framing (girts) extend or are placed so as to leave a 1-1/2 inch space between outside of wall columns and siding.

  Think of a hole being drilled through as being an “open knot”. Lumber grading rules refer to these as being “Unsound or Loose Knots and Holes” due to any cause. Most structural framing – like wall girts and roof purlins or posts and timbers are graded as Number 2.

  For practical purposes, a hole up to just less than ¼ of board face being drilled through will be within grade in #2 lumber. Example: 3-1/2” face of a 2×4 a hole up to 7/8” may be drilled through, as often as every two feet. Allowable hole sizes are reduced and spacing increased for higher grades of lumber.

Here is APA’s guide to drilling holes in LVLs:


Engineer sealed pole barnDEAR POLE BARN GURU: Where do I get plans to take to the state to get a permit? DAVID in EDINBURGH

DEAR DAVID: With your investment in a new Hansen Pole Building, we will provide two sets of third-party structural engineer sealed plans and pertaining calculations for your to submit for your Building permit.


DEAR POLE BARN GURU: I have a 40×40 pole barn that is open on one gable end and used for vehicle and trailer parking. I am re-siding and re-roofing with metal over purlins. Do I need a vapor barrier such as roofing felt under the metal? KEVIN

DEAR KEVIN: You should have something to prevent condensation. My first choice for ease of installation would be to order roof steel with dripstop or condenstop attached by roll former. https://www.hansenpolebuildings.com/2014/07/condenstop/

If this is not an option, use a reflective radiant barrier with an adhesive pull strip attached for ease in sealing seams.



Electrical Planning, Moisture Issues, and Ceiling Barriers

Today the Pole Barn Guru fields questions on electrical planning, moisture issues, and ceiling barriers.

DEAR POLE BARN GURU: Good Morning/Evening:     I currently have a 36′ wide x 48′ long with 12′ tall ceiling pole barn that I would like wire for lights and outlets.   I intend to run main power from the street pole to a meter base and into a internal breaker box.  I know you have/sell electrical planning layouts for the internal pole barn light/outlets and I would like to purchase a set for use as a general guide.  Can you tell me how I might purchase your pole barn electrical layouts, etc.??    Thanks for your help in advance.   Very Respectfully. BILL in AMHERST

DEAR BILL: Thank you very much for your inquiry. We do not involve ourselves in any sort of electrical. No electrical materials, no layouts, no plans. Try visiting the ProDesk of your local The Home Depot for assistance.


DEAR POLE BARN GURU: Hi I’m emailing because I’m having issues with moisture in my building it happens when it freezes and then thaws and it only drips from the pillars and I have moisture barrier inside can you please explain why that’s happening. ROBERT in CHEHALIS

DEAR ROBERT: We receive a handful emails with challenges such as yours every winter, from clients who recently had their buildings completed. It all goes back to where is moisture source?

If no concrete slab in your building, it is because ground outside of your building freezes before ground inside. When this occurs it is like pulling a cork from a bottle – all ground moisture from area surrounding building tries to escape through your building.

Have a fairly new slab on grade in your building? Moisture will be coming from it. As long as you have a well-sealed vapor barrier under your slab, you should only experience this issue for one winter. You can speed this process along by keeping large door(s) open on days when dew point stays lower than outside air temperatures (lower humidity, faster water will exit your slab).

If a well-sealed vapor barrier was not installed under your building’s slab, then slab surface should be sealed (once it dries out).


DEAR POLE BARN GURU: Hello. I plan to use foil backed foam sheets for my ceiling in my 28 x 34 Pole Building / garage. Reading your article, you would NOT put up a plastic barrier to control heat loss before hanging the Foam board? 4 / 12 pitch. Recommendation for hardware to secure sheets to trusses?
Thank you DAN in BUTLER

DEAR DAN: A plastic barrier would not make any difference in controlling heat loss, as it has no insulating value. Your foam board, if installed properly with joints sealed, will act as a vapor barrier. I’d glue it to truss bottoms to eliminate transfer of heat through nails or screws. Make sure to adequately ventilate dead attic space you are creating and a provision for preventing warm moist air from contacting roof steel underside exists.