Help me design a hut/shed for my air compressor

I have an 80 gallon 2-stage air compressor, and it takes up a lot of usable room in the shop and makes a bunch of noise. OK, it's not as bad as some of the little oil-less ones, but it's still annoying. I am thinking about building a little hut/shed next to the shop to put it in. Approximately 4' x 4', not a lean-to style but freestanding to keep vibration separate, with a residential out-swing exterior door to enter it so it has weather stripping and a sill and sweep to keep noise in and bugs out.

Should I do a wood or concrete floor? I'm thinking some bag concrete, mixed up in buckets with my drill mixer, poured over 6" of gravel would be fine. Any problems with that?

I would probably do a shed style (single slope) roof with asphalt shingles to match my existing shop roof. I would want some kind of guttering or way to keep water from crashing down off of it onto the ground and making a muddy mess of the front of the shed and door. It seems silly to put in a full gutter and downspout for a little 4'x4' shed though. Suggestions?

It gets cold here. Not northern Minnesota cold, but still well below freezing. How do I keep from cracking condensate fittings in the tank? A 100w incandescent bulb on a thermostat? I'm planning on insulating the shed to control noise; would the heat of the air compressor keep it defrosted? I could put an auto-drain on it, either the style that goes off on a timer or the kind that cycles each time the compressor shuts off. Would that be enough to keep from cracking fittings?

I would need to provide for fresh air intake to feed the compressor. I was thinking about actually ducting the intake from the outside through a muffler. I also need to keep the air compressor from overheating - should I just plan on large volume fresh air flow while it's running, to both feed the compressor and cool it? I need to worry about insects so it would need to have grating and probably forced air flow (ie, a fan) to overcome the restriction.

What else should I think about putting in the shed? I want to keep it simple, but considered adding dust collection / central shop vac to it - or at least room for it later. That's another space consuming and noisy thing that would be nice to have separated from the shop itself. Anything else?

Any other suggestions? Too much work for 9 square feet of shop space? Thanks!

I do think that's too much work. Not so much to get it out of the shop, but in protecting the compressor itself. I would slope the roof off a different side than the door will be on and not bother with guttering. I wouldn't bother grating or filtering or even weatherstripping anything. What's the most dangerous bug you're worried about? Around here the only thing i could be bothered to worry about is bugs nesting in the air filter housing. You can put window screen over that thing i guess. A heat lamp on a thermostat would be the easiest way to manage the heat, but once the compressor ran a bit it would probably heat its little shed enough to turn off the lamp anyway. My main consideration for cold-proofing the compressor would probably be to put thinner oil in it and forget everything else. 

I know Texas is Texas and nowhere else is Texas but around here there are a ton of shops that keep their compressors outside under lean-to roofs (and usually a chain link enclosure mostly for vandalism/theft reasons) and it does freeze here every single year and i've never once heard of a freezing related compressor issue. 

+1 on a lot of what Vigo says.

Here in TN, I built a Pole barn style lean-to for my compressor. The drain was a gripe, sounds like you have a plan for that.

My thing was it got HOT. I have since sold the house, but I was considering a fan in, mounted low, and one out up high on the opposite wall. I dis 4X4', tiled the concrete (idiot!), and enclosed it with walls.

Since then, I've checked out several tire shops. The Quincy compressors they all seem to use have huge fins. They are enclosed on three walls, plus a roof, and cause me much longing. 

YRMV in respect to heating. Mine ran well into the 30s

Fair enough, I'm sure I'm overthinking it. But the bugs thing wasn't so much a danger to the compressor just a "gross, dealing with 1000 spider webs" thing. We have 3.5 acres, and lots of bugs and wildlife that come with that. I'm constantly fighting bugs and spiders in the shop and would rather my air compressor shed didn't turn into a terrarium.

Also, 30s would be the high or beyond the high many days in the winter here. 30 degrees you don't really risk cracked pipes. 0 degrees and even formerly trouble free pipes can end up cracked. I lost all the copper in my shop due to a failed flame sensor on my furnace during the wrong week. Pretty much every pipe froze and split. I'm hoping not to recreate that with the drain piping on my compressor, but i bet an auto drain would be enough.

