Hi All,
My current shop has an unsealed concrete floor in a well insulated room in Central Texas–the temperature never drops below 50 degrees F. in the shop. I’d like to lay 3/4″ sheets of fir plywood directly over the concrete to make it less damaging to dropped tools and to my back. The cement floor always remains dry My question is, has anyone done this? How did it work out? I don’t want to build a subfloor if I don’t have to do that. I would appreciate your experiences with this. Thank you,
BruceR
Replies
Even with your dry floor, I'd lay down a grid of pressure treated 2x4's over some poly sheeting and nail the plywood to the 2x4 frame. If you are short on ceiling height, you can lay the 2x4's flat. The advantage to this is that you really won't have to worry about the moisture issue at all, it's not a huge amount of extra work, you won;t have to worry about your plywood sheet warping over time, and the floor will be even kinder to your feet and back. I don't think a sheet of plywood directly on the floor will provide much cushioning for your feet and back.
Bruce,
look into a product called Delta flooring. Its a dimpled plastic extrusion made for exactly what you want. It comes in 4x8 sheets or rolls of I think 100 feet by 5 ft wide.
I used it, then covered with 3/4 T&G product called advantex, in my basement here in RI. It raised the floor height by another 1/2, but the trade off is well worth it.
Its raised the temp in the basement another 2-3 degrees, and also acts as a moisture barrier. Half my basement is finished and half is my shop. It keeps the floor warm for the kids, absorbs noise, very very nice to work on in my shop, and handles the mobile machine wheels no problem.
No I dont work for delta flooring, I'm in the auto business.
Joe P
This is a video by a guy in town that writes a syndicated newspaper column. http://www.youtube.com/watch?v=JqK1DyKfB0Q
Thank you joepez, wilburpan and byhammerandhand--I'm now convinced there are better alternatives to just laying sheets of plywood on the concrete. The YouTube video shows an interesting t&g OSB product that can be laid in squares directly on the concrete. The Delta firm offers Delta-FL, which would work well, never warp, and keep out moisture, something the plywood alone wouldn't do. I'm not sure exactly which path to follow now, but it won't be the one I originally thought. Thanks to all of you for your help.
Best,
BruceR
Bruce,
I just completed a shop in south-central Texas (San Antonio) built on a slab. I laid a grid of 2X4 on their sides on 16" centers and then laid 3/4 plywood on top of that. Easier on the back and I was able to run power to islands where the major tools will be located. I topped the plywood with Armstrong linoleum tiles. Looks good but I am having trouble with the edges of tiles curling up in a few places. Going to try hitting them with a heat gun and pressure roller.
Good luck, George
You don't stop laughing because you grow old. You grow old because you stop laughing. - Michael Pritchard
Is 16" on center with 3/4 ply enough to handle heavy tools (Table saw, Jointer, etc.). I have been considering this for my workshop in my garage but I also have to deal with an unleveled floor and moisture.Thanks
DeGauss
DeGauss
I actually used a 16" grid. I used a ramset to nail the sleepers to the slab. Then used liquid nails to put down the cross pieces. Haven't seen any sign of problems with heavy equipment. The heaviest I have at the moment is a Grizzley GO586 jointer. I have it on a mobile base so the weight is all on 4 points. I am expecting a SawStop soon which will be a little heavier but I don't anticipate any problems.
Good Luck, GeorgeYou don't stop laughing because you grow old. You grow old because you stop laughing. - Michael Pritchard<!----><!----><!---->
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Actually, if you are using 2x4 PT for sleepers, 16" centers will give you 12 1/2" spacing between sleepers (assuming that the sleepers are laid on the flat) which will give you a floor that is a lot stronger than you think -- especially, if 1 1/2" rigid foam board is installed between the sleepers. This is exactly the floor I laid down in my shop, and I've had no problems whatever. I have a 470lb tablesaw and 460lb bandsaw sitting on it with no sag or give in the floor.
My shop has concrete floors. 7 years ago, I laid T&G Blandex on top of it. Blandex is one brand of exterior (waterproof?) waferboard used in subflooring. I have had no warping and no moisture problems.
Keeps the cost minimal. It works!
