Hangar Homes

Code Change Needed to Address Residential Hangar Home Limitations

by Engineer Designer on January 11, 2017

As a specialist in hangar home design and engineering for the last 10 years, I have seen that many of my clients desire hangar sizes to exceed 2000 ft.². This is reasonable given the way so many intend to use this residential space: multiple airplanes, tractors, motorhomes, antique cars and many other private and residential uses.

However, per the current code, once the hangar size exceeds 2000 ft.² the requirements become rather onerous and sometimes nearly prohibitive to achieving their desired aims. In this article I will address the myriad of requirements that the larger space requires, (these being addressed in other articles) but I want to proposa a simple solution would solve the entire situation.

Current codes define residential hangars as not having floor areas that exceed 2000 ft.² and heights (defined as “building height”) that exceed 20 feet. The “Building Height” is defined as being measured from the average height of the highest roof plane over the hangar to the grade. It is not measured from the ceiling of the hangar to the ground. These two requirements create a multitude of “problems” for private use residential hangar owners and, in my opinion (and others) these could be easily addressed. Here is a discussion of several points, and a suggested remedy in the Code:

Many folk who want to build residential aircraft hangars, as part or near their homes, with spaces than 2000 sqft. These are still “Residential Hangars” used in residential setting. Often they store more than one airplane, or keep a light workshop in the space, or store other normal household items, or park RV’s (which are not allowed outside), or antique cars, or garden equipment or small tractors and even the family car. Increasing the 2000 sqft limit would allow these completely reasonable uses to occur.
The current definition, being related to “Building Height” as been known to prevent folks from legally placing a home over a hangar because the the roof over the second living area establishes the “Building Height” which absolutely makes the living unit above unacceptabily low and restrictive. This can be easily addressed by limiting the hangar height based on the ceiling height of the hangar rather than the “Building Height”.
Residential Hangars are usually built in areas limited by residential zoning codes and can not legally exceed standard residential usage. More dangerous uses (ie. Commercial) are prohibited in residential settings, therefore, elevated hazards associated with commercial use become a mute point.
Stored Airplanes are more safe to store than are Recreational Vehicles (with propane tank). RV’s typically hold more fuel than General Aviation aircraft. Yet there are no restrictions in the Code for parking an RV in a large garage.
Stored Airplanes are more safe than farm equipment which are typically dirty and greasy. Farm equipment, lawn mowers, etc, can be stored, currently, in a garage without restriction.
Stored Airplanes have gas tanks that hold fuels with equal hazardous potentials of automobiles, recreational vehicles or farm and garden equipments. To assume greater hazard is arbitrary.
Typical Residential Aircraft hangars are usually cleaner than are barns and garages, thus reducing fire hazards.
Airplanes have a Master Switch that turns off all electrical supply to the airplane thus isolating any sparking issues.
Airplanes, by law, are carefully inspected yearly to assure no mechancial issues including leaks, shorts or other issues that might cause a fire.
Airplanes typically have fuel shut off valves.
Airplanes are typically kept cleaner than any other type of vehicles (because they are often more expensive).
Airplanes, when not flying, are docile and sluggish vehicles that are relatively light and very safe.
There are no provisions in the Code that limit the sizes of a car garage or ancilliary barn. And there is no limitation on how they are used (subject to local zoning restrictions). Aircraft storage (for residential settings) should be no more stringent.
In general, Aircraft are more costly, cared for, and better documented than any other piece of equipment on earth.
There are 593,000 pilots, and at least 250,000 Aircraft stored in Hangars of all types, so these Codes have impact.

It is my opinion that the existing codes that affect Residential Hangars were written by non-pilots who, uninformed, tended to take the attitude that “airplanes are dangerous”. Most pilots run in to this consideration, routinely. It would be understandable and expected that these attitudes regarding safety “in the air” would translate to more stringent requirements for them as they are being stored. But, again, airplanes are slow and docile creatures, well maintained and quite safe when stored. Storing and flying airplanes are two entirely different activities and risk levels.

