new house with shop

[lopez]

I'm planning my new house now and want a reasonable size shop (16'x25') for a hobbyist. It will be used for making cabinetry, and furniture. I use water based products for top coats so I am not planning on explosion proof fans etc...

My chief concern now is the floor. I was going to use a slab on grade with overhead ductwork for the cyclone etc. My other half wants me to put it over a crawl space with joists and a plywood floor just like the remainder of the house. If I glue and screw the floor it should be pretty stiff and, that way, the ductwork and electrical lines will be under the floor. This approach seems expensive for a hobby. But more importantly, I am worried about the weight of the table saw and the vibration from it and other equipment. I've thought about bringing up a footing under the saw - assuming I will not move it after it is in place. Is that adequate? What about electrical boxes in the floor. Won't they just become sawdust collectors?

Any advise is really welcome. I really would hate to have to tear this thing up after I get it done.

Len

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[Swingman]

Not big enough ... make it at least 18' X 25' if you can. Bigger is better, so stretch every foot out that you can, while you can ... you will be glad you did. DAMHIKT

Pier and Beam construction will work fine, if done correctly. A wooden floor is _much_ more pleasant to work on.

What about electrical boxes in the floor. Won't they

A few with spring loaded covers may be OK, but I shy away from too many floor mounted electrical receptacles and duct work because you will eventually want to move things around and they dictate what you can do more so than wall or post mounted. A few won't hurt, however, and having a crawl space to run wiring and ductwork is handy.

Just my .02 ... good luck on your shop.

[David Babcock]

Not sure if floor outlets are legal anymore?

Dave

[Bridger]

I bought a building with slab on grade. The stability is nice, but there are a few things I'd like to be different. It will take sawing concrete, but I will (sooner or later) cut a channel and run 4" dc, iron pipe for air and conduit for electricity to a point in the center to serve the table saw and work bench. With a suspended floor this would be a LOT easier.

Parking structures for cars can be built with joist/deck methods. Are you working with an engineer? They can spec a floor that can carry whatever machines you might want. Note that stiffness and load bearing ability are not the same thing.

Electrical outlets in the floor do fill with sawdust. My plan at this point is to make a single box in the floor with a flush cover should the use of the building change. In it will be a single 220 receptacle for the saw, a single 110 receptacle which will feed a row of outlets tucked under the overhang of the bench and a dust extraction port. Since I won't be plugging things into or out of the devices in the floor often I can use tape of something to seal dust out of them.

All other machines are either located around the perimeter of the room or are on mobile bases and get used in various locations. Bridger

[Swingman]

Granted, there might be different rules for "shops" and industrial buildings, but they are commonly used, and legal in most locales, in homes ... particularly in living rooms and dens for end table lamps, etc.

Probably safer than stretching an electrical cord across a pathway. :)

[Edwin Pawlowski]

Check the codes on floor mounts. It may be just as good to have a piece of pipe protrude from the floor for about 12" and mount the receptical on that. It still save a wire across the floor. Your electrician should know the codes on that sort of thing. Ed

[Kudzu]

If at all possible enlarge that space. I am building mine and its a 30 x 40 basement. It's a bit large but I wanted a place to work on cars as well as woodworking. I used a 20x 20 garage and building a bookcase it took all the space. I ended up moving the carcass outside several times to work on.

Typical framing should be more than adequate. But the simple thing to do is ask you builder to cut the joist spans in half in your shop are. Or even your could cut the joist spacing down from 16" to 12". Beefing up your floor framing in the shop area would be simple and cheap when it is being built. Probably no necessary but you won't regrett it. And it shouldn't add more than a $250(?) to the cost of the house if that!

Put you outlets in the wall around 4'6" high or somewhere along that. There easy to get to and ablove any benches you add. And be sure to include some

220V outlets too!

[Stephen M]

Vibration? Not an issue. to transmit that vibration from the floor to the rest of the house, it would have to vibrate the sill which is bolted to the foundation. That should dampen most of it.

Support for heavy machinery in the center... that depends on the size of the floor joists and the span. Don't overlook the possibility of steel beams. I found the steel beam that I used under my second-floor shop to be both cost effective (halving the span allowed for much smaller joists) and rock solid.

As for dust collecting outlets in the floor... I'm not a fan of floor-mounted outlets, but what I did for my CS was to mount the outlet IN the floor (not on the floor, but on the side of the floor joist) under a 4x5 cover with a hole just big enough for the cord. I just feel a little safer with the business out of the way if an accidental kick or shuffling of equipment made contact.

I have one DC run in the floor.... It's nice.

