Below Slab DC Lines

[Scott Ricks]

I am in the process of building my dream shop. One of my pet peeves has always been having to step over dust collector lines. Usually the ones that are an issue are the ones to the table saw, drum sander and planer since they reside in the middle of the floorspace.

I have purchased a 3hp Oneida cyclone to replace my 2hp bag collector. I am thinking about running two 6" schedule 40 lines below my slab (yet to be poured) and placing them where they will be easy to pipe to the repective machines. I am planning putting in floor plugs to power each so I will not have to run cords.

The distance from the center of the shop to the edge where the line would turn up to the cyclone (in another room) will be about 15'. I am not really too concerned about plugging, and I can put in a clean out under the cabinet (close to the edge) and on the end next to the cyclone.

Anyone have any thoughts about this? Just looking for a nice clean install of machines and DC lines.

Thanks
Scott

[Glen Blanchard]

The vacuum lines in dental offices are run in this manner - under the slab. I, too, like the clean install that such a configuration would provide. My biggest concern would be the apparent inflexibility of this arrangement if you ever decided to move that particular tool to a different area of the shop.

[Jeff Lien]

Hey Scott,
I just built a new shop and and I ran 6" under my slab to the same tools, table saw, drum sander and planer, along with 1 1/2" to power those machines, also ran some other lines too. It has been almost a year and it has worked fantastic, no regrets. I was warned by several people not to do this so preplanning and research was a must. It payed off, all my dc and power lines are invisable and nothing to trip over. I'll post some pix if I get time. remember preplanning is a must!!!

Jeff

[Rod Sheridan]

Hi Scott, you certainly can run your piping in the slab if you plan carefully.

That said, many pieces of machinery accept overhead drops equally well.

Regards, Rod.

[Peter Quinn]

I would do it if I could start over. With cleanouts/access at both ends of each buried line should be no problem. I'm guessing thin strips of solid wood from the table saw getting stuck in a line would be the only potential problem. Anything else would be easy to snake in the unlikely event of a clog. Long radius bends on the TS line might be a good call.

[Ken Fitzgerald]

I'm currently installilng my DC lines. As someone else said, the only drawback is moving tool positions. With a little well thought out planning, under the floor for electrical and DC lines would be the ultimate solution IMHO.

[Steven Wilson]

Instead of running your lines under your slab run a U channel down you slab that's large enough to accept your DC pipe and conduit (say 8" or so). At the top of the U channel form lips when pored so that later you can cover up the channel with steel plate. This way you can customize the length of the pipe in the channel (to accomidate location changes) as well as having full access to the pipe when needed.

[Ken Garlock]

Hi Rick. When I built my shop, I had an 8"X8" trench put down the middle on the slab. I ran 6" PVC pipe in the trench, then up the wall to the ceiling and over to the cyclone. Using couplings, Elbows, and wyes I ran the PVC right up the dust port on the Cabinet saw, router table, and jointer. I have room to install a planer by just cutting into the PVC and installing a wye. The tools are stratling the trench. I also ran my 240V power in the trench with junction boxes at each tool, and a twist-lock disconnect on each tool drop.

When the trench was poured, I had an 1/8" deep by 1" wide lip put into the two top edges of the trench. That allowed me to get 1/8" diamond plate cut to the exact width, and various lengths to cover the trench at slab level.

To handle the band saw and miter saw, both are positioned against the south wall, I ran 6" PVC along the top of the wall with wye drops to the tools.

Oh yes, the slab is constructed with in-ground concrete piers, and post tension cabling.

[Greg Funk]

When I built my shop I had it pre-plumbed with spiral piping under the slab. Most of the outlets are near the wall with a few in the middle of the floor for the tablesaw and planer. Just put in a few extra outlets and you should be fine. I have 3-4 extra outlets which are just plugged for now. I much prefer the clean look to pipes running overhead. I've been using for 5 years with no plugs and I have an undersized cyclone.

Greg

[Tom Godley]

Ken:

By in-ground concrete piers - are you speaking of extra footings that are placed so the slab does not sink?

What is "Post tension cabling" -- in a slab ??? I think I have heard of it for a bridge???

[Steve Clardy]

When I built my shop I had it pre-plumbed with spiral piping under the slab. Most of the outlets are near the wall with a few in the middle of the floor for the tablesaw and planer. Just put in a few extra outlets and you should be fine. I have 3-4 extra outlets which are just plugged for now. I much prefer the clean look to pipes running overhead. I've been using for 5 years with no plugs and I have an undersized cyclone.