There is no need to change the complicated concepts that are written into the Building and Fire Codes. Most of these are well considered and should be left alone. We simply need a change in the definition of a Residential Aircraft Hangar. It is my opinion that this would handle the concerns of countless hangar home owners and still meet the safety concerns that all of us share. I am suggesting that the following changes be made to the definition of a Residential Aircraft Hangar (marked out as deleted and red as additions to the language: "RESIDENTIAL AIRCRAFT HANGAR. An accessory building less than 2,000 square feet (186 m2) 5,000 square feet (465m2) and a ceiling height not to exceed 18 feet as measured above the lowest hangar finish floor 20 feet (6096 mm) in building height constructed on a one- or two family property where aircraft are stored. Such use will be considered as a residential accessory use incidental to the dwelling." The argument for fixing the height restruction to ceiling height rather than building height is that it will not restrict the height of anything built above the hangar (such as a home). Local zoning would usually limit any “building height” restrictions which should suffice.

This recommendation has been forwarded to ICCSAFE.ORG.

Please feel free to comment by writing me at PE@EngineerDesigner.Com. If you wish to chime in or get involved with your support for this issue, let me know.

Ken Risley

Residential Aircraft Hangar Door and Ceiling Heights – Here are a few points to consider.

by Engineer Designer on July 5, 2016

When deciding upon the specifications of a residential hangar home one of the decisions we face is how high to make the ceilings and main doors of the hangar. Besides factors of cost, there are a few specific issues that should be addressed as one endeavors to make that decision. These factors have to do with the Building Codes themselves as well as the size of the equipment that we intend to park within the confines of the hangar.. As most of us have discovered in our lives, we tend to fill every available nook and cranny of our existence with our “stuff”. George Carlin had a great bit regarding the subject which is hilarious to hear as it hits very close to the truth in most of our lives. A hangar is no exception. Of course we keep our airplane(s) in the hangar but usually that space becomes home to much, much more. One key possession that more and more folks are storing in their hangers is their motor home RV’s . So a common question, when designing a hangar home, whether or not the owner owns a motor home or not (because he should consider future owners), is how large and how high do we build the hangar to accommodate not only our airplane(s) also our RV’s. Here are some factors to consider:

THE RULES (ie, the Codes)

When I speak of the rules I am talking about the Building Code. Speaking specifically of “residential aircraft hangars” there are height limitations which are voiced in the code which can become factors when determining the ceiling height of the structure. The building code does not address, directly, the height of the ceiling but it does address the overall building height as measured by the average height of its highest roof plane. This can certainly relate to ceiling heights. This factor becomes more complicated if one is looking to build a residential home above the hangar and this factor, occasionally, can affect the entire project.. As a side, future articles will address this interesting conundrum in the industry with specific recommendations as to how to handle. But for our purposes here, generally, ceiling height and the code limitations, as currently written, are such that most reasonable heights, within a one story structure, will comply with the Code.

AIRCRAFT TAIL HEIGHTS

Let’s face it, the main reason for a hangar home is to store our precious airplanes. Most general aviation aircraft have tail heights significantly less than 14 feet. Unless one is parking his or her Airbus or some type of airliner or large twin in the hangar, he or she can be quite certain that most airplanes will fit into hangers with clearances as low as 12 feet. Most Beechcraft airplanes will fit through a door opening with a 14 foot high clearance with the exceptions of all the King Air’s and Queen Air’s. Even the Beechcraft Baren and the twin Bonanzas will fit through a 12 foot high opening.. Most of the Cessna’s will fit with the exceptions of the Caravans and the Citations. Bottom line, if you are flying a jet or large twin of most any manufacturer then you will likely be wanting a hangar much larger than the 2000 ft.² limitation for residential hangar and you will want a door and ceiling height of appropriate heights. If you are operating in that range of aircraft you undoubtedly know the height of your aircraft and will give your designer appropriate instructions to accommodate the sizes. However, for most GA aircrafts, the 12 to 13 foot height is quite appropriate and will fit most anything that we see in the typical aviation communities.

