A couple things come to mind, Joe, as I read your comments.
I remember my own considerations when I built my hangar, which is 50 X 50 X 16 (eaves) with a 44' X 14' door.
Firstly,....I'd never do another weld-up design. I could have finished the job much faster with a bolt-together because at the time I didn't know diddely about welding....which meant I didn't save any money because I had to hire out all my welding. It also means I have no engineering guarantees (for whatever that's worth. I've already witnessed 75 mph gusts and horizontal 1" hail with no damage. But if ever you consider taking in a renter, hangar-keepers insurance may be involved, and local bldg. codes may be also.) A bolt-together actually would have come out about the same money all considering. Plan on about $5K for erection. (So what else did you expect? You ever have one that
didn't potentially cost a bunch?)
Next,.... the vast majority of metal bldg designs have the girts (those C or Z-purlins which go around the circumference of the walls) outside the uprights. This steals about a whole foot of floorspace all the way around your bldg. My hangar is my own design, which although pretty conventional, has a couple of important-to-me features such as my girts being with-IN the uprights. This gave me that 1-foot of floorspace back, and allowed a wider door and more floorspace on the same footprint slab.
Also, when you do your slab, make certain you specify the quality of concrete. I"d recommend "6-sack" strength. Houses are commonly "4-sack" and is sometimes used by contractors when they know they're dealing with an unknowlegeable buyer or think they're building for a lightweight vehicle/aircraft. Additional cement in the mix is not that much more expensive, considering that the majority of cost is the basic mix, re-bar, site prep, and labor. Put a central drain in your slab. Have them slope from outer edge towards the center at least 1" slope, and then within a 2 foot circle around the drain, have it slope additionally another inch....like a birdbath. Lead the under-slab drain away from the bldg, downhill, and/or into a sand-filled evaporation pallet. If ever you have a hazardous liquid leak,...it'll get it out of the hangar fast and avoid EPA lawyers (which I know you like to hang out with, but .... you really need to quit spending so much of your time with attorneys and spread your social calendar among others types.)
Next, .... When planning your slab...don't forget the ramp leading into the main door....and don't forget an additional personel door somewhere near the rear of the hangar....and the steps leading up to that door. It's cheaper to include those items while the slab is being poured than call them back out later on. Also, don't forget to include an outside perimeter metal sheeting ledge in your slab. Tres-Hermano's concrete company may not be familiar with this important, but simple feature of a metal bldg. slab.
Also think about whether or not you want sub-floor electrical, plumbing, toilet, etc. before you contract for a slab.
Next, .... Think about insulating your inside walls of the metal bldg. I don't think the chicken-wire method is necessary. Modern materials have reinforcing in their vapor barrier fabric. Avoid "blown" insulation, unless your local fire code requires it on the structural steel. Why insulate? Because it'll really cut down on the radiant heat problem on sunny days, and it'll also cut down on heating/cooling costs of the home you intend to include within the bldg. (if any.) It also makes a cold day, much better inside the bldg, even without addt'l heat.
Next,....Consider what type of main door you want. Bi-fold? Hydraulic swing-out? Sliders? Unless you really want a powered door, or unless you have real-estate/lot-size constraints...I'd recommend simple sliding doors if you intend to install them yourself. The drawback to those doors are that if the door/bldg. faces north (not good in Texas) or a local storm or strong front blows in it will tend to inflate the bldg. and the doors can be lifted out of their tracks and fall into/outward from the bldg. The tracks can also fill with snow/ice and make them immobile.
If you want a powered door,....Some folks like the hydraulic (Hydro-swing is one brand name), because they are somewhat cheaper than bi-fold, but I really have a distaste for them. If you ever see them in even a light wind while fully open....you'll head for the bomb shelter. They really want to fly, shake, rattle, and roll. The hydraulic weren't that impressive for me either.
Same problem with bi-folds. They do not llike being worked/open in wind. Another major drawback to bi-folds is the amount of head-room you lose in the doorway.....up to 3 feet in some designs. The so-called "no lost headroom" models are misleading. They acutally mount OUTside of the bldg. And they also place a lot of strain on the bldg, and require lots of structural reinforcement. (An important consideration in the bldg. design stage, and while your putting your bldg up.)
This will sound like a sales-pitch,....and I guess it is....but you should come see the custom overhead door I designed, and built here for my hangar. Saved thousands of dollars, high winds don't affect it, and simple operation using commonly found items and ordinary house-current. It also only needs 8-inches of headroom.
Also, .....consider the size of it VS the eventual sales value of your bldg. My 44 X 14 opening will not allow lots of twins like some C-414's or 421's which need exactly 44', or if winglet equipped, 45'. And the tails of many twins now in private operations frequently stand above 13'...so again,..the door... Then, as Eric points out...lots of other equipment are stored in hangars. A favorite among those who near retirement-toy ownership...is RV's. The standard max. road height of a large RV is 12'7". So, you'll need your OPEN door to clear at least that. And if you want to store an RV (or eventually sell to someone who does) then you'll want to consider a rear, overhead, roller/rollup door,...which is always good for cross-ventilation anyway when you're working in there during the summer.
