Code Change Needed to Address Residential Hangar Home Limitations

by Engineer Designer on January 11, 2017

hemfil twoAs 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

Home Over Hangar

by KenRisley on August 4, 2014

house over hangar As a hangar home designer, I  occasionally get requests for a hangar home to be built on top of the hangar. Interestingly enough, I've not seen many of these actually built. In my own neighborhood of over 50 hangar homes we do not have a single instance of a hangar with a home on top. But throughout the Internet there are many pictures of such projects. I don't know the actual percentage of hangar homes that are built which use this format but I suspect that is a relatively low number. This may be changing.

Here is one example of a home that I see popping up on the internet. As I understand it, it has not yet been built. But it is an appealing look. You might notice that the hangar does not appear to be very wide - and this is a duplex. home over hangar

Placing a home over the hangar can be an excellent idea if faced with a tight (ie. small) building site. If properly designed, these types of structures can be efficiently build utilizing a relatively small ground floor area for relatively large usage space.

But on the negative side, these types of projects can look boxy. There are remedies (see below) but the nature of these structures tend to lend to a heavy "over/under" look. They also tend to force the hangars to be relatively small due to structural challenges which I will describe below. They can also quickly push the height restrictions since hangars need to be relatively tall and with the addition of a home on top can push some zoning limits. Another disadvantage is that the cars and the living area are on separate levels forcing one to use either stairs or an elevator to get up to the living space. Even two-story homes associated with hangars have a lower living level which will contain the kitchen and common living areas which is quite convenient for bringing in the groceries, accepting guests etc. It can be awkward having guests climb stairs to find the front door. If one is looking for a two-story home it is essentially impossible to do over a hangar because it will bring a height of much higher than many local zoning requirements will allow. Plus it will look very much out of balance.

The main structural challenge with a home built over hangar is that since we do not want any types of structural posts inside the hangar the hangar must be spanned by a beam of sufficient size to handle the loads. This tends to restrict the size of the hangars, either in width or depth. A reduced depth can allow us to bear the structure of the upper home on both the front and back walls and not create problematic floor joist spans. A reduced width will allow direct use of shorter structural members, again, reducing the span problem.

While beans can be easily designed to carry the required loads, the  problem is, what we call in engineering, "deflection". Deflection is the tendency of a beam to drupe or bend downward as a result of the weight that it is bearing. This, in itself, is not a problem and can be controlled but it can lend to a phenomenon called "bounce". If the beam is not "stiff" enough it can cause the floor above to vibrate and bounce as a result of any type of standard human traffic. I've been in structures where this had not been properly accommodated, and could feel the floor moving and bouncing with just a few children running from one end of the structure to the other. The beams were "strong" enough to be safe but not "stiff" enough to prevent the bounce.

"Stiffness" is a function of many factors but the beam depth is a big one. The key solution to reduce bounce is to design the beam to maximize its depth. Its depth has to be significant compared to its length. The longer the beam, the deeper it must be.

There are ways to do this. A beam can directly be chosen due to its substantial depth but this can be an architectural challenge in that it might protrude quite a bit into valuable spaces. Another way is to "skin" a strategic wall in the home above and letting it act as a deep beam unto itself. This can be cleverly designed and can certainly handle the situation. In these types of beams, depth is more important than weight.

If one is looking to have as living quarters above the hangar, the easiest solution is to build a smaller hangar, either in depth or width. If an owner is happy with the hangar size such as this, it can be an excellent way to proceed.

To handle the boxy look one can add facade features as well as design outcroppings to add interest.

In my experience, the majority of hangar home owners like to have their homes look like a typical residence and to de-emphasize the overwhelming effects of the hangar. With good architectural design this is relatively easy to achieve. It is easiest to achieve when the home and hangar are spread over a larger site which allows the architectural elements of the hangar and the home to gracefully blend. Personally, this is my favorite way to attack such a project.

If you are looking to build a hangar home, certainly do not hesitate to consider every option available. An experienced hangar home designer can surely help. Whether you choose a side-by-side hangar home structure, or choose to place the home over the hangar, an excellent solution can always be found.

See Additional Articles on this subject. Home over Hangar Arrangements.

When Considering A Hangar Home Design These Points Should Be Kept In Mind

by Engineer Designer on November 18, 2012

Hangar HomeFor pilots, living with your airplane and living in a hangar home is a dream that they may have had for many years. Most never do it, but those who do are in for a lifestyle like no other they have experienced. Hangar homes are unique. If you're looking to design and build one, here is a checklist of some of the items that you will want to keep in mind prior to and during the design.