Hi 81treehouse,
Thank you for your help with this. I found a Blandex supplier not far from me and will go look at this stuff. Have you had any problems with outgassing? I was in a room years ago that was paneled with a similar looking product (chipboard), and the formaldehyde smell was absolutely overpowering. Is that still a problem?
Best,
BruceR
Zero outgassing as far as I can tell. This material is used as subflooring in houses and therefore outgassing would be mostly unacceptable.
Edit: No warping, laid flat with no sleepers, no plastic, no glue, nothing. Live on lake and no moisture problems but do run a dehumidifier year round. Also heat with propane unvented. Location is north central Arkansas. Easy on feet, tools not damaged when dropped, and cost is affordable and installation is easy (except for moving stationary equipment around.
A bad day woodworking is better than a good day working -- yes, I'm retired!
Edited 3/13/2007 12:13 am by 81treehouse
Hi 81treehouse, If this stuff can survive what you've thrown at it, it sounds like ideal flooring material for a workshop to me. Thanks 81, BruceR
BruceR
Hope it works as well for you as it has for me. One drawback -- when you drop a small screw, washer, etc, it is harder than heck to find. Especially with my old eyes!
LOL
A bad day woodworking is better than a good day working -- yes, I'm retired!
Hi 81,
I'm laughing because I evidently have the same problem you do. My three-year-old grandson runs around the shop picking up nuts, bolts, washers and other small stuff off the floor asking, "Why didn't you want this...or this...or this?"
Once that stuff drops below my knees, it's gone, especially if it's concrete color.
Best,
BruceR
Bruce,
My floor is T&G Blandex. Sorta like OSB so it is wood colored. The bad thing is I usually can't even hear (!) whatever hits the floor. Before when it was just concrete, at least I could hear it hit and have an idea where it might have bounced. Oh well, being a senior with poor eyesight is better than the alternative. <grin>
A bad day woodworking is better than a good day working -- yes, I'm retired!
Floated a 3/4" T&G plywood over a 1" Styrofoam isolation barrier over a barn floor (36' x 48') two years ago. Glued and taped the foam sheets together. Glued the tongues together and biscuited the ends to keep them aligned. It works well. If you are worried about load bearing, you can get high-density foam. Everyone thought that I was crazy.
Dear Bruce,
There is also a product called Dri-Core. It is available at the borg only here in CT. It is similar to the suggestion of the "Delta" flooring, in that, it is 2' x 2' squares of OSB with the dimpled material already applied. It is a pretty easy install, but the major downside is that I have only seen it at HD.
http://www.dricore.com/en/eIndex.aspx
Best,
John
Hi John,
Thank you. On the link you supplied is a locator link that indicates Dri-Core is available at the Borg near me in Central Texas. I'll call in the morning to confirm that and check it out. This likely would be the easiest flooring job of all.
Best,
Bruce
BruceR,
FWW did an article a couple of years ago and voted Dri-core the best...price/quality.
I bought a few squares (put in front of workbench and lathe) and have been testing it out for the past two winters, terriffic. Huge difference on shins and on cold transmission up the legs. Also, its kinda nice having wood under foot.
I would say that you do need a vapor barrier even though your floor is dry. Fine Homebuilding had an article about finishing out a basement including a floor treatment such as you have in mind. I don't have the issue, but it was within the last 3 years, I believe.
Cadiddlehopper
Similar to others, but I used PT 3/4 ply as sleepers with 3/4" foam in between. All my stuff is on wheels, and it rolls around just fine. More comfortable on legs and feet, a bit warmer, and no more 'OH ....' when I drop something (other than a bucket of paint, LOL.
Ed, you used pt 3/4 sleepers and then screwed plywood down. Did the sleepers hold the plywood well?
I am just getting ready to plywood my floor in the shop.I was going to rip 5/4 pt decking for sleepers and then use 1'' thick foam in between,but I was worried about moisture rotting my plywood, What do you think?
-Lou
Well I coulda done a better job, LOL.
I used 1.25" (IIRC) deck screws to fasten the T&G ply to the 3/4" pt ply sleepers, and that seems to be holding just fine. I did not, as has been suggested, use biscuits or, for that matter, anything to hold the 4' dimension of the ply together, but they, and the sleepers, are 'staggered' of course.
