Shop Air and Electrical in the Floor

Should dust collection ducting and electrical wiring be placed in a slab floor? January 8, 2010

I just broke ground on a new 24 x 36 shop and have a few questions to ask fellow woodworkers.

1. I plan on installing radiant heat in the floor. What do you think about running the electrical and dust collection in the floor? It would mainly be for my large stationary tools and I am pretty happy with the layout so the fact that it is permanent does not bother me.

2. Lighting. I have budgeted in plenty of fluorescent fixtures and skylights but want to make sure I am not missing anything.

Any comments and suggestions would be appreciated. I think I have thought of most everything but want to make sure I do this right the first time. Feel free to add what you would do different to your shop.

Forum Responses
(WOODnetWORK Forum)
From contributor J:
You need to keep that electrical and DC piping accessible. A large shop I used to work for poured the floor right over the DC piping. It worked fine until it developed a leak and began filling with water, at which point is was impossible to fix. Another shop had wood panels bridging a trench down the middle of the shop's concrete floor, with the DC pipes in the trench. This system worked fine.

From contributor X:
Keep your electrical separate. Dust creeps into everything - fire proof it. Ask your insurance agent what he recommends.

From contributor A:
What kind of building are you putting up wood or metal? If I were building a wooden building with finished interior walls, I'd put the electrical in the floor. If metal, I'd use conduit and run it in the top and on the walls.

I'm in MS so we don't worry too much about heat. I've heard radiant floor heat is very comfortable. There's no question, I'd air condition a shop that size. I like contributor J's description of the DC lines in the floor but not concreted in. I've seen that before and it was slick and worked well too.

At every other 110 receptacle, I'd have an air chuck. I'd figure out how many 220 receptacles I needed and put twice that many in. I'd have three phase if I had access to it. I'd figure out some way (lean to, shed, etc) to get the air compressor and/or the DC outside. If your building will have windows, I'd put them at about 60" off the floor to provide for more useable wall space. Ten foot ceilings for sure.

From contributor R:
I would not put dust or electrical in the floor. What seems absolutely finely, brilliant and permanent today will change with the addition of one piece of equipment or tomorrow's more brilliant idea.

I certainly agree with accessibility. Surface mounted conduit is nice. Floor heat is wonderful. If you do this, take lots of pictures. The mesh we used for reinforcing the concrete is /was 6"x6" - probably it's all that size. Anyway, the pictures of the tubing referenced against the mesh and other "landmarks" have enabled us to safely anchor added and moved equipment. Yes to the advice about lots of air chucks.

About agents: I asked my agent when I added on to a steel building (I was just starting in business.) He said it didn't make any difference, until I had it up. Then, "oh, if you had done steel it would have been less expensive." So, pin him or her down.

From the original questioner:
Thank you all for the input. Better to gather all the info I can now than later. The building is wood - 2x6 construction and 9' walls with cathedral ceilings so plenty of headroom. Great idea about pictures of the floor prior to pouring and also the air drops. I run off a digital phase converter for my 3 phase. It works great. I have checked with my agent but think I will call him again just to be clear. I will figure out how to add pictures of the build.

From contributor C:
On the floor heat, make sure you put blanket that will reflect the heat back up into your space. Have someone design your system so it is sized correctly.