new shop questions

[Paul Saffold]

My new(est) shop will be an attached garage 24’x24’ with 10’ ceiling.

I am really excited to be able to have my tools out of storage. It has been too many years.

I have followed along with other’s shop builds for ideas.

My game plan is to have the StabLoc service panel replaced, add outlets (20A 110v and 30A 220v), insulate walls and ceiling, drywall, 4’ LEDs (Costco), mini-split, sleepers and rigid foam covered with some kind of sheathing for the floor.

Looking for advice about a few things.

Should I use pressure treated for the sleepers? Should I run the sleepers right out to the overhead door? Or leave a gap of a foot or so?
Suggestions for what sheathing/underlayment to use. That will be it for the floor so I’m not looking for a finished floor.

What if anything should I do with this area? Fill the holes in the bricks with mortar mix? Cover the bricks with 1x? Leave as-is?
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There is a gas hot water heater and a water softener in the garage. Any preventative measures to deal with water leaks? They will be on the existing cement floor.

I am doing everything except the electrical and drywall. 10’ 1/2” sheets are too heavy and awkward at my age.

I’m sure there will be more questions as I go along but this is about getting the room ready.

Thanks for any suggestions.

[Jim Becker]

That will be a very nice space and the 10' ceiling is a real bonus compared to most "gara-shops".

Yes, you want to use PT for your sleepers as well as any bottom plates necessary for your wall structures that support the wall finishes. Since you are putting in a floor for both comfort and presumably to level it (!), I'd take it right to the overhead door(s). Advantech or the LP equivalent are good choices for the flooring, IMHO, as an alternative to plywood. Put foam insulation between your sleepers. If there's more than one overhead door, I'd also likely put a false wall in front of that to provide more shop wall space, leaving one door for access, but it sounds like from your text that there is a single door. If there's an opener in the middle of the ceiling, consider replacing it with a wall mounted unit if your door has a jackshaft that permits using that kind of opener. Yes, there's a cost involved, but it clears up more overhead space so lighting, etc., isn't blocked. I did that in my temporary gara-shop (needed a new opener anyway) and it was remarkable what losing that ugly thing in the middle of the ceiling as well as the center chain drive did for the space.

The walls in my new shop building going up soon are also 10'. My plan for that space is to actually use 4x8 drywall installed vertically and the do sound reduction accommodations with acoustic tiles for that top two feet rather than drywall.

For your electrical, do more than one 120v 20a circuit and consider more than one 240v 30a circuit so you have flexibility to be able to run a 240v dust collection system at the same time as a 240v tool. In my old shop I kinda went crazy "back in the day" and had a whole bunch of 240v circuits, but have simplified things for the new shop. Only tools that require a dedicated 240v circuit (DC, CNC, minisplit) get them and the remainder of 240v tools connect to a common 240v 30 amp circuit with multiple outlets.

[Gary Ragatz]

I think I'd put drain pans under the water heater and softener, so that if either one starts to leak, you don't end up with that water on the floor of your shop. Have the pans drain outside the building or to a nearby floor drain, if that's convenient. Might need to check if there's building code that covers this in your area.

[John K Jordan]

I think I'd put drain pans under the water heater and softener, so that if either one starts to leak, you don't end up with that water on the floor of your shop. Have the pans drain outside the building or to a nearby floor drain, if that's convenient. Might need to check if there's building code that covers this in your area.

After paying for a the aftermath of water heater leak I mentioned to my insurance agent I was going to put down a pan. I showed him one I found without an external drain but with a detector. Said he was planning to send that info to his clients.

[Ed Aumiller]

Recommend putting a 120v outlet on every stud if 24" centers or every other stud if 16" centers... make every other outlet on a different breaker.. use GFCI breakers (or a GFCI outlet on the first outlet, my preference)... Put at least 2 240v outlets on each wall (4 ckts total)...
This sounds like overkill but it is easy and not that expensive to do it before covering walls.. and a pain to do it after walls are done..
You never know where the tools will be located then relocated, etc...

If code allows it, put some floor outlets in the middle area since you are putting rigid foam under floor... you will find them handy and better than extension cords from walls for your tools...

[Jim Becker]

Honestly, I've found that 120v outlets every 4-6 feet is more than adequate in the shop other than, perhaps, specific situations where a bunch of things, like chargers, etc., need to be all plugged in simultaneously.

I like the suggestion about considering having power available in the middle of the floor and am considering that for my new shop building, but I'm still on the fence about that.

[Charlie Velasquez]

My new(est) shop will be an attached garage 24’x24’ with 10’ ceiling.

….. sleepers and rigid foam covered with some kind of sheathing for the floor.


Suggestions for what sheathing/underlayment to use. That will be it for the floor so I’m not looking for a finished floor.

