Tag Archives: holes for electrical wires

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?

Thanks, GREG in LEAVENWORTH

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:
http://murphyplywood.com/pdfs/engineered/APA_LVL_Hole_Drilling.pdf

 

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.

 

 

The Hole Enchilada: Electrical Holes

EnchiladaOne of our clients purchased two pole building kits from Hansen Pole Buildings last year. He has the first one completed (he constructed it himself), and decided to hire a contractor to complete the second one for him.

The Hansen Pole Buildings Designer, Rachel, contacted him recently, to see how it was progressing. The client did pose an interesting question to Rachel:

“Can I drill holes into the poles for electrical and plumbing, if so how big is allowable, and how many per pole.”

Good question and one which will pertain to any form of wood frame construction – not just post frame.

One of the beauties of post frame construction is typically very little drilling, if any, is needed for electrical holes in order to run wires. Why? Because the wall framing (girts) extend or are placed so as to leave a 1-1/2 inch space between the outside of the wall columns and the siding (whether steel or most any other type of siding).

The IBC (International Building Code) and IRC (International Residential Code) do not spell out the allowable size and frequency of holes which can be drilled through structural wood members. In order to find the answer – it takes digging into the standard lumber grading rules.

Think of a hole being drilled through, as being an “open knot”. The lumber grading rules refer to these as being “Unsound or Loose Knots and Holes” due to any cause. Most structural framing (whether joists and planks – like wall girts and roof purlins or posts and timbers) is graded as Number 2.

For practical purposes, a hole up to ¼ (or just less than ¼) of the face being drilled through will be within grade in Number 2 lumber. Example: If you have a 2×4, the face is 3-1/2” across – so you can drill a hole through that face up to ¼ x 3-1/2” or 7/8”. That’s a pretty good sized hole.  The hole size is reduced for higher grades of lumber (think of it as higher grades – fewer allowable defects). In Number 2 graded material, a hole is allowable as often as every two feet (again holes must be spaced further apart for higher grades of lumber).

On a stick framed building, assuming studs every 16”- you would need to drill through every one of them for electrical holes.  With a pole building, you can just run your wiring around the post (between the post and the siding) and between the girts – so you should be able to avoid drilling any holes.

To answer the question for plumbing – you are not supposed to drill holes through a post larger than what is allowed. As long as they are small enough in diameter, you could run hot and cold pipes through it.  Again – to do this in an exterior wall is questionable.  I’d check with your local building department and get their verdict on it.  To run a waste line (larger diameter) through a post – you’d have to use larger framing in the wall, or furr in a wall to do it.

While I try to drill as little as possible (it takes more effort and tools to do so), the Code does allow for them, within reason.