MOTORHOME HEIGHTS

Motor homes come in a wide range of heights. When deciding on the specifications of a residential hangar home, one of the decisions is how high to make the ceilings and main doors of the hangar. This includes consideration of the height of motor homes that may be stored in the hangar. When designing and building a hangar home, it's essential to consider the size and height of the equipment that will be parked within the hangar. When the I designed and built my own hangar home, 18 years ago, I placed an actual motor home door in the front of the hangar. The door is 12 feet high, which I considered sufficiently appropriate for any motor home that I'd realistically obtain. However, since then, many motor homes are being built with heights that exceed 12 feet, although even the large ones do not necessarily exceed 12 feet. For example, the my son has a 36-foot motor home, which easily fits through the 12-foot high door with no issues, despite having a “basement” and other luxury features. However, the length is tight, and a typical 2000 sqft hangar (50’x40’ is a typical footprint) leaves only about 38’8” inside dimension to fit the unit. This may be workable but tight by many standards. The limitations on motor homes heights, by law at the time of this writing, is 13 feet and 6 inches. Extremely large motor homes such as the Provost style coaches (sizes 40’ or longer) can exceed 13 feet. However, even the largest of these, at the time of this writing, rarely reach 13 feet. If a Residential Aircraft Hangar is being contemplated (2000 sqft limit), then any motor home that would reasonably fit will be unlikely to exceed 12 feet in height. Frankly, I think that my 12-foot height is quite appropriate for a smaller hangar my size hangar. About 2 years ago my wife and I did purchase a 28 foot Class C motorhome (a perfect size for us). We store it in the hangar, of course, and park a Smart Car behind and parallel to it. Plenty of room. However, a good rule of thumb for residential hangars is that a 13-foot height is more than sufficient for anything that one might reasonably be storing. As with airplanes, the larger hangars may require greater heights of ceiling and doors. However 14 feet would be a comfortable height for hangars all the way up to 4000 ft.². Above that, owners may be considering much larger airplanes, and the airplane, not the motor home, will become the basis for the design of all height clearances.

HEADERS ABOVE HANGAR DOORS

Obviously, ceiling height and hangar door opening heights might be different. If the structural span over the hangar door is designed correctly, one can eliminate the need for a header extending down below the ceiling and can actually make the door height and ceiling heights very close together indeed. However, this is dependent upon the type of hangar door chosen, and these factors must be considered during the design process.

SUMMARY

When building a Residential Aircraft Hangar of typical size of 50 feet wide by 40 feet deep, a good target for height is for the ceilings to be placed at 13’4” above the hangar floor (this is a perfect height for masonry walls and can be easily achieved regardless of the material used), and to make the door 13 feet high. Larger hangars should have ceiling and door heights of at least 14 feet. This will accommodate most any aircraft that can reasonably be fit within the space, as well as most motor homes. Of course, there are always exceptions, but this should serve as a good rule of thumb. As always, you can contact me any time with questions.

Living Area over Hangar Arrangements

by Engineer Designer on April 27, 2016

The Appeal I am seeing more and more requests for hangar home combinations where the living area is built above the hangar. Around the Internet there are a few pictures of projects, some which have not yet been built, which show nice and neat depictions of this type of an arrangement. Its appeal, on certain levels, is easy to understand. Such an arrangement can be tidy and well contained and not be as sprawling as other types of projects with hangars on the same level as living area, or even separate.

There can be some advantages to having the living area over the hangar.

This type of an arrangement can lend to very nice opportunities to view the runway from the comfort of one’s home. With the living room, or family room or other common areas of living space set over the hangar these can be designed to face the runway giving the occupants a wonderful theater from which to watch their fellow pilots land airplanes. This can be quite enjoyable as any pilot knows who has sat in a chair applauding, and perhaps judging, landings of his compatriots.

