Tag Archives: fire separation

Frost Heave and Rodents, a Storage/House Combo, and Dead Attic Space

This week the Pole Barn Guru answers reader questions about prevention of frost heave and rodents getting in to a post frame garage, advice for a storage/house combo in Oregon, and how some buildings can have “dead attic space.”

DEAR POLE BARN GURU: I am concerned about frost heave and rodents getting into a post and frame garage. How high off the ground should the bottom girt be off the ground to prevent damage and frost heave and what is the best method to keep mice from getting in under the bottom girt. Should galvanized screen or maybe soffit metal be buried in the ground? Would pebble stone be a better choice along the building sides to minimize frost heave rather than gravel or clay soil? Your advice is appreciated, WALLY in KAKABEKA FALLS

DEAR WALLY: Bottom of your bottom girt (UC-4A pressure preservative treated splash plank) should be 3-1/2″ below top of your finished concrete slab on grade.

Here are a series of articles about what causes frost heave and how to avoid it:

Pole Building Structures: What Causes Frost Heaves?

Beat Frost the Easy Way…Post Construction Drainage

Preventing Frost Heaves in Pole Building Construction

Here is how to handle rodents: https://www.hansenpolebuildings.com/2021/03/rascally-rodents/


DEAR POLE BARN GURU: We are considering building a pole barn to store hay and equipment that also has an apartment area within. What would you suggest we build? We live in Central Oregon and we can get substantial snowfall as we butt up against the Cascade Mountain Range. We have horses and cows that we will be storing hay for, a tractor, two 4 wheelers, a couple of vehicles and two trailers. Thank you in advance for your assistance. JONI in BEND

DEAR JONI: One 4th of July we downhill snow skied Mount Bachelor’s summit before lunch, then hit The Deschutes River for white water rafting. We have provided hundreds of engineered post frame buildings to our clients in Oregon, so we know your area well.

Before getting into a snow load discussion, I would be remiss if I failed to share some pitfalls of adjoining living quarters to where animals are housed. Dust Rodents

Noise Odors

Fire separation – usually takes a two-hour firewall, meaning you have to go outside to go between uses. Cost of Insurance – fire potential is an issue Resale Value – appeals to a very small percentage of people, for reasons listed above. I would strongly encourage you to look at two individual structures. I will ask one of our Building Designers to reach out to you, to best assist you in design of your ideal building(s).


DEAR POLE BARN GURU: I work in commercial buildings a lot, that have similarities to pole barn design. Some are wood and steel, some are all steel framed. But none of them have spray foam, they’re either rockwool or fiberglass insulation. And ALL of their roofs are closed dead spaced with no venting at all. In lieu of your reply, how do they get away with this? Why can’t I emulate what they’re doing to some extent? Thanks again! DAVE in GALES CREEK

DEAR DAVE: These commercial buildings are utilizing what is loosely termed as “Metal Building Insulation”. This is typically a fiberglass batt, bonded to an air impermeable air barrier (blocks water and air). This facing must have an air permanence equal to or less than 0.02 L/s-m^2 at 75 Pa. pressure differential tested according to ASTM E 2178. All seams must be tightly sealed. This can be accomplished where roof purlins are typically every five feet and interior plane of underside of roof is not interrupted by members such as truss webs.





Fire Separation When Living With Large Animals

Fire Separation When Living With Large Animals

While barndominiums and shop houses have become quite a rage, for years we have been providing fully engineered post frame buildings combining animals (most often horses) with living spaces (usually as a full or partial second floor). Along with this come some perhaps unexpected design considerations.

Reader LISA in SNOHOMISH writes:

“I am finishing a loft apartment above a 6-stall barn in a pole building.  Snohomish County has indicated they want the ceiling of the barn and all posts and beams supporting the loft apartment to be covered in 5/8″ Type X Gypsum for fire protection.  