Thanks for any suggestions.

Forego the sleepers. This was common to support your sheathing, but technology for insulation panels have come a long way. Owens Corning Foamular sheets have compressive strength of 15-100 psi. At 144 sq. in. per sq. foot, even the 15 psi clocks in at over 2,000 psf.
The problem with sleeps is at sleepers at 16” o.c., and perimeter boards about 25% of your insulated floor will have an R-2.7 as opposed to 8.75. And you really don’t gain much with respect to compressive advantage. Just lay the foam down and cover.

Wrt the sheathing, I am completely sold on Advantech osb. When I built my shed I hurt my back before I could get my roof on. The shed floor sat exposed for all winter and spring; snow, melt, snow, melt… rain, rain, … When summer rolled around not one seam puckered, no screw holes flowered, except for some dirt it looked the same as the day I put it on.

If you have any concerns, go with 25psi or higher foamular panel and upgrade to 1” Advantech panels.

[Jim Becker]

Forego the sleepers. This was common to support your sheathing, but technology for insulation panels have come a long way. Owens Corning Foamular sheets have compressive strength of 15-100 psi. At 144 sq. in. per sq. foot, even the 15 psi clocks in at over 2,000 psf.
The problem with sleeps is at sleepers at 16” o.c., and perimeter boards about 25% of your insulated floor will have an R-2.7 as opposed to 8.75. And you really don’t gain much with respect to compressive advantage. Just lay the foam down and cover..

For a level floor, I absolutely agree...no sleepers needed. But for a sloped floor that you want to be level...sleepers are pretty much required.

[Paul Saffold]

Jim, Yes it is an 18' door. Budget doesn't allow for changing the door opener. I will have 3 110v circuits with outlets staggered so there are not 2 outlets on same circuit adjacent.
I was planning on not leveling the floor. I'm not sure how I would go about that. Cabinets would be built onto a leveled base.

Gary, thanks for the pan suggestion. Hadn't thought about that.

Ed, I like the idea for floor outlets.

Charlie, no sleepers sounds much simpler but how do I attach the sheathing? Nailing through sheathing and foam panel into the garage floor? Construction adhesive to attach the foam to the floor and more adhesive for the osb to the foam?

I appreciate all the comments.

[John K Jordan]

I like the suggestion about considering having power available in the middle of the floor and am considering that for my new shop building, but I'm still on the fence about that.

How about at the middle of the ceiling? I installed some receptacles in the ceiling and mounted some retractable cord. I'm surprised at how often I use them, not for permanent things of course.

[Jim Becker]

How about at the middle of the ceiling? I installed some receptacles in the ceiling and mounted some retractable cord. I'm surprised at how often I use them, not for permanent things of course.

Yes, that's actually the way I'm leaning at this point. Circuit(s) to a big j-box "up there" and then I can place (and easily move later) proper strain relief drops to twist locks that I'm standard on. I have to drop DC from up above already, so doing the electrical that way provides the same flexibility over conduit in the floor which is "permanent". The same would be true if I were setting up a garage based shop like the OP as the method I used for the temporary shop ("drive over cord protection" from the wall to under the CNC) isn't practical for long term, for example.

[Ed Aumiller]

You really need to level the floor if at all possible... You never know when you will want to arrange the tools, benches, etc and if floor is not level, it can be a pain.

When my shop was built (1992) the crew who was to do the concrete floor did not show up!!! I had many loads of concrete in my driveway that had to be unloaded..
Went ahead and poured it with the help of a friend but it was very uneven. After I finished the exterior, I took fine sand and leveled everything out then put 1/2" plywood down for a floor. Used cement nails to tack the corners down. Still level and no problems 30 years later.

Depends if and how much your floor slopes but should try to get it level if you can. Sure there are many ways to do it, hopefully someone will chime in with good ideas for you.

[Jim Becker]

I agree with Ed...it's worth the effort to level the floor, particularly when a new floor is actually going in above the original concrete like proposed. It solves many problems over time. I just lived with a sloped floor for over 20 years and am SO glad to be getting away from that with the new shop building!

[Paul Saffold]

The floor slopes 2.5" in 24'. It has been painted at least twice judging from the colors.

[Tom Bender]

Use some type of cement based floor leveling material. Even very weak lean concrete will work. Sure it will have to feather out at the edges which would result in failure in a normal application. Then put down 3/4" foam then your flooring. No need to fasten it down. Some kind of T&G edge connection would be best. In NC you don't need a lot of floor insulation.

A nice Oak 1 x 4 with a bullnose will look great over those bricks. It will protect your drywall from a lot of scrapes.

You definitely want your lights on their own circuit so the table saw can't put them out.