I’m planning a workshop addition to my garage.
16×20 woodworking area on the gable end with an 8×32 shed along the eave wall for storage and a bathroom.
My question is about the floor design.
16×20 is not a huge woodshop, so I plan to outfit it with combination machines
(saw/shaper and jointer/planer). These are very heavy. Is a wood floor over crawlspace practical, or am I better off with a concrete slab (using rubber mats for comfort under foot)? I’d like to be able to run DC ducts through a crawl, but am thinking a slab will be cheaper and stronger, with a smooth transition to the existing garage floor.
Replies
My shop is on a concrete slab. It is hard on the feet and cold in the winter which makes my feet, knees and back hurt if I am in the shop all day. I am considering adding a product called DriCore to my floor to improve comfort. Combo machines like to be away from the wall for access to all four sides. If I had to do it over again, I would go for the crawl space option to get power and dust collection connection hoses off the floor. Due to the weight of machinery, I would suggest having the floor designed by a structural engineer.
Steve
Check out a product that is simular to the plastic bottom on Dri Core but is comes in a roll for about $43.00 at Lowes. I looks good and has less seams to deal with. Sorry I do not remember the name of this product.A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing.
George Bernard Shaw
All these responses (thanks!) reinforce my belief in the value of a wood floor.
Nothing is built yet, so I can still do what I want. The question now is, is it advisable to build the wood floor over sleepers on a poured slab, or go ahead and build a conventional (but heavily reinforced) wood floor on joists over a crawl space? Sleepers on a slab sounds strong, but I don't like the idea of a rubber membrane over a moist slab of concrete. Where does the moisture go for the next 30 years or so? Does it just stay harmlessly in the concrete?
How much more expensive is the crawl (or cellar) option likely to be, and what measures will I need to take to support 1.5-2 ton machines on a 16x20 floor? Are I-joists good enough? Steel beams necessary?
tom
My shop is 36' X 45' with a concrete floor. I built it 3 years ago. One possible option for you is one that I chose for myself. I don't have combination machines, but I do have old american cast iron machines from the industrial age. Most are 2000 lbs. or more, and I need a forklift to move them. You should at least consider a wooden floor over sleepers for your bench and finishing areas, where you'll spend alot of time standing, and have the machine area be concrete, or wood floor over dricore. I just left my machine area concrete, and don't have to worry about whether or not the floor will withstand the combined weight of a machine AND the forklift to move it, a combined weight of over 10,000 lbs!
Jeff
tough question, my answer would depend on how cheaply you can ge the work associated with each option performed.
i think my preferance would be for the crawl space, you would then always have easy access to your electrical and dust colluction distribution. just to be on the safe side I would use 2x10 (or even 2x12) joists spanning the short direction of the shop and I would set them on a center 4x4 beam on 4x4 posts. this might be overkill, but you will be glad of it if you ever decide to move a great big combo machine into the center of your shop. I'd also put at least 6" of clean rock in your crawl space, It beats the hell out of crawling around in the mud. I'd use 3/4" t&g plywood (not osb) for your subfloor glued and screwed to the joists, you can then either use that as your finished floor or put down some other flooring material on top of it. remember to make the crawl deep enough to allow room for the joists ductwork piping and still have enough room for you to crawl below it...
Mum's neighbor sticks boats (like ~ 40' sloop, along with a couple of others) in his barn, which features a wood floor over a crawl space.
My 'shop' has 3/4 sleepers with foam insulation between and 3/4 subfloor on top. My choices were pretty limited as I wasn't about to dig out under the basement. I've done two floors like this, and they have worked out quite well. All my tools are on mobile bases (Unisaw, dp, bs, jointer) and don't appear to have caused any depressions in the floor.
In my "past life" I worked in a lot (over 20) of commercial stage scenery shops at one point or another. One of them had mechanicals (DC, Elec., air) running under the shop floor and it was by far the biggest pain in the a** system of any. It seemed like a really swell idea at first but the demands of that sort of shop are for maximum flexibility at minimum setup time. Having to pull up flooring to move any of those systems is time consuming and disruptive.