Gypsum on the ceiling is not a problem but, Gypsum on the posts is as horses will chew anything they can get their teeth on.  Is the requirement for Gypsum on posts and beams in this type of application normal?  Is there another way to fire proof these elements besides wrapping them with Gypsum, cement board, etc. Snohomish County does not seem too familiar with pole building construction and I am hoping there is some other kind of fire proofing (paint on or?) that would satisfy them.

Thank you.”

Mike the Pole Barn Guru responds:

Considering we have probably provided a hundred or so post frame (pole) buildings in Snohomish County, they actually do have more than a passing familiarity with them.

Hansen Buildings Horse BarnBecause you are combining dissimilar uses (large animals and a residence) you are required by Building Code (as well as your safety) to fire separate them. This is just one of many considerations when it comes to living adjacent to or above animals (others include high insurance costs, dust, noise, odors, insects, rodents and in your case having to go up and down stairs). For all of these listed reasons I always encourage those giving this combination consideration to ponder it carefully before moving forward, as well as to budget accordingly.

Most jurisdictions require one-hour (two layers of 5/8″ Type X gypsum wallboard) while I have even seen two-hours in some instances. In two-hour scenarios, any interior stairs must be fire protected from lower areas entirely and exit/entrances must be to the exterior, not to barn areas. 

Given what you have, your best bet will be to wrap members as the county requires, then cover anything within chewing range with galvanized steel or bare aluminum trims. These trims can be bent by either a steel roll former or a sheet metal shop in order to best fit with their field application and installed with screws through to underlying wood members.

Yes this is alot of work! But the main reason is safety, for both you and your horses. What’s that old adage which says, “an ounce of prevention is worth a pound of cure.”

Do’s and Don’ts of Attic Remodeling

If it is On the Internet, It Must be True

The internet is a great and wonderful place, a highway with a plethora of information rapidly available on nearly any subject. And for me, it has been my livelihood for the past dozen years.

On the ‘net can be found websites like Wikipedia (www.wikipedia.org), or as we refer to it in my household, “the sum of all knowledge”.

Sadly, for every bit of truly great information at one’s fingertips, is some really, really bad information.

One of my Facebook friends posted a link to an article, “What This Man Did to His Attic is Unbelievable. I Can’t Believe It Actually Worked”. https://home-design.diply.com/auntyacid/what-this-man-did-his-attic-is-unbelievable-i/64886/1

attic spaceNo wonder the writer can’t believe it actually worked is because it doesn’t!

Please, please, please…..never do attic remodeling like this to any pole (post frame) building! When it fails and people are injured or worse, I’d just as soon have had no involvement with it.

So, what is wrong with creating a livable space in an attic? After all, it is just wasted space otherwise.

Done right:

Step Number One would be to have contacted the Planning Department which has jurisdiction over the area where the building exists – to find out if Code will even allow such an attic remodeling space to be created. In most cases, the answer will be yes, however this is not the venue to go ahead first and ask for forgiveness later.

Step Number Two – we are talking about major structural changes here. A Registered Design Professional (RDP – engineer or architect) should be contracted with to design a structural solution which actually works….meaning it is safe for whoever uses the building!

There are so many problems with this particular “man cave”, where to begin in discussing them becomes almost daunting.

How about, “Never Cut A Truss!” I’ve written some about this in one of my Monday columns, “Ask the Pole Barn Guru”: https://www.hansenpolebuildings.com/blog/2014/08/truss-3/

Roof trusses which are designed to support the weight of a ceiling (gypsum wallboard and blown in insulation) could be designed for as little as five psf (pounds per square foot) of dead (permanent) load on the bottom chords. In most cases they are not designed to support ANY other loads.

Trusses can be designed for light weight storage loads, a 20 psf live load, but this would be an exception.

For habitable space within a truss, the minimum live load requirement is 30 psf – which makes it very possible the modified trusses in this article are being subjected to a load SIX TIMES what they were designed for, before they were cut!

Step Number Three – Fire Separation – If the attic remodeling or the access to this space pass through an area which was formerly garage, or are above the garage, adequate fire separation must be provided, which in most cases is going to be at least two layers of 5/8” Type X gypsum wallboard.