This arrangement can be advantageous for narrow lots where separate hangar and living structures might force the living area to be built away from the runway with the hangar between. While this may be something desired in some cases, I find that many folks, if on the runway, request some sort of runway view. If the lot is small this can be difficult to achieve by any other means.

Going “up” with a design has some inherent efficiencies in that the same roof covers both living area and hangar and the same slab, or lower floor, functions for both areas. There is an ongoing debate in the industry as to which is cheaper to build, a one or a two story home. In my own evaluation I have found two to be comparable when all elements are taken into consideration. But nonetheless there is an inherent efficiency to having the home rest over the hangar area.

The Challenges and Solutions However there are several disadvantages and challenges for this type of arrangement and this could be the reason why there are not more of these types of structures to be found.

The key problem with having the hangar under the living area is that, given the typical sizes of hangars, usually at least 2000 ft.² with a typical width of 50 feet, it is difficult to span that distance with any structural element that can withstand the deflection forces of the live loads. Though structural elements can be designed to hold the weight the problem falls in the area of deflection which can manifest in what is called, in the industry, “bounce”. Bounce is basically the vibration which can be detected by human occupants as a result of shifts in position of various users of the space. One can be sitting in the living room and have a group of children running across the living room and actually feel the vibration of their movement in the floor and furniture. This can be unsettling. Though not an actual structural problem it is more a problem of perception. It is, by its nature, somewhat subjective but studies have been made on the subject and bounce is a real potential problem.

The only solution to the bouncing problem is to have the structural member designed with enough stiffness to resist deflection. Stiffness is largely achieved by a structural element's depth. If one is using a beam of even 2 feet of depth across the 50 foot span this would generally not be sufficient to handle the “bounce” to the extent most people would find desirable.

Of course, these factors can be controlled by limiting the size of the hangar but generally most folks want to have at least 2000 ft.² of hangar space and a typical size for this is 50’ x 40’. The 50 foot side is usually the side for the hangar door. Running the beam from front to back would have its own inherent problems of causing a substantial point load in the middle of the hangar door header system.

So limiting the size of the hangar can certainly mitigate some of the bouncing problem. It is a matter of whether or not the owner is willing to live with a smaller hangar.

I have had owners quite satisfied with smaller hangars.

Another solution is to add a post to the beam. This makes all the differences by, effectively, cutting the beam length in half (if placed in the center). One of my clients, in North Carolina,, is parking a relatively small home-built airplane in his hangar and is able to tolerate a post set in the middle of the long beam. He is able to easily park his aircraft in the space despite the post.

Another strategy is to use a “T” hangar where the tail, or even the nose, rests in a more narrow portion of the hangar. This design segregates the rear left and right corners of the hangar into either living areas or some type of shop or storage space. It opens up the opportunity to create load-bearing members in strategic locations to reduce the length of the main supporting element for the home upstairs.

Another, less common, strategy is to create a “wall truss”. This can be a major wall contained within the living area upstairs which is designed as a deep truss to support secondary floor and roof structures. Passageways through the truss can be challenging and that is part of the job of the designing engineer to solve.

Three Other Challenges. The living area over hangar concept can be “boxy”. There are ways around this but the basic massing of this type of structure is a challenge that needs to be handled in most cases.

Secondly, this type of arrangement puts most of the living area on the second level requiring either stairs or an elevator for egress. If the owners are entering the senior status of life this can be a factor and an elevator is can be the best solution.

And, finally, if the hangar exceeds 2000 sqft in size, substantial fire separation requirements can kick in. These require special structures in the ceiling of the hangar to separate the hangar and living spaces. This is quite technical, and can usually be solved.

A Trend that begs for Solutions It appears there may be a trend pointing to an increased popularity of the home over hangar arrangement. I think it behooves designers and engineers to begin solving this set of interesting challenges. Homes over hangars can be quite charming and even include decking placed in front of the home, over the hangar, providing a great area for relaxing and watching the aviation experience.

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