Tag Archives: 6×6 columns

Switching Post Sizes, Structure Length, and Fire Damage

This week’s ask the Pole Barn Guru answers reader questions about switching post sizes from a 6×6’s to 6×4’s, how long a structure can be built with 15 trusses with 2×4 chords, and if it is possible to rebuild on a slab that was part of a fire loss.

DEAR POLE BARN GURU: I am about to buy my post for a residential post barn using 6 x 6 x 12 post in Sottsburg, Indiana. A neighbor suggested instead of using 6 x 6 x 12, to use 4 x 6 x 12 in substitution for some of the post that would be none corner or door support post. My question would be can it be done and meet building code being it will not have an attack or vaulted ceilings? LEVIA in SCOTTSBURG

DEAR LEVIA: In most instances a 4×6 #2 will be stronger than a 6×6, however switching out columns should only be done with approval from your engineer who sealed your building plans.

For extended reading on this subject: https://www.hansenpolebuildings.com/2019/04/when-size-or-lack-thereof-matters/


DEAR POLE BARN GURU: 2 x 4 Truss spacing question, how long do you advise to build a Pole barn with 15pcs of 2 x 4 x 24′ engineered trusses? 🙂 The fires got 8 of them so I’m refiguring my length, but wanted some help on the truss spacing? Thanks, MARSHALL in PORTLAND

DEAR MARSHALL: The engineered truss drawings will provide maximum on center spacing of trusses. With 2×4 chords, I would suspect this to be 24 inches. With 15 pieces, you could build a 28 foot length building.


DEAR POLE BARN GURU: I’m working on a fire loss to a post frame building that was converted to multi-unit apartments. The building shell is post frame on slab with interior walls framed. My question is could we demo the building saving the slab rebuild utilizing standard residential stud wall and truss framing. Thanks CHRIS in FLOYDS KNOBS

DEAR CHRIS: Heat from a fire can result in concrete chemical composition breakdown. Other effects include concrete spalling, seen as large pits. Concrete may have protected substrates below, but further investigation is probably required. Water used on fire can also adversely affect soils below. Have an engineer familiar with concrete test for strength. Sometimes it may look like concrete is okay, but then later it begins to crumble.

Outside of this, slabs for post frame buildings do not have continuous footings and stem walls, or edges thick enough to provide protection from frost heave and to support imposed loads from building dead weight and imposed loads.


When Size (or Lack Thereof) Matters- 4×6 Columns

Prior to Hansen Pole Buildings’ client’s plans being sealed by our third-party engineers, their preliminary plans are uploaded for client review through a login. While review goal is to make certain everyone is working from a same left and ensure doors and windows are properly located, it does trigger some interesting discussions at times.

Here is a recent email received from one of our clients in Ohio:

“Just had the chance to look through the plans. Was surprised to see 4x6s on the corners of the main building. What is the rationale for that? If it’s simply cost savings, can I pay extra to have 6x6s in those 4 places?”

Here is my Pole Barn Guru response:

Prior to verifying the larger dimension (albeit weaker) member might work, this may prove valuable reading:

From the Hansen Pole Buildings Construction Manual:

Why might corner columns be smaller sized? Each building column carries a load equal to ½ distance to next column on each side!  This means corner columns are carrying about ½ other column’s loads. Further, on an enclosed building, corner columns are braced in two directions by girts and wall steel (or other sidings).

Why might a building have 4×6 columns, rather than 6×6? As mentioned in lumber defects section (Page 37), 4×6 lumber and 6×6 lumber are graded under different “allowable defect” categories. 4×6 material is held to much more stringent guidelines. As an example, if allowable defects from a 4×6 #2 grade, were applied to a 6×6, 6×6 would have to be graded as Select Structural. Conversely, if allowable defects from a 6×6 #2 grade were applied to a 4×6, 4×6 would be less than “utility” grade.

These allowable defect characteristics follow through to design values used for structural calculations. Without getting overly technical, 4×6 #2 Fb (fiberstress in bending) value is nearly double 6×6 #2 value.

As well as: https://www.hansenpolebuildings.com/2014/08/lumber-bending/

In the event you still wish a material change, please contact Materials@HansenPoleBuildings.com.

Post frame efficiency is achieved by every member and connection being checked and verified for ability to carry imposed loads. Software utilized by Hansen Pole Buildings and our third-party engineers verifies complete structural adequacy in all cases.