Tag Archives: floor trusses

Multi-Story Pole Barns

Multi-story Pole Barns
Hansen Pole Buildings has developed a reputation for taking potentially challenging post frame (pole barn) building projects and developing them from concept to fruition. This leads many clients, with an interest in multi-story pole barns, to our doors.

Gambrel roof pole barnMy own post frame building home, along Lake Traverse South Dakota side, features both a second floor and a mezzanine (partial third floor) where my lovely bride has her sewing and quilting projects in various stages of assembly.

Our house Northeast of Spokane has two multi-story post frame buildings. Both of these happen to be constructed upon sites with a significant grade change. One of them has a 22’ x 24’ garage, with a studio apartment below and an office above (located in attic bonus room trusses). Tallest of these has been located near property rear. 40’ x 36’, it has a three vehicle garage space in lowest level, a full second floor, as well as a third floor (and a rooftop deck).

More reading about this building can be found here: https://www.hansenpolebuildings.com/2012/02/grade-change/.

Reader K.F. in ONTARIO writes:
“I would like to build a pole barn with a 10’ lower level and an 8’ upper area, with the dimensions 30×48. I would expect that the poles would need to be around 19-20’ long (above grade). That seems like a very tall pole (3x-2×6). What is the best way to build two levels and how does the upper floor go in?”

In my humble opinion, multi-story post frame buildings should always be designed by a Registered Design Professional (RDP – architect or engineer). Risks are far too great for an average person to safely and competently design a multi-story pole barn.

As to heights, one needs to look to how they desire to best utilize spaces being created. If interior columns are not an issue, a floor thickness of around a foot should be allowed for between levels. Don’t like having to maneuver around posts? Then floor trusses (https://www.hansenpolebuildings.com/2017/01/wood-floor-trusses/) might be a design solution. Roughly allow about an inch of truss depth for every foot of floor being spanned. Obviously, higher than residential weighted floors will necessitate a need for greater truss thickness.

Many multi-story post frame buildings are used residentially. If your proposed building will be climate controlled have roof trusses designed with raised heels (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/) in order to provide full thickness of insulation from wall-to-wall. In colder climates, with a R-60 attic insulation recommendation, raised heel trusses could be as deep as 22 inches!

With a clearspan floor and raised heel roof trusses, ceiling heights desired by K.F. could result in sidewall heights of over 22 feet.

Not to fret – glu-laminated technology has allowed for one piece columns to be manufactured up to 60 feet in length. My own South Dakota building has columns as long as 50 feet.
As to how an upper floor goes in, this is where RDP experience comes into play. I have witnessed far too many instances of poor design practices of second floors without an engineer’s knowledge involved.

Looking for a multi-story pole building? Look to a post frame building kit supplier who works with a RDP to provide engineer certified plans for your building. Much better safe and standing, than flattened.

Pole Building Rooftop Decks

Post Frame Roof Top Decks

Question: Can decks be constructed upon a post frame roof top?

Answer: Yes, and it may prove far simpler than one might expect.

Our typical request from clients generally revolves around having a very slightly sloping roof and to use EPDM (ethylene propylene diene monomer) rubber as roofing over plywood. This solution might work, however very slight slopes tend to be problematic.

One of my own post frame buildings, located lakeside at Newman Lake, Washington, happens to have a rooftop deck. This particular building’s location happens to be perched upon the rear (farthest distance from our lake front) of our steeply sloping lot. The 30’x36’ building with a 10 foot wide enclosed shed off left sidewall has a total footprint of 40’x36’.

This building happens to be tall. Very tall – as in 40’6” from grade to roof peak. Besides garage level, it has two floors above. Upper floor clearspans a 30 foot width with floor trusses. This level also has a vaulted ceiling, provided by scissor trusses (I’ve written about this particular building’s roof trusses previously: https://www.hansenpolebuildings.com/2018/08/post-frame-scissor-trusses/).

Smoky MountainsKnowing this building would be very tall, and there would be a 180 degree panoramic lake view, it was planned all along to have a rooftop deck.  Adding to design challenges, we wanted this deck to be capable of supporting weight of a hot tub and its occupants!

This deck would cover an area between pairs of roof trusses/sidewall columns, a space of 12 feet along the building length. Sidewall columns were extended through the roof steel, to support glu-lam beams. These glu-lam beams had their opposite ends supported by a roof truss system designed to carry concentrated deck loads (along with snow and ceiling loads).

Where columns and glu-lams penetrated roof steel, a thick, high quality rubber and acrylic elastomeric roof coating formulated especially for steel roofing was used. After over 20 years of service, no leaks have been experienced. Other solutions may have been to use EPDM rubber boots and flashing to seal penetrations.

Interested in roof top entertaining upon your future pole building? It can be done, just ask your Hansen Pole Buildings’ Designer.

 

Friends Don’t let Friends Stick Frame

Oh the misconceptions arm chair engineers have when it comes to what can be done with post frame construction. For the most part – if you can imagine it, we can design it! Here is a case in point shared by our friend Neil:

DEAR POLE BARN GURU: I have limited floor plan on my lot, looking at a 24w x 64L size post frame building, 14 or 16 foot open height workshop area for lift and heavy truck work and a full second floor for an office, light storage, etc, (40psf live load). This would put the sidewalls between 20 and 22 feet. I believe I can clear span the 24 feet with modern engineered joists, but at this point does it still make sense to use post frame construction? Friends of mine have concerns about column loads, footing capacity, and suggested to just pour a full foundation, stick frame with it to 16′ and build a second floor and go up from there and put trusses on. NEIL in CLEVELAND

DEAR NEIL: Not only is post frame construction going to be the most practical solution, it will also be the most economical. Having to pour a continuous foundation is painfully expensive (read more here: https://www.hansenpolebuildings.com/2011/10/buildings-why-not-stick-frame-construction/). Another issue with trying to stick frame a 16 foot high wall – the Building Codes will not allow it unless you have an engineer sealed design, further adding to the expense.

While “I” joists might be able to span the 24 feet successfully, it will probably be much more practical to do with prefabricated wood floor trusses (https://www.hansenpolebuildings.com/2014/09/floor-trusses/), as they can be designed to limit deflection (read about deflection here: https://www.hansenpolebuildings.com/2015/12/wood-floors-deflection-and-vibration/)  and afford the ability to run duct work and plumbing through the webbing. In order to get everything you want to fit in your new building, you are probably looking at an eave height of around 27 feet. You will want to be talking with your Planning Department to see if there will be height restrictions.

Post frame building columns are very strong in the compression (weight bearing) direction and getting columns 32 feet long is not a problem, as glue-laminated columns are easily available in this length. Footings can be easily designed to support all of the live and dead loads which will be imposed upon them by your new post frame building.

On your second floor, if you intend to go with a 40 psf (pounds per square foot) live load, you will be restricted to residential use. Office space requires 50 psf and light storage is 125 psf. Design the floor for what you will actually be using the space for and have no regrets later!