Designing

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 I designed and built my own hangar home, I placed an actual motor home door in the front of the hangar. It is 12 feet high..  At that time I considered that it was sufficiently appropriate for any motor home that I would realistically obtain. I still do. However, that was 10 years ago and since then I have learned that many motor homes are being built  with heights that exceed 12 feet. However even the large ones do not necessarily exceed 12’. I have a son with a 36 foot motor home and we measured it the other day and found it would easily fit, even with the AC, through the door. His has a “basement” (storage under the floor) and other luxury factors yet fits with no issues. However, the length is tight. A typical 2000 sqft hangar (50’x40’ is a typical footprint) leaves only about 38’8” inside dimension to fit the unit. Workable…..but tight, by many standards. When one thinks of it, if a Residential Aircraft Hangar is being comtemplate (2000 sqft limit) then any motor home that will reasonably fit will be unlikely to exceed 12 feet in height.  Frankly I believe that my 12 foot height is quite appropriate. However, the limitations on motor homes heights, by law at of the time of this writing, is 13 feet and 6 inches. Realistically, as in airplanes as noted above, extremely large motor homes such as the Provost style coaches (sizes 40’ or longer) can exceed 13’. However even the largest of these, at the time of this writing, rarely reach 13’. And the same argument would apply, if one is looking at a Residential Aircraft Hangar limited to 2000 ft.² then likely 40 feet will be too bit and a unit much larger than 32 to 34 feet in length will be impractical. So a good rule of thumb, in my opinion,, is that for residential hangers a 13 foot height  is more than sufficient  for anything that one might reasonably be storing. As with airplanes, the larger hangers may require beg for greater heights of ceiling and doors however I think that 14 feet  would be a comfortable height for hangers all the way up to 4000 ft.². Above that, owners may be considering much larger airplanes and the airplane, note 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. This, however, is dependent upon the type of hangar door chosen and these factors must be considered during design.

SUMMARY

So in my opinion, if one is looking to build in Residential Aircraft Hangar of typical size of 50 feet wide by 40 feet deep, and excellent 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 material used) and to make the door 13 feet high.  This will accommodate most any aircraft that can reasonably be fit within the space and same for the motor homes. There are, of course, 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.

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.