I could have improved things by attempting to shim the sleepers to compensate for the unruly basement slab (about the worst I've ever seen with respect to flat), but it's a huge improvement over what greeted me before.
Our basement is very dry, we sit on nice gravel, well above the water table, so I'm not concerned about rot. (crossing my fingers)
Ed, You think it would be a good idea to glue the sleepers down? Also, did you run the sleepers parallel to the eight ft side of the plywood or perpendicular. I don't understand using biscuits if the butt seam breaks on a sleeper.
Thanks, Lou
Mmmmm, how does one answer a question when one's work is, um, casual, yes, that will do, casual.
Our basement floor could be compared to the North Atlantic in January. To call it 'uneven' would be a complement. I should have used adhesive to stick the sleepers down (shimming the low spots, etc, etc) but I didn't. It does move a bit, but it is such an improvement. All my tools now sit flat, don't rock, and move easily on mobile bases. This includes less stable tools like bandsaw and drillpress.
Because of circumstances, and the fact that I'm inheritantly lazy, some of the ply runs 8' side to sleepers, and some runs 4' side to sleepers. I don't see any difference.
The 3/4 sleepers are 4" wide, 2' on center (IIRC). I used 3/4 T&G foam insulating panels between the sleepers with the T&Gs trimmed off.
YMMV
Bruce, Lou,
On a concrete slab, lay down 6 mil poly film, overlapping 6" with each sheet. Lay sleepers 16" on center (can be nailed with special gun if desired). Place two layers of 3/4" solid foam insulation between, gives 1 1/2" to match height of sleepers.
If you run everything 16" on center, it shouldn't matter which way you run the sleepers vs the plywood. Also, make sure that you stagger the seams of the sheets.
Solid Wood Flooring: Before installing the finish floor, we laid 15 lb. felt to smooth out any minor differences between the sheets of plywood. Also, there are usually stripes on 16" centers that makes nailing solid wood flooring easier, assuming the stripes line up with the sleepers.
Hopefully there won't be any issues with respect to transitions between your woodshop floor and any adjacent rooms which will need to be dealt with.
We even had a requirement to install the sleepers diagonally to the plywood subfloor! Yea, you guessed, government building!
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 3/20/2007 2:36 pm ET by KiddervilleAcres
Edited 3/20/2007 2:53 pm ET by KiddervilleAcres
Edited 3/20/2007 2:54 pm ET by KiddervilleAcres
Bruce, The delta fl system is a good system. it comes in 5ft rolls, roll it down and then screw plywood down to concrete. Make sure you use tongue and groove plywood and if you can, biscuit the ends. Also the floor will give a little so keep that in mind when working on your work bench. I used this system on some finished basements and have had some great results.
Hope this helps, Lou
Hi All,
Thank you all for your help with ideas for dealing with a concrete shop floor. I'm off this week to check out Dri-Core and Blandex, among other products you mentioned. I also will look into plywood on 2 x 4s and over foam. I never realized there were so many inventive folks out there; it seems that somebody has tried absolutely everything at least once! Thanks again.
Best,
BruceR
Bruce,
I can second the recommendation for Dri-Core. I put it down in my basement and am very happy with the result. I never had any water either but feel a lot better knowing the system could take it if I got any. It certainly makes the floor more compliant and warm and you loose less height than most any other option.
Do be careful to follow the instructions regarding installation, specifically offsetting the joints so that you do not have four corners coming together in one spot. I installed the majority of the floor but ran about 10 tiles short. The framers put the last few squares down and they failed to lay them properly in one spot. There is now a small bit of bounce detectible in that one spot now but nowhere else in the 20x60 basement.
Good luck.
Chris
Have you considered anti-fatigue floor mats ? I use these 2' x 2' interlocking foam mats that I purchased from Pep Boys. A pack of six cost about $10 - $12. I have them located in front of stationary tools and work bench. You can just use these where you need and do not have to cover the entire floor. Now I do not roll any machines around, so this would probably be a problem if that is how you work.
Rob
In another life I worked for a commercial hardwood flooring company bidding contracts for installation of wood flooring in commercial environments across the U.S. We followed NOFMA specifications, http://www.nofma.org.
