I need some help with Barndominium steel structure?


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Hello fellow architects I have a new client that wants to build a Barndominium essentially a house inside of a metal building. I am familiar with the concept but I have never designed one. My questions are where would you start as far as the metal building is concerned. I would imagine that its much like the truss company they provide the plans and I just have an approximate idea until I see them. I'm wondering if any of you have some input would a metal building mf provide me some basics as far as size of straight columns and beams. and approx. placement. Also my client was wanting a 4" concrete pad and 5 or 6 for the garage I think he is hoping to save some money. I told him the concrete will have to be engineered for the structure but that probably all of it will have to be 5" thick. The building is 104' long and 38' wide including porches with a 5:12 roof slope. My other question is how tall to the eves should the side wall be if my interior celling height is 9'. I do have the beams catalogue downloaded from chief. Any input would so much appreciated Thanks Landry

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1.  You can't call yourself an Architect unless you are licensed as such.

2.  If you don't fully understand the structure you are proposing then you should seek the services of a Structural Engineer.

 

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1 hour ago, lms_jam said:

The building is 104" long and 38" wide including porches

That's a very small building!

 

1 hour ago, lms_jam said:

with a 12:4 roof slope.

And a very steep roof!

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10 minutes ago, glennw said:

That's a very small building!

 

And a very steep roof!

Sorry meant 104' and 38' with a 5:12 roof I live in snow country

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Although I am not an Architect I did graduate from an Architecture school and was taught structural design by one of the preeminent experts in the field at the time (he designed the St. Louis Arch structural plans). I will impart all the knowledge that he passed on to my class. "Deeper, Cheaper, Better". I hope this helps.

Pratt '89

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If it is a pole barn structure, the building will be supported by columns which will have their own pier support, the interior concrete slab is structurally independent of the building load so barring any high point loads on the slab from machinery or interior structure ( ie: car lifts, mezzanine columns etc.) a 4" slab would be sufficient although it would have to haunched at the exterior walls and possibly at interior wall locations as well if first floor ceiling will be a load bearing surface (2nd floor, storage attic etc.)

 

However there are multiple variations of metal buildings so there is a lot of unanswered questions here. Not to mention your use of the term Barndominium seems like a play on condominium which would entail a multi-family residence and specific requirements for fire separation between units among other things. Be aware that fire-stopping becomes a very intricate issue in the situation you describe.

 

The eave height is dependent on the desired interior height, the length of the overhang and the slope of the roof which all work together to determine the final T.O.P. height.

 

 

 

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A residential floor load on a bearing wall needs a footing with continuous rebar.  A 4" slab is NOT going to work for this purpose.

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It was my understanding that it was to be a metal building in which case the exterior "skin" hangs from girts supported by the columns which have their own pier foundation, in that case there is no exterior load bearing "wall" as all the load transfers to the columns. Considering a minimum compressive strength of 2500 lbs/sqft a 4" concrete floor laid on a properly prepared compacted gravel base would far exceed the code minimums for floors which is less than 100 lbs/sqft in a worst case scenario. However increasing the slab thickness with an integral footer or "haunch" at interior walls, especially if they will be more than one story in height, would be recommended. And because the perimeter walls would not be carrying any roof load they would technically be interior walls as well. The 5" slab at garage locations would only be recommended for cases where commercial grade trucks, equipment or large RV's would be parked in the space. When I have built fire halls the pumper trucks weigh a ridiculous amount with full water tanks and we only use 6" slabs in those cases.

 

Please in the future fully read and comprehend the issues before downgrading someones posts. 

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Hello I'm sorry I've been sick the past week. Thanks for the responses I am working on a budget and I guess at the moment I'm just looking for exterior wall thickness. I thought maybe there was a standard size for x size building. The structure will be straight column and will sit on a concrete slab foundation with piers. I know that the structure and foundation will have to engineered taking into consideration the soil etc. My client doesn't have a building site or a MF for the metal building yet. He just wants something that he can show the city building inspector and the metal building MF and some other people so he can start getting a cost idea. Not the way I would go about things but to each his own.

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8 hours ago, BiggPopppaChief said:

If it is a pole barn structure, the building will be supported by columns which will have their own pier support, the interior concrete slab is structurally independent of the building load so barring any high point loads on the slab from machinery or interior structure ( ie: car lifts, mezzanine columns etc.) a 4" slab would be sufficient although it would have to haunched at the exterior walls and possibly at interior wall locations as well if first floor ceiling will be a load bearing surface (2nd floor, storage attic etc.)

 

However there are multiple variations of metal buildings so there is a lot of unanswered questions here. Not to mention your use of the term Barndominium seems like a play on condominium which would entail a multi-family residence and specific requirements for fire separation between units among other things. Be aware that fire-stopping becomes a very intricate issue in the situation you describe.

 

The eave height is dependent on the desired interior height, the length of the overhang and the slope of the roof which all work together to determine the final T.O.P. height.

 

 

 

Yes it will be two residences separated by the garage.

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A slab supporting a wall is not entirely about the compressive strength.  It is about the lack of a footing.  A slab on grade could become subject to frost heave.  The OP is from Eagar AZ.  The elevation is 7000' so it might be an issue for the project.  I would hate to be trying to defend the choice of eliminating footings at some point in the future but then again, anyone that wants to live in a pole barn probably doesn't really care.

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Here is one I did recently in Northern California. (No Snow Load)

The steel building manufacturer said you can have X amount of windows, doors and skylights. As long as they do not interfere with any of our support beams you can place them where ever you want. 

I took the plan they provided and created a chief model with the steel framing in place. Then I added a 2x6 interior wall just inside the steel structure for the living area (do this by adding a 2x6 interior wall with a 2" air gap to the exterior wall). I do not recommend trying to wedge in 2x framing between the horizontal steel girts at 16" o.c. Not only is it a pain and labor intensive but having a traditionally framed wall allows for the elect, plumb, mech. to go smother, it also creates a barrier between the steel siding and the insulation. That is always a traditioned condensing point. You lose some square feet but that is a huge building.

Basically find a steel building contractor that is a factory rep. They will give you plans to start from. Then go from there.

Good luck. 

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