Greg


Ditto. I put in several extras also. I use one for a floor sweep.;)

I had a learning curve when I first used my under slab piping.:o
I found that pine, when surfacing, produces long slivers, instead of wood chips. I plugged my system several times before learning to not just hog off the pine material with my 20" planer. I eased up, and allowed the pine slivers time to move through the system.
I also had a undersized blower.
3-4 years ago I upgraded blowers. I never plugged the pipes since.

If I was to do it all over again, I would still go with underslab piping.
I hate tripping over hoses, extension cords, and generally have a shop looking like a jungle with hoses and such hanging from the ceiling.

[Cliff Rohrabacher]

Instead of running your lines under your slab run a U channel down you slab that's large enough to accept your DC pipe and conduit (say 8" or so). At the top of the U channel form lips when pored so that later you can cover up the channel with steel plate. This way you can customize the length of the pipe in the channel (to accomidate location changes) as well as having full access to the pipe when needed.

What Steven said. And consider clean outs spaced appropriately so you can deal with things that get stuck.

[Tom Veatch]

...
Anyone have any thoughts about this? Just looking for a nice clean install of machines and DC lines.
...

My shop is over a crawlspace, but the principle is much the same.

When I was building, I really wasn't sure exactly what the final tool arrangement would be. So, after the joists and beams were in place, I installed a grid of 6" S&D along with electrical wiring such that there are multiple access points with no point in the shop more than 2' to 4' from DC and electrical access.

So far, that's worked very well for me. Admittedly, I could have gotten by less expensively with a detailed shop layout guiding the location of the access points, but this way, I'm not locked into a fixed location for every tool, don't have extension cords or DC piping all over the place to trip over, nor do I have piping/electrical drops to interfere with material movement above the tools. I just wish I'd had the forethought to run pipe for compressed air at the same time.

[Scott Ricks]

Wow. What a great idea. I never thought about the trench. It gives the ultimate flexability. I have been "sweating bullets" over the best layout. Now I can move forward without that worry.

Thanks!!!

Scott

[Steven Wilson]

Ken, did you make forms up for your trench or have the concrete guys do it? Since you've done this before it would be nice to share how you formed the trench.

[Kirk Poore]

Ken, did you make forms up for your trench or have the concrete guys do it? Since you've done this before it would be nice to share how you formed the trench.

In addition, I assume you put some drains in the trench, too. Did you do several, or just slope the trench and put in one?

Thanks...

Kirk

[Ken Garlock]

Ken:

By in-ground concrete piers - are you speaking of extra footings that are placed so the slab does not sink?

What is "Post tension cabling" -- in a slab ??? I think I have heard of it for a bridge???

Yep, you got it Tom. The piers are about 12" in diameter and about 10 ft. deep. They are filled with concrete up to where they contact the slab when it is poured. The piers give extra support to the slab in our crumby soil that likes to expand and contract depending on the time of year.

The post tension cable system consists of cables, as big around as your thumb, that are laid down before the slab is poured. About 2 weeks after the pour, the cable are put under high tension and retainers that look like little cones are wedged into the concrete around the cable to maintain the tension. The piers provide vertical support and the post tension cables provide lateral support. This soil movement plays havoc with slab foundations. The soil is bad enough that no one builds homes with basements.

During the hot dry summer time I have had cracks in the ground around our 5 acres that you could put your hand in up to your elbow. You don't want to do that since the cracks can be or are homes to poisonous snakes and tarantulas. Yuck!

[Ken Garlock]

In addition, I assume you put some drains in the trench, too. Did you do several, or just slope the trench and put in one?

Thanks...

Kirk

I had the concrete people build forms before the pour to make the one level trench down the middle of the shop. They also put the lip on the top of the trench.

No need for a drain. The slab is on a surface that is slightly above grade, say about 6". The early spring before we built, I had a local excavator move around the dirt in the area where we wanted the house and shop/garage. He leveled the area, and made sure that the areas where the two buildings were to be had good drainage. We than had about 3 months for the spring rains to settle the soil before we built. At the end of the build, the man who did the final grading made sure that the soil drained away from the the buildings. We don't get much rain, about 32 inches per year as I recall. When we do get a heavy rain, it does cause flash flooding because the same soil that causes the foundations to move, also does not absorb water easily. Not a problem for us as we are on high ground.

I think I was not clear regarding the trench. It is NOT open to the ground, but rather has the normal concrete bottom just like the floor of the slab. The post tension cables run under the trench just like they do for the rest of the slab . The trench along with the shop floor are painted with Sherwin Williams two part epoxy.