Dust collector tube in poured concrete floor?

[Gary McNair]

I'm adding some sq footage to my shop and want to place a short dust collection tube in the new poured concrete floor. Is there a specific material or product for this application?
Thanks,
Gary

[Rod Sheridan]

Hi Gary, I'd stick to PVC for an in slab pipe, no corrosion issues.......Regards, Rod.

[Jeff Nicol]

When I was still doin sheetmetal work before I tore up my shoulders. We would use spiral pipe that had an epoxy or vinyl coating on it. It was directly buried and covered with cement. Not sure if it available near you but sometimes sheetmetal shops have racks of extra left over pipe from jobs if it just a few feet that might work. Does not hurt to check it out. I agree with PVC if it is all you can get.

Good luck,

Jeff

[Steve Clardy]

I used PVC S&D

[Ben Franz]

Whatever you decide to use, it's better if there is at least 3" of concrete under the pipe. In our area back in the early 70's builders were using Sonotubes for under slab HVAC ducting. Most of these systems have had ductwork compromised by moisture and termites because the ducts were exposed to ground without any concrete underneath. Not quite as serious for DC pipes but why tempt fate. Also, consider how you will clear any blockages that might occur.

[Wayne Cannon]

In an interview, Norm Abrams said he wished he had designed-in underfloor ducting for his dust collector, but he had to work with an existing concrete floor.

My preference is to keep everything accessible for repair or change.

[Charles Seehuetter Panama City]

When I was designing our new shop I wanted DC and electric in the slab also but I wanted access to it. Instead of having the slab poured over the pipe I had a trench put in that could be covered with standard treated 2 X 12 lumber. Here is the trench after the pour. You'll also see a drain pipe (partly covered with dirt in this picture) in the end of the building so I can rinse it out if I need to.

http://www.sawmillcreek.org/picture.php?albumid=48&pictureid=414

Here is how it is used in the shop. I am currently using 4" PVC buy will be upgrading to 6" soon. There are also 110V and 220V outlets in several locations along the run. The 2X12's are cut in 4' sections and can be arranged to different locations or replaced as needed. Cutouts and be easily made alywhere along the run. The DC is in a closet at one end and the run extends along the back wall to other machines.

http://www.sawmillcreek.org/picture.php?albumid=48&pictureid=415


More pictures can be seen at.

http://picasaweb.google.com/chuckinpc

Under New Workshop

Just thought I'd throw out this idea as an alternative for you.

[JohnT Fitzgerald]

Charles - that's a pretty nice setup.

has anyone ever retrofitted something like that into an existing concrete floor?

[Jeff Duncan]

The only in floor DC that I've seen and like was where the wood floor was raised a couple feet above the slab. Then you could go down and have access to anything for future needs changes etc.
I've re-arrange my shop too many times to incorporate new machinery to ever stick the pipe in a concrete slab. But that's just me.
JeffD

[Karl Brogger]

My preference is to keep everything accessible for repair or change.

Thats how I feel. In the floor isn't worth the hassle to me.

[Chris Padilla]

In some instances, it seems like buried in the concrete would be awesome and it keeps overhead space clear and I would think it might even be quieter and definately cleaner in terms of looks and space.

On the other hand, you'd have to be extremely organized and know exactly where all your machines will live and hope that you never need to move them or get new machines or whatever. You're pretty locked into where they are located unless you do it in such a way to have access from under the floor.

Lots to think about! I think I'd put them in the floor but only if I had decent access to them under the floor--i.e. a crawl space.

[Tom Veatch]

I put mine under floor in the crawlspace when the shop was being built. In an attempt to address the "where will the tool be tomorrow" question, I laid a grid of 6" S&D with capped off inlets and electrical access points on 8' centers so no spot on the floor is more than about 5½' from an DC or electrical connection point. Shop is 32' x 24'. Figured if I needed smaller granularity that that, I would be getting too crowded anyway. So far, it has worked out quite well. But then, I don't move the tools around much. In fact, all the stationary tools are hardwired through disconnect switches so they are pretty much definitely "stationary".

[Chris Padilla]

Tom,

This BEGS for some pics of your shop!!

[Mark Wyatt]

The only in floor DC that I've seen and like was where the wood floor was raised a couple feet above the slab. Then you could go down and have access to anything for future needs changes etc.
I've re-arrange my shop too many times to incorporate new machinery to ever stick the pipe in a concrete slab. But that's just me.
JeffD

This is how my shop is set up. The floor is raised on 2" x 6" sleepers and the 4" ducting runs beneath. The pattern of the sleepers incorporates runs for the ducting. This does require extensive planning and it is not easy to rearrange. To get to the ducts requires moving machinery out of the shop and pulling up the sub-floor (plywood sheathing screwed down). Then you can tap into an existing run.

Creating a new run requires changing and and re-building the sleeper pattern. It also takes away some height in the shop. The advantages are:

(1) keeps the duct work out of the way and conserves wall and ceiling space which is very important in my 18 x 24 shop.
(2) allows me to run electric under the floor to my table saw/router table in the middle of the room.
(3) I have bad knees and this is a much softer workspace to walk on. Not sure if I could handle concrete well.
(4) If I drop a tool, generally it's no big deal. The floor is very forgiving.

