1. Go as big as you're allowed to per zoning. Literally no one has ever said I wish my shop was smaller.

2. Pay for extra insulation. It'll make it more comfortable year round wether you put in heat or AC or not. Put in way more electric sockets that you think you'll need.

3. That's up to you and what's readily available in your area. I have a pole barn style shop. My boss built a metal "carport" style building but had it enclosed, both seem to be just fine, though mine seems to have less leaks except during hurricanes.

Lay out some garden hose or extension cord in the rough size and location in your yard, park your project and or other vehicles in that area to see how much space they use and where you want to put workbenches and stuff. You can also figure out where the lift will go so the concrete guys can be made aware. That way the appropriate depth and reinforcement can happen in that area.

 

You need to know high the lift will go. The one I have I can walk under without bending over and I'm 6'2'. Then add in the Hight of what you are going to work on, I needed 15' clearance in the middle of the shop to stand up the lift, so I can lift vans and large trucks. It's also a 12K rated lift.

 

I had a 30 x 30 with 10'3" walls. It fit 3 project vehicles, lawn and garden equipment, work benches all around, etc. go as big as you can.

 

With the termite problems in fl. ,I'd consider an all steel building . The 4post lifts don't require concrete footings or a thicker slab .a gable roof will allow a lift in the center without excessively high sidewalls . Plastic pipe & conduit are cheap , put in plumbing for a bathroom , 2"-3 conduit for electrical . 10-12' side doors , double door for lawn equipment . Consider a floor drain .36' wide x 30' deep

 

Generally speaking a 30x40 with 12' walls is a good size and a pretty standard size. You could go 30x50 by the rules. Also a standard size.

Now I'm gonna tell ya something NO one ever talks about. More floor space is nice and everything BUT something to keep in mind. More space, more cleaning. Cleaning is time. Time cleaning isn't time building, time building is slowed down with a dirty shop.
More space is more walking back and forth to the tool box. A guy wouldn't think an extra 10 feet matters but by the end of the job you've gone 10' 100 times. Nearly a 1/4 mile. Tools scattered all over 1500sq ft isn't fun either.
More space and the placement of the big doors and little doors and windows are really important to how you use the floor space and recover its dead spaces. My shop has a loft on 3 walls for storage and a electric hoist(cheap winch) that gets everything NOT used off the floor. 2 12' wide doors spaced 3 feet apart leaves a strip 3' wide that can't be used for much because it's between cars. Windows for natural air flow and a attic fan of vents are noce to shed the heat of summer. Winter time sun is a thing too. Use the winter sun to help with heating.
Electric, plumbing all the things inside can be changed pretty later but it much harder to move a door and service panels so think about he bones
I generally agree a guy can't have too much space, but you can have more space than you can manage.

 

Get a variance and make it taller, or scrap the lift. If you apply for a variance they will send your immediate neighbors a letter. In my case I had my neighbors sign it, and my variance for height went right through. The lift needs prep for the concrete (lotta weight into one spot / how deep, etc???

Mine is insulated with that foil backed bubble wrap streetrod stuff before the metal siding and metal roof went on. Helps with heat a LOT! I have the door on both ends, with concrete approaches. You can add length without the price leaping. If you add width the price starts jumping. I told my GC that I wanted to see the engineering drawing for the trusses (rafters), and the permit that was signed off at the end. I have both. Don't scrimp on concrete thickness, and gravel. Witness the depth, and reinforcement (up on "chairs").

Garage doors are pretty much junk these days. They are like a pop can, and if you are determined you can cut through them with a utility knife.

Get yourself a Tattletail for out there after you are done. I put a fire extinguisher in mine. Hope I never need it, but at least I have something to give myself a chance.

Put a big breaker box in the thing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! A/C system will take up 3 tabs, lights 1 tab, outlets 1 or 2 tabs, garage doors 1 tab. Welder 2 tabs. 220V air compressor 2 tabs. See how quick electric gets used up. 100Amp minimum. Exterior lights on each end might be nice, but figure a circuit for those too. The first GFI outlet on each outlets circuit, wired in series will be much cheaper than GFI circuit breakers. Your GC will not volunteer this electrical advice unless you ask. They don't want you to bail on buying a barn due to first cost.

Putting that gray coating on the floor before you put stuff in there is way easier. However every time you add something it's more money. This will cost you more than you think (experience talking here). Don't buy that pebbled epoxy flooring!!!!!!!!!!!!!!!!!!!!!!!!!!!!NOPE, NOPE, NOPE!

Fill dirt and seed around the edges cuts down on the desirability of critters to try and dig in under the edges.

Sorry if I scared you off Charge556.
Gene

 

For functionality, bigger than you need will always become smaller than you need. Trust me on this. Unless you are the OCD-est person on the planet, you'll need/want bigger. Having said that, in some areas having a disproportionately sized shop can either limit your purchasers to a smaller group, or just plain lower the property value.

I desperately want to have a 40x40, which means I'm shopping for a 60x100. I can't afford either right now, but I like to dream.

10' walls is a very wise choice. If your code/snow load allows the narrow roof pitch, consider 12' walls.

 

I have never met anyone yet that said "I wish I would have built a smaller pole barn/shop". One of the late members in my Model-A club chapter built a second barn, adjacent to his existing barn.

 

I have two shops, 24x48 and 24x36, I wish I had built bigger but was limited by location and property slope. The 24x36 is 14 feet tall at the sidewalls. I have a 24x22 foot concrete pad in front of that shop with two four post lifts outside. Where i live we have long nice summer weather and it's nice to work outside. My 24x48 shop is 9 ft sidewalls and I use it for storage and parking. I built both myself. where I live electrical power is almost the cheapest in the nation, the shops have their own meter. Both shops have 22 110v outlets, about 20 LED lights and numerous welder outlets as well as 5 outside GFI boxes. Can't have enough plug ins! The advice i can give you is if you are building your first shop, go and talk to other shop owners in your area and ask a lot of questions about what they built and how they set up the shop and things they wish they had done different. Most people will want to talk and help you out. An electrical code book is also your friend. Good luck on your project.

 

My dad built a 30x50 barn with 10' walls and the lift was just fine. I built a 20x24 garage with 10' walls and... the lift was fine, except that I was confined to placing it where I'd also have to contend with the 7' garage door. I saved on the builder by having him put in hinged doors, doing the siding and electrical myself... And that worked out fine, but I decided I'd rather have a conventional garage door with electric opener.

Currently, I have a '56 F-100 on one side of the garage and a 4 post lift with a miata on top and a metropolitan on the bottom, and I can open the garage door. But anything larger on and under the lift wouldn't work, and if the truck is on the lift I can only open the garage door if my lift height is enough to work underneath sitting on a rolling stool.

I'd say the 10' height is just fine if you're able to build large enough to be away from the garage door. In my mind, a 12' height would have been better... but that last 2 feet would mean poor ergonomics anyway, and I don't think you really need more than 10 feet height.

 

10 feet door and walls should be ok as long as the center is 13 feet to clear life and vehicle.
This can be accomplished with Scissor trusses.