The best shops I worked in had all systems running overhead with lots of options - many 120v and 220v drops, air reels, and flexible, powerful DC systems. Now then, a scenery shop has similar but different requirements than a cabinet shop. Rarely do woodworkers need to assemble a 40'x30' stage! But flexibility is always desireable - I'd keep my systems overhead. One man's opinion.
One other possible consideration is resale value of your shop some day in the future. There are a lot more people out there who want mechanics shops than WW shops - a concrete floor with a wooden sleeper system again offers the most flexibility and most options for resale.
Redwood Curtain - I understand your concerns and with a sleeper system this would be a real PITA. However, if this were a crawl space type of system, you don't have to pull up flooring to change. I personally don't care for sleeper type systems but can understand that it may be the only option for some applications. I don't necessarily believe this to be the optimum choice for new construction.
You have a good point as to resale value. When I built my current house and shop, every choice I made was made on my perception of resale value. Based on those perceptions with respect to my woodshop, I built a detached 3 car garage because I assumed that it would enhance resale value greater than just a woodshop for most buyers. Up to the point I built the house, the longest time I spent in any one spot was 3-1/2 years. I have been in my current location and shop for over 16 years now and can honestly say that I regret every decision made that was based soley on my perception of resale value. The 3 car detached garage with concrete floors as a woodshop is the most prominent of those "mistakes". Hindsight is usually 20/20 or better and at least in my case, I wish I had chosen a different option for my woodshop. I think the ultimate choice of the "best" alternative is highly dependent on individual circumstances.
Steve
An easy solution is T&G Advantek. 4 x 8 sheet directly on the concrete! "Things" only need to be moved about 4 feet for each sheet. If selling, they can be simply lifted off the floor! I have had NO problems with my floot since doing this. Everything seems to hold the sheet tight to the floor so I have seen no warping or movement. Also, easier on the feet and dropped tools.
A bad day woodworking is better than a good day working -- yes, I'm retired!
I've used Advantech for subfloors, but never for a "finished" floor. How has yours held up -- i.e. abrasion, pushing things around, etc.?From what yous said, you did not attach it to the floor in any way, right? If it is not attached, do any of the sheets tend to curl?Did you surface seal it -- i.e. paint, poly, etc.? ********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Yes, it is made for subflooring but I used it for the main surface laid right on top of the concrete. It is tongue and groove construction so each piece interlocks. There are no glue or fasteners holding it flat. It has not curled anywhere but remember, each sheet usually has shelving, TS. BS, router table, etc sitting somewhere on it. I don't think there is a single sheet that is not weighed down in several places by something in the shop! (A shop is never big enough so you never have plenty of open room! <grin>)
I vacuum with a shop vac and some tools are on mobile bases and some aren't. Everything rolls fine. One of the better benefits is it is nice on the feet and on tools (chisels, etc) when they are dropped. The only problem I've had is when you drop a tiny nail, screw, router bearing, etc, they can be very hard to find! It is holding up terrifically but I would not run around barefoot. <grin>
I heat with a 5 brick propane infrared heater in the winter and run a dehumidifier 24/7 year round. Since the heater does not run but a couple hours several times a week, I have not worried about rust from the water vapor I am told propane heaters generate. The dehumidifier kicks off and on several times a day but only runs for about 10 minutes each time. By the way, I live on a 40,000 acre lake so we do have high humidity outside.
The concrete under the floor was cured for about a year before the floor was installed. And the dehumidifier ran for hours at a time originally. I think if I had used a plastic moisture barrier, it would just have allowed the moisture to build and I would be fighting it constantly. Since it was bone dry when the Advantek was laid, I have had NO moisture problems at all!!! No rust on anything!
Cheap, not bad looking, easy on feet and tools, and removable if I sell and someone wants the concrete floor back!
A bad day woodworking is better than a good day working -- yes, I'm retired!
