Storage Garage Floors (concrete vs. wood)

[Mark DeFloria]

A friend is in the process of constructing a garage to store antique vehicles. He had heard wood floors are preferable to concrete due to humidity. Is there a preference between a wood floors or concrete floors? The building will be well ventilated and not heated.

[palbuick]

I had a new garage built 4 1/2 years ago, and had contractor put vapor barrier down before concrete floor was poured. A heavy plastic was laid down and concrete 4" poures over it. I don't get any condensation at all, I can leave sandblasted parts sit for months and don't get rusty, as long as doors aren't opened when humid outside.<P>Jim Schilf / palbuick

[Guest BillP]

I agree with PalBuick. I have an old barn that I recently put a new foundation under (what a job!). In addition to 2 layers of heavy mil vinyl sheet as vapor barrier, I put 4' by 8' by 1 inch thick "blueboard" styrene foam sheets down as a thermal barrier. Then 6 inches of concrete reinforced with 4" square welded wire fabric (mesh). I saw cut the green concrete to avoid random cracks. <BR>As you can guess, I tend to overbuild things, but at least the next guy won't have to worry about it like I did. The barn and contents are dry. <BR>I would not build a wood floor barn.

[palbuick]

I wish I had put the styrene foam down. The floor gets awful cold here in Northern Ill.<BR>My floor is 30' X 80' and the cement masons <BR>made cuts in floor 10'squares. some light cracking but in the cuts only in 4 1/2 years.<P>Another Item, are you going to do any work in garage?<BR>I ran PVC plastic pipe around garage, for my air compressor, using 1 1/2 pipe. This was done after walls and roof were up, and no obstructions. Drop lines of 3/4 " at various points around garage,workbench, at doors for filling bike tires and lawnmower.<BR>a lot cheaper and less condensation than steel pipe.<P>Jim Schilf / palbuick

[ply33]

I have heard that using PVC for compressed air is a bad idea: The failure mode of the PVC is to shatter, so damage to a pressurized system will lead to flying shrapnel. Metal pipes will tear open rather than shatter so there is less danger on failure. In addition, you want to cool the air as much as possible so that the moisture condenses out. Metal pipe does a better job of this.<P>The professional designs I have seen call for a large diameter loop of pipe around the perimeter of the work area. By looping around the work area with large diameter pipe, the pressure losses are minimal no matter where you attach to and you can be running multiple air tools off different taps with little interference. The loop is tilted slightly so that any condensed water flows to a single low point. You put a drain cock there. The "drops" actually come off the top of the loop before making a "U" and coming down (so they don't get water dropping into them). And, of course, you put a water trap at the end of each drop.<P>This gives you a safe system that provides dry air.

[Guest Hal Davis (MODEL A HAL)]

I'll second that, Tod. I have recently done my air lines similar to this. Moisture separators will not separate moisture while still in vapor form. It has to be condensed before going to the separator. If not, it will pass right through and condense the instant the pressure decreases, like in your air ratchet, or worse, just outside your paint gun nozzle.

[Guest]

A vapor barrier under a reinforced concrete floor is absolutely the way to go. Further, if the shop is heated, heaving and cracking is far less likely to happen whether or not the floor is scored. I didn't score mine, but I did put in the vapor barrier and reinforcement. The shop is heated by a temporary system using a single kerosene heater set constantly at the lowest setting and it stays at 65 deg.F. except when the outside temp drops below 20; then it drops to about 61-62. The shop is 30 by 40 with a 10 foot ceiling.<P>Other major factors in the protection of the floor are having the roof properly drained using good gutters kept clean, and proper grading of the area around the building. This will help prevent excess water from collecting under the floor which is the single biggest factor in heaving and cracking in the freezing weather.

[Guest BillP]

The 'scoring' or saw-cutting is not done to prevent or reduce the possibility of the concrete cracking. A concrete pad will crack<BR>under most conditions, whether it is reinforced, has a properly prepared sub-base, has curing compound applied, etc., or not. The saw cutting is done to control or guide the crack so that it is not random in its appearance or location on the pad. If you look carefully in the kerf of a sawn pad, you'll usually see the crack. Bill

[Guest SalG (Sal Grenci)]

Try contacting Brooke Davis of the Hornet's Nest Region, he designs garages.SalG<BR>bdavis20@carolina.rr.com

[ronbarn]

I would advise against the wood floor. They are more difficult to maintain and keep clean, plus after you have spilled oil and other flammables on them for a few years, they are a real fire hazard. Properly designed and constructed, concrete is the only way to go. Also think about the texture. Very smooth can get slippery when wet, but it makes cleaning up a lot easier.<P>As for PVC air lines - I used the design hints right out of the TIPP catalog with tilts, take offs, drains and all. The only deviation was that I used PVC. The PVC has a pressure rating at 600 psi (with of course the manufacturers margin of safety) and I charge my lines at max 175 psi. Been working good for over 12 years. As for problems at the end of a paint gun, have switched to HVLP with separate turbine compressor. <p>[This message has been edited by ronbarn (edited 03-15-2001).]

[Guest rcirilli]

I built my pole building six years ago. I had a six inch base of river rock put down then six inches of concrete with fiberglass reinforcement. They concrete has four expansion joints. The building is 32 X 40 X 10. To date I don't have any cracks, it's unheated but very dry year round. It is well vented and well insulated. The river rock being round, holds air and acts as a barrier, so I was told. At any rate it's been great. I also vote for concrete. Wood requires too much maintenence and could be slippery.

[ply33]

Ron,<P>The issue with PVC air lines is not with the pressure rating but with the failure mode. When something flys off the drill press, grinder, etc. and strikes a pressurized line what happens? For metal tubing you get a dent or a leak depending. For PVC you can get an explosive failure.<P>PVC is okay for non-compressible fluids (e.g. water).<P>Basically you look at how much change in volume of the container is required to release the pressure. For compressed air you need a lot of volume change before the driving pressure drops to zero (lots of stored energy to get rid of). For a non-compressible fluid the volume change needed to release the pressure is very, very small (very little stored energy to get rid of).<P>This is the same reason that pressure vessels are "hydro tested": When you fear that a pressure test failure is possible, you pressure test with a substance that limits the failure mode to something safe.<P>You also look at how the material will fail: Will it split open along a seam (typical metal tubing) or will it fracture into lots of small pieces (typical PVC tubing).<P>Yes your PVC tubing works right now. And it could work fine for decades to come. Just hope some external damage does not occur to it when you have it pressurized, because you don't want to be around it when it happens.

[ronbarn]

Tod, understand your comments. That's why I reduce the pressure in the lines to zero when I am operating machinery that could cause the type of damage you mention. The lines are located in places and protected to prevent external damage. Good comments. Ron

[jaxops]

Nobody asked me but...as an alternative:<BR>I use my regular garage with a concrete floor, and found that in the summer (in Virginia Beach) the humidity in the garage was overwhelming, besides eliminating the reason for putting an antique car in there. I bought a dehumidifier from LOWES and it has made a significant difference. I know that I have a lot of air leaks, etc in the doors, but this really works. I ran the drain hose out of the front and into the bushes.<P>------------------<BR>

[Al Smeraldo]

If you really want to do it right. Before pouring the concrete put pipe in the floor for radiant heating.