The crawl space option sounds like a significant step up in cost, but it will provide a much more flexible and comfortable space.

-Steve

[Jon Endres, PE]

I'm replying prior to reading any other replies to your post, but I'll bet my advice to you is contrary to most of what you'll get. I'll find out later.

My new shop will be 24 x 40, with radiant floor tube heating. I thought about putting in the crawl space/joist approach, with dust collection and wiring underneath, and discarded the thought for a couple reasons.

One, if you have a problem or a clog, you gotta rip up the floor to fix it. Not good. It's much easier to surface mount the wiring and dust collection up high, plus, in my case, I can park a vehicle in the shop to work on it if I absolutely have to. Can't do that really easily with a wood floor unless you design for it beforehand.

Two, if you want wood floors, it's simple to lay down strapping and screw some plywood or T&G pine down to the strapping. I plan on painting my concrete floor with a good epoxy paint with some grit in it, and then putting in some thick rubber mats, like used in horse stalls.

Electrical boxes in the floor would definitely become sawdust collectors, even with good dust collection, and besides, you really want to bend down to the floor every time you need to unplug something?

One idea - if you know where your tablesaw is going, or any other machine that will have a known place in the shop and not be near a wall, you can run a piece of PVC pipe with elbows under the floor slab, with a stub up out of the floor at the saw and at the wall. Basically, a horizontal piece just under the slab. That way, you don't have to run a drop from the dust pipe, you can run the dust pipe right to the wall stub and hook the saw up to the floor stub. If you know you'llbe moving the saw around, you can still do the pipe thing, but cut the one in the center of the floor off flush, and just use an adapter and a flex hose. It'll prevent you from tripping over a floor hose, or letting a ceiling run get in your way.

Jon E

[Roy Neudecker]

Len,

You might think about laying down two layers of plywood running in opposite directions. It would add extra rigidity and strength.

I'm not an electrician or expert on code so take this suggestion lightly. But I often thought if I were to have a wooden floor I would run the conduit up through the floor a short way and the box would be vertical off the conduit. The reason is a round hole is much easier to plug then a rectangular box size hole. And yes the boxes in the floor I've seen are dust, dirt and anything else catchers. Another reason for being off the floor.

Roy

[GrayFox]

I agree! My shop is 20' x 30' with a little half bath in one corner with an industrial sink in it. I was sure it would be big enough, but it ain't. Although can ANY shop ever be too big?

I left my floor just the concrete slab. WRONG! You really need something whether it be 99 cent per sq. foot hardwood flooring or the cow or horse mats. I bought a cow mat, cut it in half and located the pieces where I do a lot of standing and it helps immensely. It wouldn't be a bad idea to cover the entire floor with them.

I had 9 boxes put into the floor and I love them! Sure they collect sawdust, but the sawdust vacuums up easily, and they are SOOOO handy!

My dust collection system in another story. I keep my shop vac in the center of the shop and just connect it up to whichever tool I happen to be using. I also have a squirrel cage blower air filtration unit I built which helps keep the fine dust down.

Someone made a good point about clogs in the pipes if you locate the ducting in the concrete, but a channel grid sustem might solve that problem pretty easily.

I don't think you mentioned anything about lighting. Put in LOTS of ceiling light fixtures an different banks so you don't have to light the whole shop if you are just using a small part of it. I have 30 fixtures in my shop and there are STILL places where I need auxillary lighting. Don't let anyone talk you out of any light fixtures.

Good luck!

[mike]

Listen to your other half, she's right. Wooden floor is comfortable and warmer. If the floor is designed correctly , any machinery for the home shop can be placed on it without any concerns. I used engineered I joists over a twenty foot span, with a beam down the center. This gives me 10' -0" between supports. Joists are 16" centers with 3/4" OSB glued and nailed. I added 1/4" luan plywood on Osb after shop was done. If I had used Advantec for the sheathing the under layment plywood would not be neccessary.I did not know about Advantec until after I had built the shop. I have two boxes in the floor, one 220 volt for tablesaw and a duplex

120 volt for dust collector and joiner. Forget about adding footings for machinery, make sure you have an architect or engineer either do the drawings or go over what you draw up.

mike

[Renata]

Bigger!

And the advice to find someone who can spec out a floor is excellent.

Personally, I agree wood is nicer (though if cost becomes a _real_ issue, concrete is tolerable) and having the crawl space to run wiring, etc. is good. They make wood trusses as well as other means of carrying a load suitable for your needs (which shouldn't be nearly what a garage would require, but more than a standard residential floor).

Renata

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