1.Most aviation communities have architectural covenants. It is important to know these rules. Many are unique to these types of communities such as issues regarding street sign heights, taxiway clearance and the like. Most covenants include requirements for sizes of the homes and even the hangars themselves. Some communities dictate whether the hangar can face the runway directly or not. Some address issues such as whether or not the hangar must blend in with the home. These are all factors that need to be considered before one begins the adventure of designing and building a hangar home.

2.Hangar home sites vary in size. You'll find very large sites where placement is not much of an issue, and you'll find smaller ones where you need to know the setbacks. Slope of the site is also an important factor. Generally on sloped sites, it is best to place the hangar on the low side and the home on the high side of the site. This can add harmony and balance to the combination of the hangar and the home.

3.Hangar size is also something to consider. There is an important distinction between hangars that are up to 2000 square feet and those that are larger. In most codes which govern hangar homes in the United States hangars up to and including 2000 square feet can be built with less restricting standards than larger hangars. Larger hangars usually require more commercial-like code standards. When deciding on the size of your hangar you should keep that in mind. However the function of the hangar is, of course, tantamount. If you intend to have several aircraft then having a size greater than 2000 ft. might be required. See below for other uses of hangars which can affect the required size.

4.You'll have to make a decision whether or not to connect the hangar to the home or to build it separately from the home. There are several considerations. Hangars that are connected to the home tend to be slightly cheaper to build, and are considered quite desirable by many pilots. An advantage, of course, is to be able to avoid the weather and walk straight from the house into the hangar to see your airplane. If you intend, however, to build projects in your hangar then separating it from the house may be the most desirable. Building projects often create sounds and smells which are best separated from the house. There are also architectural factors that come into play when connecting a hangar in a home and these, too, should be considered. Hiring an experienced hangar home designer will make this easy.

5.Hangers are not only for airplanes. While almost all hangers eventually become storage bins of some sort, many are used quite intentionally for functions such as workshops, storing their boats, storing race cars and, quite, commonly, to store motorhomes. Motorhomes and airplane sizes are usually the determining factor as to how high to make the ceiling of the hangar. Motorhomes, especially the modern ones, are usually taller than 13 feet in height. So when considering the design of your hangar keep in mind any uses you intend to put it to beyond that of storing your precious airplane.

6.Another important decision is to determine what type of the door you want. Hangar doors come, basically, in three types: hydraulic, accordion and bifold. There may be others but those are the most common. Hydraulic doors are usually hinged at the top and are opened as one single slab and in the open positions act as separate roof shielding the area just outside the hangar. These tend to be expensive but are very popular. Another common door is the bifold door. Bifold hangar doors normally have horizontal hinges, usually only one horizontally in the center. They are raised with belts or chains and tend to raise from the bottom up. Accordion doors are less common but are extremely practical. They require a track both at the top and the bottom and can be simply pushed to the side to open up the space. One advantage to accordion doors is that they do not require electricity to operate. Looking at various doors types is a good idea so that you can make an educated choice as to what type of door to select.

7.What kind of a beam one is going to have over the hangar door is an important factor. Hangar doors are, typically, well over 40 feet wide and often as wide as 50 to 55 feet. Spanning that distance over the top of the door can become a structural problem. One way to solve it is to place a steel I-beam over the door and let the I-beam support the weight of the roof over the hangar. This can be cumbersome in the fact that the beam will have to generally extend down into the space of the hangar thereby requiring the ceiling of the hangar to be significantly higher than the top of the door. An excellent way to handle this, is to use a gable or a modified gable crossing over the opening. With a properly designed roof a gable truss, generally several plys, can be placed over the hangar door and act as a beam and a major advantage of this is that the bottom of this beam does not protrude below the ceiling level of the hangar. In this instance the hangar door can be pressed more closely to the ceiling and give one greater clearance for motorhomes or airplanes.

8.Another thing to consider is fuel. Do you want to keep fuel in a fuel tank that you will keep inside your hangar? Perhaps there is fuel on the property that is maintained by the Association; this can be an excellent way when available. Of course, one can always fly out for fuel and this is workable most of the time but it does require careful organization of one's flights and fuel stops.

These are only a few points to consider in the design of your hangar home - there are many others. Due to the uniqueness of hangar homes design it is recommended that you choose a designer who has had ample experience in designing hangar homes and who preferably lives and a hangar home personally. If you're looking for designs on the Internet, you will likely become frustrated. If you're intending to invest in a hangar homes to be built, it is best to find a designer to custom design a plan uniquely for you. Regardless of what type of design you end up building, your decision to design and build a hangar home will be, without doubt, one of the most thrilling and fulfilling actions you will take a pilot.

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