Edited 12/9/2006 8:57 pm by 81treehouse
Advantech is a fabulous product: it is stiffer than plywood and has greater shear strength; it is also water resistant. A contractor friend of mine tossed an offcut onto his front lawn and left it there for a year, weathering rain and snow and sun. The product did not delaminate like a plywood would have done nor did it swell appreciably. That said it is not waterproof so you should install some kind of moisture barrier between the Advantech and the concrete slab. One nice feature is that it has the layout for nailing printed on the top -- both for 16in. centers and 19.2 in. centers, every 6 inches across the width. The manufacturer (Huber) stands behind the product with a 50 year warranty. I have several 500 lb. machines sitting on it and it performs marvelously.
I installed Advantech over sleepers and am quite satisfied with it. Obviously, it is not a finished flooring material but then again I installed it as a shop floor. I painted it with an epoxy paint to seal it against solvents and it looks and functions fine. Finally, I can roll my machinery around without contending with a very rough concrete surface which is what I had before, and my back and joints feel so much better after a full day in the shop.
Wood flooring is the way to go, You must use a vapor barrier. You can also build a wood floor over a concrete slab.
I am a hardwood flooring company owner. If you decide to use wood floors, take the proper precautioins against moisture from the concrete which will retain moisture up to 4 times as much as wood. We have had much success with a product called Bostiks best glue. Either build a "sleeper" system with 2x4s set in the glue laid flat, and then plywood laid normally as if over joists. You will either have to keep some kind of wieghts on the 2x4s to keep them flat, ram set them, or tap-con or concrete spikes, the latter two will require hammer drilling pilot holes. We have also had no problems with the plywood (3/4)laid straight into the glue(trowelled on) and then pilot holes for the concrete spike nails to be driven into. The Bostik is an excellent moisture barrier, and incredible glue, and the few jobs done this way are still fine ( one is my own basement, and I did the same for a friend). You will have to use shorter(1-1/2)hardwood cleats or staples or install luaun over the plywood if you use regular 3/4 hardwood (recommended). Don't cheese on the glue however. In 12 years of business I have never had a problem with this product ( and I don't own stock in the company). It is expensive, will get all over everything, and it is hard to remove without thier remover product, but it will work. I'm preparing to do this in my shop with a concrete floor early next year.
I have a converted 1 1/2 car garage as a shop -- which means that the floor is a concrete slab. Concrete is a great no fuss flooring option that will easily endure the abuse of a woodshop. However, concrete is also porous and it will forever wick moisture up from the ground. I thought of sealing it but unfortunately the previous HO that had the garage built was tighter than the bark on a tree and didn't want to bother with paying for a finished slab -- as rough as it is, I doubt it was even screeded! So, finally, after four years of a perpetually damp shop (and COLD in the winter when the temp drops to -32 and that damp concrete slab serves as a giant ice cube) I installed a wood floor using water proof membrane overlaid with 2x4 PT sleepers, 1 1/2 rigid foam, 6 mil poly and Advantech flooring. I wish I had done it four years ago. Go with a wood floor -- you wont regret it.
Tom,
My shop is in the cellar with a concrete floor.
While looking for windsheild wipers a few years ago at Pep Boys I found 1/2" 2' X 2' foam flooring dark grey. HD sells it in colors for kids play areas but very expensive.
I bought as much as Pep Boys had several times and buy it when I see it there. The difference is amazing. Comfortable to walk on and my feet don't get tired and my back doesn't hurt after a long day working.
ASK
Tom:
I favor the crawl space and wood floor. Many machines shops and steel mills all have wood floor (over concrete) - I would suggest both underlayment - 3/4 ply and 1 1/2" flooring like Doug Fir - conservative, but strong. And for flooring joists, recommend checking your area for sawmills - I found full 2" x 10" oak - green, of course - for less than HD's 2x in spf species.
Nailed the oak in green and allowed for a little movement - have had no problems and it's been in for 4 years. Oak will give you considerably better structural properties than lumber yard spf or Doug Fir. And because you don't have a large space, you can go really conservative with 12" centers.
This forum post is now archived. Commenting has been disabled