Storing A Car On Garage Concrete Floors

[TallCool1]

Have been storing my old car for years in a building that has a wooden floor. I've liked this place because the wood pretty much takes care of any moisture issues, and my cars have never developed rust while stored here. But my buddy just built a huge garage on his property and has offered to let me put my car there. His garage floor is concrete. Do you guys have any tips for dealing with the moisture when leaving a vehicle parked on concrete for long periods of time?

[ws6transam]

I would suggest that you consider keeping an air gap between your tires and the concrete via four jackstands, or else four caster assemblies. Other than that, I don't see much difference in moisture content of wood versus concrete. I've been storing on concrete for seventeen years and haven't seen much problem in terms of rust.

[FIREBALL 440]

Concrete should have less moisture than wood I would think.

[Do the Doo]

Concrete should have less moisture than wood I would think.[/b]

not true, depends on the grounds underneath and how it was installed. My shed is 12"+ off the ground where my sleds are is never wet, but my garage is always moist after a heavy rain fall.

[TommyBoy68]

I put my cars up on 4 jackstands, and roll out some poly underneath. The stuff you can buy in a roll at home supply stores like Menards, etc.

I noticed a fair amount of rusting the first year my car sat on the concrete slab all year-round. That motivated me to do something to try and combat the moisture. I could see traces of rust on the concrete following the driveshaft and exhaust system. The poly shows evidence of moisture quite often on the underside, but I have not had the car down, nor have I crawled under there, to see how well it's working.

Concrete is not usually a good surface for storing, but often you don't have options.

[Thumbdoctor]

Jim,

The best way to determine the amount of moisture the cement floor holds is to duct tape a 12" X 12" piece of clear plastic (poly urethane bag will do) to the floor where your going to park your car. Let the patch sit for 24 hours and look for mist or water droplets under it. If the plastic is dry no problem. If not consider a sheet of 6 mill heavy duty poly to place before you park the car. Another great trick is to get some Silica Gel and pour it into socks then place one in the back of each wheel to control humidity (keeps the brakes rust free). BTW, Silica Gel is what's in those packages you find packed with electronic appliances. Its available at most hobby stores for drying flowers. Rice will do in a pinch but doesn't endure as long as Silica Gel. Put a few inside the car with the Arm & Hammer baking soda to control odors. Spray all fasteners with Crown metal preservative and you'll be good to go.

[michahicks]

Jim, from lessons learned in aircraft hanger. Anytime there is a major change in air temp outside the garage/hanger, seems like something is going to sweat. The cool floor attracts a ton of moisture on warm moist days (ever notice it changing to a darker color?), as will the metal of your car. One day in the early spring we had a fairly warm day after some really cold weather. I went into the hanger and was horrified when I just happened to glance inside the plane and saw condensation/water droplets literally running down the face of the intrument panel! Thousands of dollars in sensitive electronic and gyro equipment! Decided then it was time to take action. After a lot of checking with the guys in similar circumstances, I went with 2 large commercial ceiling fans. Ran them on low 24/7. Never had another issue.

If the ceiling fans aren't practical in your situation, betting anything to help the air to circulate in the garage would be worth the trouble in preserving that expensive metal..... FWIW

[TallCool1]

Anytime there is a major change in air temp outside the garage/hanger, seems like something is going to sweat.[/b]

That's why I brought this up. And that's why for the past 20 years I've been storing my cars in this nice cinder block building with a wooden floor. I've never had an issue with condensation in this place. I'm paying each month to keep them there, and my buddy is offering me his place for free. I'm surprised more people don't realize the damage that can be done by storing something on concrete. If it was my garage, I would leave some kind of fan on to circulate the air.

TD, I thought about those silca gel packets. They are used in many items. Don't know where I could get enough of them to lay in and around a car though.

I may just leave the car where it is 'til Spring, then bring it home where I can take care of it.

[94ZR580]

If subsoil moisture is migrating through the concrete, then it is migrating through the wood too. if a proper vapour retarder was used under the concrete slab then there should be no migration of subsoil moisture. If there is an air space under the wood, then there will be some air circulation that will help mitigate the moisture. Moisture from the air condensing on a cold surface is another thing which is influenced by relative humidity and can be alleviated by ventilation, or air circulation and it should much less of a problem in the winter time in northern climates. If a sheet of poly is all that it will take to save six months rent for the vehicle storage, then that sounds like the deal of the century. :thumbsup:

[skippyf15]

I put a small fan on the floor. just to move the air under mine. It kept the floor dry and the critters away also. I checked it weekly just to make sure and it didn't bother my electric bill either.