If you go to their WEBsite, select Publications on the menu bar and you can then search their documents, .PDF format for Adobe Reader, et. al. Do a search for subfloor and it will point you to publications that cover both concrete slab installation and wood nail down installation, each of which are significantly dofferent. Most publications are downloadable for free.
If you prepare the subfloor per their instructions you will be able to lay virtually any finish flooring material you desire, or you can just stay with the plywood subfloor.
Perhaps the most compelling reason to follow these instructions might be with regard to flooring warrantees!
Hope this helps,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Hi Bob,
I replied to your thorough e-mail answer on wood floor info earlier, but it appears that it didn't make it onto the board. Thank you for pointing me to the trade association website http://www.nofma.org.
This tells what you need to know about all kinds of wood floors over all kinds of surfaces. There are excellent tech pamphlets for sale that have helpful line drawings. Best of all, if you don't want to buy the pamphlets, you can just download them free with Acrobat. Great site. Thank you for the assist.
Best,
BruceR
Hi Bruce,
Just trying to be like everyone else in here, helpful you know. Ever need anything, give a holler!
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Hi rpholland,
Yes, I have considered anti-fatigue mats, and I may use some in parts of the shop that don't get other floor treatment over the concrete. But I have learned my lesson about floor mats with holes in them. I used to have a dozen or so of the 4' x 4' mats with one-inch holes from the big box stores. I kept having to pull them up (heavy), because planer shavings and sawdust piled up under them in places the vac couldn't get to. I took them all out. I know to use solid mats for this in a woodshop from now on. Thank you for your reminder about anti-fatigue mats.
Best,
BruceR
Rob,
I use the same mats. Due to the size of my "shop", everything is on rollers and it works OK. Now, I don't have a Unisaw or anything near that big - that would be a problem I suspect.
Bob
Bruce,
Even if your slab floor is dry, concrete is a porous material and it will wick moisture from the ground. Most concrete slabs that are done right are poured over a well compacted gravel base overlaid with 6mil poly -- this provides somewhat of a moisture barrier but it is not perfect. For an unfinished slab there are several sealers that can be applied to prevent water from wicking through to the top surface of the slab.
Depending on how much you care to spend, I'd recommend you completely cover the floor with a waterproof membrane such as Grace Ice & Water Shield, or Grace Bituthene overlapping the seams by 6". You can then overlay your sleepers (whatever you use 2x or 5/4 make sure it is PT) 16" on center. Since your climate is relatively warm, you don't need to insulate your floor, but rigid foam between the sleepers will give you a stiffer floor. Covered with 6mil poly, overlapping the seams 6" and sealed with duct taped, you will have a dry floor! As to sheathing, I recommend Advantech over standard 3/4 ply because it is moisture resistant, (it will not swell when exposed to moisture unlike plywood or OSB subfloor materials) plus it is stiffer than plywood and has greater shear strength. It cost a couple bucks more per sheet but is a worthy investment in a floor you intend to last a lifetime.
I did a lot of research before I installed exactly this flooring system in my shop, conferred with a couple of contractors I know and a friend that is an engineer. This is exactly the type of floor system they recommended for a bare concrete slab.
Good Luck,
Michael
Hi pzaxtl,
Thank you for this complete explanation. I've not heard of some of these products before. I especially want to check out the Advantech you recommend.
Best,
BruceR
Hi Bruce,
I have done two shops here in CO , that I layed 3/4" ply over concrete. I used black plastic with tar paper over it and have had no problems with the floors at all. Sure has saved lots of nicked and dinged pieces over the last 10 yrs.
Woodman
So, hey guys how did the floor work out?
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Hi Bob,
I'm still checking out possibilities that were suggested by folks here @ Knots. I got lots of good advice, and there's lots I didn't know.
Best,
BruceR
I'm considering doing something like this as well except I want to be able to run DC ductwork underneath. Anyone see any issues with using 2x6s on edge as the subfloor? My ceilings are 10' so I can probably afford to lose a few extra inches.
Hi Bonecrusher,
I don't know why you couldn't use 2 x 6s on edge if you can spare the loss of headroom. I got some really helpful answers in this thread in answer to my original question. Especially good were the reminders about treating the slab so it'd be moisture tight.
Best,
Bruce
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