Tag Archives: stud walls

Wide Clearspan Barndominium Floors

Wide Clearspan Barndominium Floors
Multi-story post frame barndominiums are embracing a great feature found in better stick framed homes – engineered prefabricated wood floor trusses.
Loyal reader RICK in MONTICELLO writes:

“First off, thanks for sharing your knowledge and experience in the blog and answering questions regarding post frame construction with us laymen!
It is very educational and enlightening.

Kicking around ideas currently. Have a 50ish x 80ish building in mind.
And since you suggest working in 6 foot multiples. We’ll go with a 54′ x 84′ two story building.

Thinking about 12′ clear inside height grade level and living upstairs (actually a lake house so to speak).
You mention you have 48′ free spanned with floor trusses.
I’m curious how deep they are and what centers they are installed at.
As I’d like to clear span the 54′ if possible.

My questions and curiosities are:
• You aware of any fabricated wood floor trusses spanning longer than the 48’ you have?
• Would the floor trusses be prohibitive, as far as cost and losing a lot of height due to the required depth they would need to be?

If I free spanned the whole building at 12” centers I’d need 82 of them.
Working from an assumption they would have to be on 12” or 16” centers raises the below questions:

• How is this done in post frame?
• Would I require regular stud walls between each post that first 12’ of building height for the floor trusses to rest upon to transfer the loads to the ground/ foundation?

Hopefully not too lengthy.

Thanks in advance”

Mike the Pole Barn Guru says:
Thank you very much for your kind words, they are greatly appreciated.

With typical residential live loads of 40 psf (pounds per square foot) and dead loads of 10 psf, normally floor trusses are spaced every two feet and their depth will be roughly an inch per every foot of distance spanned. 54 foot clearspan is certainly well within range of prefabricated wood floor trusses.

Even with all of my years as a manager of owner of truss plants, 48 feet is as wide as I have participated in – although for our own personal shouse (Shop/house), we wish we would have gone 12 feet wider (no matter what size you build, it is never big enough). Your added investment, for floor itself, between having a myriad of internal columns, or clearspanning is roughly four dollars per square foot. For what it adds in downstairs usability by not having columns or walls to work around, it is worth every cent in my mind. Add to this it allows for all utilities to be hidden from view and they are a winning combination. As we are providing more barndominiums seemingly every day, we have many clients taking advantage of clearspan floor trusses and have never heard a regret from having done so!

Most usually floor truss ends are supported from beams attached to wall columns. This eliminates having to have load carrying stud walls between columns, as well as thickened slab edges or continuous footings and/or foundations. In order to maintain ceiling heights, your building will have to be made taller. In most instances, adding a few feet to a building’s height is relatively affordable.

Stretching Stick Frame Construction

Post frame (pole building) construction is popular due to efficiencies of materials (ability to do more with less) and speed of construction.

Reader RAYMOND in BARLING is trying to find a way to make stick framing cheaper, he writes:

“24×64 pole barn in question. 4 pitch.  I am just comparing the cost of alternate designs.

Using 2×6 rafters with purlins across top for metal. Can I part from the standard 24 OC of rafters and expand to 30 OC (since more support from purlins)?

Furthermore, is it possible to use 30 OC studs all around, instead of poles (since more support from purlins on walls)

I would really appreciate your wisdom.

Thanks!!”

Mike the Pole Barn Guru says:

Let’s begin with, “since more support from purlins on walls”. Studs in stick framed walls will not resist wind loads perpendicular to a wall any better due to lateral support from purlins (actually girts) installed horizontally.

Your rafters are also going to be unable to support greater roof loads due to purlins being attached.

Building Codes have prescriptive requirements limiting what can and cannot be done with conventional (stud wall) framing, without having to have a fully engineered building. This would include studs and rafters being no greater than 24 inches on center. They also preclude wall heights of over 12 feet (you did not mention any heights however it should be kept in mind).

International Residential Code (IRC) Table R8702.4.1(1) provides rafter spans for common lumber species with a roof live load of 20 psf (this happens to be Code minimum whether snow is present or not). Being as you are in Arkansas, we will assume the minimum load as well as no ceiling being attached to rafters. With rafters 24 inches on center your rafters would need to be 2×8 #2 Southern Pine at a minimum. You would also need to provide ceiling joists or rafter ties to resist outward push of rafters on bearing walls. In order to get full value from rafters, ratio of rafter ties measured vertically above the top of stud walls to the height of roof ridge would need to be 1/7.5 or less. At a 4/12 slope ridge height would be 55.64″ meaning rafter ties could be located no more than 7-3/8″ above top of stud wall, so plan on then being at least 20 feet in length. A ridge board must also be provided as well as a collar tie, gusset plate or ridge strap (please refer to IRC R802.4.2).