I'll need to think about the airflow thing. It'll need fresh cool air I'm sure.

There’s a good thread here https://www.garagejournal.com/forum/showthread.php?t=208171

The photo is from the thread, I built mine just like it.

Be careful you don't end up without enough air circulation to keep the head and electric motor cool enough during summer.   I've seen cases where the compressor keeps overheating and shutting itself off when they've been boxed in.

I would put four walls and a roof, but leave plenty of open space under the roof.  Usually that is the eaves with rafters.  This lets the heat escape up above, but sound will come out there, so maybe a deflector before the opening.  I rewired mine when I put it outside with a remote switch, so I can turn it off at night when it goes on realizing I left it on.

An actual timer would be better, or even a 'occupancy sensor' switch so if you are in the garage and moving it stays on. 

How about rigging up an exhaust fan that comes on with the compressor. That along with plenty of air intake opening lower down. Like Not A TA said, compressors will get hot and shut off if not enough airflow. A deflector/baffle just behind any openings should cut down noise outside the shed, just leave enough gap for airflow.

This is my compressor shed (don't mind the fence I'm fixing):

It is 5.5 x 5.5', on a PT 2x6" base and PT 3/4" ply floor, with 2x4" construction, insulated floor, walls and ceiling. The door is 2x4" construction, and insulated. It's sitting on those concrete deck post things.

I ran 220V 8/3 wire from the breaker panel in the shop, to a sub panel in the compressor shed.

From the compressor shed breaker panel:

• 110V goes back into the shop, to a wall switch by the door, which comes back into the shed and activates a 220V Contactor which connects/disconnects the compressor (5HP 2-stage).  This 110V ALSO activates a bathroom fan on the ceiling (make-up-air vent on the bottom), and ALSO activates an automatic tank drain.
• 220V goes to the Contactor to run the compressor.
• 110V (another leg) feeds a constant outlet inside the shed, as well as a switched light.

Inside the shop, if if you aren't making any noise, you can just barely tell that the compressor is running.

The tank drain might scare the neighbours.

I'm not necessarily recommending this, but i work in the country too and deal with all kinds of bugs, some of which are mildly dangerous. If i need to clear out an area i just sweep fire through it. Propane torch and brake clean, but you can do it however you want. I know people are sensitive about fire so you'll have to make your own call on it, but I can blow fire at almost anything and in 99.9% of cases it's going to take longer to damage something (let alone actually have it catch fire and keep burning) than it does for bugs to die. Their surface area to mass ratio is complete E36 M3 for surviving fire. 

Like i was saying about your compressor intake, the only bugs im concerned about down here are the ones that pack orifices with eggs and food and plaster over it, thus blocking the hole. I've had a freshly built engine fail to spin after mud daubers built a nest inside a cylinder. It took me installing the engine to figure it out the hard way. 

The scorpion that died inside the instrument cluster of my turbo caravan was far less annoying. 

In reply to SkinnyG :

Thanks, that shed looks great!

@Vigo: I love the scorpion shot. Hope that wasn't a pain to remove.

Yep...  My compressor shed is basically a glorified pallet lifted of the ground...   about a 7x7 space used for piling wheels and tires, gasoline and a few other things.   repurposed lumber wrapped in some recycled corrugated metal..  Open soffits keep it vented..  Cold here in KS has never been a problem.  and the compressor has been living happily out there for nearly a decade.

Found an inside shot.  Not super detailed, sorry.

I kept mine in the shop because I frequently work well into the evening and didn't want to piss off the neighbors with the noise but I build a closet for it up in the rafters.  I thought it would shake like he!! but it really doesn't and I barely hear it down in the shop, haven't gone though summer heat yet though so the final verdict is still out.

My previous compressor was a stickered 5hp (probably 2 or less) oilless that was loud enough to kill people and wake them back up from the dead and do it again.

I had it off the back of my house garage, in an insulated 2x4" extension.  It was still loud enough to hear, but you didn't want to hatchet murder anyone because of it.

I would never buy an oilless compressor again.