Step Number Four – In most jurisdictions, the steepest stairs within the limits of the Code will be a rise of 7-3/4 inches and a run of 10 inches, with a minimum width of three feet. At the top and bottom of the stairs, a landing must be provided which has a minimum dimension equal to the width of the stairs. (Learn more about stairs here: https://www.hansenpolebuildings.com/blog/2012/03/stairway/).

What has been created, by this building owner, is a structure which probably cannot be resold, as it has a non-Code conforming “room” which was constructed without a Building Permit!

Pole Barn House Part II

BarndominiumIf you didn’t read yesterday’s blog – it may be helpful to go back and read about my personal pole building house, inspired by my bride of 14 years.

And then, moving on to sharing from another pole barn house challenge:


We have a client in Colorado who has been trying to get a permit to build his combination garage and pole barn house since last fall. His building is similar to ours (a gambrel) with a smaller footprint of 2880 square feet. Upstairs will be a 1440 square foot living quarters. The downstairs is to be used strictly for the owner’s vehicles.

Should be easy, right?

I (as well as most of the post frame industry) have had little direct involvement with residential post frame. Here the Building Official is giving me a free lesson:

“….. forwarded me your email to help explain to you what is going on with the barn with dwelling above as noted below in your email.  The size/area of the overall structure kicks the entire structure into the 2012 IBC for review. As you know the R-3 fire area kicks the entire building into the sprinkler system requirements as noted in section 903.2.8 of the 2012 IBC. The character size/area and use of the barn/garage area within the structure lends itself to the S-2 classification except that it is private use and not commercial use. Thus locally we have determined to leave such areas classified as group U occupancies while having them meet the requirements of the S-2 occupancy. This being said, you need to look at foot note b of Table 508.4 in the 2012 IBC which states; The required separation from areas used only for private or pleasure vehicles shall be reduced by 1-hour but to not less than 1-hour.  

 Due to the possible mix of garage and barn type uses with these structures, the fuel loads in the unfortunate event of a fire can be extremely significant within the mixed barn/garage environment. Consider vehicles of varying types with fuel in their tanks, storage cans of fuel, paints, solvents of varying types, hay, straw, wood shavings or chips, etc.,. We would be well within the scope of the intent of the code to jump to an even higher hazard occupancy classification which would lead to not only a different type of sprinkler system but also maintaining a 2 to 3-hour separation between the occupancies within the structure. Locally we have decided to take the approach noted above in the first paragraph and allow the owners of such structures two options.

Option 1 is to divide up the occupancy areas within the structure with a 2-hour Fire Wall (as described in section 706) such that in the eyes of the code, we have two separate structures. The dwelling area may then be constructed under the IRC instead of the IBC. If the barn or garage area with the dwelling area removed is still over 3,000 square feet it would still fall under the IBC for review and meet the requirements needed for that review. If the garage/barn area left over from subtracting out the dwelling area is less than 3,000 square feet, it too may be constructed under the 2012 IRC as an accessory structure. Again, once the true 2-hour Fire Wall exists the code will allow us to look at each one as a separate structure. The key here is it must be a true Fire Wall type separation and not a Fire Barrier. Considering horizontal fire wall assemblies, there is some justification to make them 3-hour instead of 2-hour so that they serve their intended purpose in the best of ways. We have not gone to the 3-hour on horizontal fire wall assemblies at this point.

 Option 2 is to fully sprinkle the structure and provide the “not less than 1-hour” fire separation between the occupancies concerned (see leading paragraph notes). The local Fire Department having jurisdiction would need to review the structure being sprinkled to decide which type of sprinkler system is needed for proper structure protection.“

Due to the versatility of post frame buildings, we will see some very complex structures, with an entirely new challenges to be faced. A pole barn house is extremely efficient, functional, not to mention affordable at a lesser cost than stick built. It is a brave new world we are entering!