-Mark

[Duane McGuire]

I'm no expert, but I am in the process of building a new shop. I decided to serve two ports beneath the slab. I have used 6" S&D PVC. I used PVC cement to secure the underground joints. The pipe was laid about 6" beneath the slab in the engineered fill. I discussed this with a number of people before acting. As has shown up in this thread, many warn that decisions may change about machine placement. But in my case, I've previously worked in a shop of similar design, and the location of tablesaw and jointer seem right. If they aren't, well concrete is cheap, and I can fill in the inlets. I will be running the other ducts overhead. The under slab runs will serve tablesaw/router table and jointer. Underground lines shown below are in red (DC and conduit)

Here's the shop plan:
http://www.duanemcguire.com/dmc/woodworking/shopplan.jpg

This is the underground duct, fully assembled before trenching and backfill.
http://farm4.static.flickr.com/3176/2686506383_e4a8ba5eea.jpg?v=0

At time of backfill:
http://farm4.static.flickr.com/3052/2694050234_b1b024387f.jpg?v=0

Pouring slab:

http://farm4.static.flickr.com/3087/2709772949_54b27fd868.jpg?v=0

[Tom Veatch]

Tom,

This BEGS for some pics of your shop!!

Chris, my shop is very much a work in progress - has been for long enough for my wife to become convinced that my hobby is not woodworking, it's workshop building. But, if that were the case, you'd think it'd be further along.

I'll try to straighten up a little and get a few pictures posted in the next few days.

[Craig Coney]

Saw cut & Demo. Place ductwork, Dowel rebar & pour.

If I was going to put the ductwork in the floor, I would have trenches like the ones like Charles has shown that can be covered up. I am familiar with industrial ones with diamond plate hatches.

[Mike Malott]

Craig Coney...

I'm really close to doing exactly as you suggest, sawing a 12" wide X 15' section out of my shop floor to run PVC coated 6" spiral pipe.

My question is, how do you drill the holes to dowel the rebar in a 12" wide trench? Is an offset hammer drill available???

Best regards,

Mike

[Jeff Duncan]

Mark, the shop I saw had the floor raised up a couple feet, (can't remember where I saw it though?). Anyway there was a pic of the owner using a mechanics dolly to roll around under the floor enabling him to get to everything without moving equipment or removing the subfloor. I thought it was a great idea if you really wanted to go the extra distance to put the duct under the floor. Personally I have mine running along the ceiling and find it the easiest and best solution.
JeffD

[Chris Padilla]

I'm no expert, but I am in the process of building a new shop. I decided to serve two ports beneath the slab. I have used 6" S&D PVC. I used PVC cement to secure the underground joints. The pipe was laid about 6" beneath the slab in the engineered fill. I discussed this with a number of people before acting. As has shown up in this thread, many warn that decisions may change about machine placement. But in my case, I've previously worked in a shop of similar design, and the location of tablesaw and jointer seem right. If they aren't, well concrete is cheap, and I can fill in the inlets. I will be running the other ducts overhead. The under slab runs will serve tablesaw/router table and jointer. Underground lines shown below are in red (DC and conduit).

Duane,

That is pretty cool! It is great to see the progress pics. After looking at what you did, I think I would go ahead and put pipe in the concrete but I'd still have to have some overhead as well. Worse case, you end up abandoning the underground pipe....

Do you have any recent pics or are those pretty recent? :)

[Craig Coney]

Mike
Drill at an angle with an hammer drill as close to level as you can into the existing concrete, then just bend it down

[Duane McGuire]

Duane,

That is pretty cool! It is great to see the progress pics. After looking at what you did, I think I would go ahead and put pipe in the concrete but I'd still have to have some overhead as well. Worse case, you end up abandoning the underground pipe....

Do you have any recent pics or are those pretty recent? :)

Chris:
Thanks for the comment. I'm so excited about this shop! Been wanting it for 30 years! Yes I have about a million photos. The excavation and foundation were July/August. The shell of the building is now complete. I will need to do heating systems (radiant floor heat and woodstove) before the DC system. Winter is coming. Just about to plumb the gasline for the primary heating system -- floor heat! If you'd like to see more photos of the project, you can find them here: http://blog.duanemcguire.com/photos-main/

[Bob Winkler]

Duane, I loved your blog and pics. I'm in the planning stages and was wondering where your shop plans came from (self drawn, architect, builder, etc). I may steal your idea of a separate storage area, and some of your other ideas.

Sorry if I'm hijacking this thread. Bob

[Andrew Duncan]

A combination of under floor and overhead works for me in my shop.

There are two under floor runs. One run terminates in the middle of the floor with two outlets to serve the table saw and jointer/planer. The other run has three outlets on each of the two side walls for various other dust producers. I cap the perimeter runs that aren't used. This gives flexibility for placing tools like drill press, band saw, belt sander, etc. but does require that the table saw and jointer/planer stay put.

The overhead run is right down the middle with a drop over the workbench for bench top tools and another drop over the table saw for the shark guard.

The DC is in a separate closet with an outside door for access and the exhaust blows out a 10 foot overhead pipe to the adjacent woods.