Stud walls also mean you would need to make provisions for structural headers above any opening in any load bearing exterior wall. With post frame construction openings can be placed between columns in exterior walls, eliminating structural headers (this assumes trusses are placed aligned with wall columns with roof purlins on edge).

For stud wall construction, your concrete slab on grade will need to have an appropriately thickened edge in order to support weight of walls, or a continuous footing and foundation will need to be poured.

Ultimately post frame construction, not stick wall construction, is most probably going to be Raymond’s best route to go when considering investment and ease of construction.

Bookshelf Girts or Stud Walls?

Why Use Bookshelf Girts Rather Than Studs?

Long time readers may recall my Grandpa Pete was a home builder and his sons – Sid (my father), Neil, Lyle, Gil, Dave and Amund were all framing contractors. https://www.hansenpolebuildings.com/2011/06/before-the-pole-barn-guru/. Besides being raised with “wood is good”, I had a concept of vertical stud walls permanently ingrained in my head!

Stud walls led to my losing my posterior erecting my first post frame (pole barn) building. I struggled with this 90 degree ‘flip’ in framing concept far more than I needed to. Luckily, I was able to wrap my head around left-to-right rather than up and down when it came to my second building and I actually made some very good money!

Reader TRENT in WALLA WALLA writes:

“I am currently working on plans for building my first post frame home. It will be 30×48 single story. I am trying to figure out the best wall girt design. I am looking at going with 2×8 bookshelf wall girts or vertical stud walls between the posts. I see more people going with bookshelf girts vs vertical studs. Is there any drawbacks or reasons not to use vertical stud wall framing between the posts?”

Mike the Pole Barn Guru responds:

Installing a ceilingPretty straightforward – vertical stud walls will take more lumber. Besides increased material investment, more pieces mean more connections and more labor.

Imagine, if you will, a pole building with a 10′ eave height and columns every 12 feet. Bookshelf girts take (1) 2x4x12′ pressure treated, (4) 2x8x12′, (2) 2x4x8′ for blocking girts ends and (2) 2x4x12′ to attach drywall at the ceiling level – 98.67 board feet of lumber. For stud walls (1) 2x6x12′ pressure treated, (7) 2x6x10′ studs, (1) 2x6x12′ top plate, (1) 2x4x12′ to attach drywall at ceiling level, (4) 2x4x12′ horizontally to attach steel to wall studs – 134 board feet of lumber. From a structural aspect, care will need to be exercised in attachment of the top plate and end studs to adequately transfer wall bay wind loads to columns. It may necessitate some sort of Simpson strap to properly anchor the plate to columns.

 

 

 

 

Vertical Flush Walls

There is a builder in my neck of the woods who advertises as “the only company around that offers…Vertical Flush Walls, for your pole building, shop or garage, which allows you to sheetrock inside your building without having to re-frame the inside!”

In the photo with this article, wall girts have been placed “barn” style flat on the outsides of the columns, where they would have failed in bending (read why they fail on their own here: https://www.hansenpolebuildings.com/blog/2012/03/girts/).

vertical flush wallsTo me, vertical flush walls look like a stick framed stud wall has been built on the inside, which supports the wall girts and does exactly what it purports to do.

However there is an easier, faster and less expensive method, which provides for an insulation cavity deeper than the adding a second wall inside of the first, bookshelf style wall girts: https://www.hansenpolebuildings.com/blog/2011/09/commercial-girts-what-are-they/

In an typical 12 wide bay of this building, with a 14 foot high eave, to commercially girt a bay and be totally gypsum wallboard framed ready, it would require six 12 foot 2×8 for wall girts, a 12’ pressure treated 2×4, and 4 2x4x12 for blocking and backing. Total Board footage of lumber – 136.

As farmed in the photo shown, materials required are a 12’ pressure treated 2×6, seven 2x6x14 studs and a 2x6x12 top plate. Wall girts are six 12 foot long 2×6. Total board footage – 194, or 42% more lumber. Besides not making economic sense, the concrete slab is also required to be installed, in order to place the vertical stud wall.

Whilst it is wonderful for the builder to have added this interior “liner” wall in, there is something the builder missed, which is pretty important in buildings which will be insulated and climate controlled – building wrap (read more about building wrap here: https://www.hansenpolebuildings.com/blog/2012/11/house-wrap/).

Great sounding marketing ploy, but in reality, just not very effective.