Next,....Consider the type of interior lighting you'll want. Flourescent is a nice clean, white, bright, light with low electric bills....but I've always found them high-maintenance. Failed light-tubes, ballasts, makes them expensive again despite the electric bill, and poor start-up in cold weather is irritating. Commercial halide systems are expensive ($200 for a single replacement bulb...not including the fixture), and mercury-vapor, high-pressure sodium are a goofy color and difficult/tiring to work under after a while. Halogen throws off dangerous UV rays and are a fire hazard. (Personally, I ended up just installing common incandescent, ...lots of 100-Watt light bulbs....and am happy. But you need to consider what you want.)
Floor-based heating is virtually out of the question in a hangar due to settling gasoline fumes, so if you plan on a heated hangar, you should think about overhead radiant or forced-air furnace types. Speaking of environmental control.....think also about fire protection like high-volume water spray or deluge systems. Most private owners don't have such systems. I don't, but in some locales you might be faced with zoning issues and bldg. codes.
I used "galvalume" roof panels for max reflectivity, but whatever you use, consider what roof pitch you wish, and why you want it. 12-1 is the most common in the South, but it wouldn't look right next to my home, so I elected for a 12-2. (Twelve feet horizontal to 2 feet vertical slope.) Metal bldgs are usually capable of up to 12-4, and that can be good in high snow-fall areas to keep the roof clear of excess weight, but.....it also makes it exceedingly difficult (and maybe more expensive due to labor safety issues) to construct and dangerous to work on. Hangar roofs don't look that tall until you're up there looking back down...and that can be pretty intimidating. I know. I put my entire roof on myself, and spent considerable time musing about my fear of heights.
Metal roof panels are pretty slippery when dry, you can slide right off them even when sitting down in blue jeans (think about playground slides) , ....and they're downright deadly in the early morning dew.
You'll want to consider skylights. These are semi-transparent panels that allow natural lighting to enter the bldg, which is very dark with everything closed. You'll want ambient light when the electricity fails, or you just want to enter, grab a tool and leave, or otherwise don't want to actually light up the place. (Like sneak out for a beer and escape honey-do lists at night without giving away your location with lighting.)
Seriously, you should consider where you want those skylights. I recommend against in the roof because they are a hail/rain-leak problem and you and your workers can step/fall right through them. They'll support absolutely no weight.
I installed mine in the sidewalls. (Mine are simple panels just like the metal ones, except translucent, and replace four ordinary wall panels.) You might want to consider simply installing shorter-length ones around the upper eaves. That way the are less susceptible to breakage and also aren't easly vandalized if you live in a populous area.
Don't forget to think about roof-peak ventilation. I used the 12' long mechanically openable/closable type. Two of them, one for each 25' of roof length.
Speaking of heights,....don't forget that some day you'll have to get up there to replace light bulbs, and extension ladders are NO GOOD for hangars. For one, they have no sure place to lean them in the middle of the hangar-span...and when they fall (and eventually they
will fall...they are unwieldy when extended and will get away from you) ....they fall on airplanes. Start shopping around for surplus scaffolding. The take-down types are best because they store against the wall compactly when not in use. Get a set of casters and walkboards also. It'll be a good investment for a hangar owner. A good set of scaffolding is a good group-purchase item for a community of hangar owners. I paid $1K for a slightlyused stack-set of 3 tiers with walkboards and casters. If you start shopping early, you might do better than that, but the going rate for a good, used set is about $250 per tier including 1 walkboard. And you're gonna need them during construction anyway if you do it yourself, so don't waste money renting them without a rental-purchase agreement.
A good company I enjoyed dealing with for a bolt-up design is in your backyard, Rhino Steel bldgs. in Denton. They gave me the best bid and delivery schedule for a solid design, and were educational and pleasant. They ship all over, and they'll provide slab measurements for mounting studs for the bldg (which should be placed when the slab is poured. There are after-slab, epoxy systems, but it's better to include the tie-down bolts inherently in the slab, and you'll need those fixtures and measurements before the concrete work.)
There's more, like red-oxide primer treatment for the structure, etc., but I'll quit now. There's enough to digest already. Call me or better yet,...come visit!
P.S. You've seen my hangar. I"ve got about $30K in it not including my own labor of course. Virtually identical hangars 4 miles away (with fewer amenities) cost their owners $65-$75K.
P.SS. R-panel metal panels come in 3' widths. A 50 X 50 hangar will require that end panels be overlapped by 1 foot, and the roof panels are not allowed to overlap due to trapped condensation, so they have to be cut on site and the excess thrown away. So why did I build a 50 X 50? Why didn't I do a 51 X 51? Doh! Oh, Well. Next time.
