I have a 30x50 detached garage and a lot of moisture seems to be coming up through the floor. I don't have any water drainage issues on my property and the floor in my attached garage is fine and only about 25' away. The builder claims to have used a vapor barrier before pouring the floor but I'm sure about that now:( Question is, is there anything I can do about it? Epoxy paint is expensive but if it will seal I will try it. It is not heated full time either, just has a fire place for heat when needed. I store both chevelles in there and notice surface rust forming on the brake rotors. If I move something that has sitting on the floor for more than a day or so, there is a small amount of water underneath it! What should I try?

One of the BETTER floor systems. It will fix the problem, I know.:yes:

Other than heating the place all winter, your best hope is running a dehumidifier all the time. I'm not sure but I think dehumidifiers need warm air to be effective. Epoxy paint won't seal out the moisture by itself, but it will certainly help. It also makes spills a lot easier to clean up. One other possible remedy is to cut about an 18" square hole in your slab to create a sump and install a pump in it to remove accumulated water.

A simple fan running can help with this problem. If your only heating it when you need it, you have to keep a consistant warm temp in the winter or moisture will be a big problem. I was going to do that and gave up on the idea, my garage is not insulated.

You might need to get some air going through it. You said you heat it on occasion, but you didn't say if it was insulated.

Maybe if you put some vents in it when you aren't heating it.

On page 3 and 4 of this http://www.1969supersport.com/paintroom.html you will see a couple of insulated vents, something that you can close up and keep the heat in when you want to.

Not necessasarily like the ones I made, but some type of venting system.

I have a detached 30' x 50' garage with a concrete floor, with no insulation, I never heat it, but it has vented eaves and a ventilated roof peak the full length, it stays dry in there year round, I have sand in a bead blaster that sets in there all the time, never a drop of moisture.

I live a couple of blocks from Lake michigan and it gets damp a lot from the lake.

My garge is always dry, you could put your hand on the floor and its just dust year round.

Once you get air going through it, it will dry up. I have four skylights also which bring in sunlight which might be helping out also, but I think just air will do it.

The one on the left, http://www.1969supersport.com/robsgarage.html it only has skylights on the side were looking at.

The one on the right is heated and super insulated, it stays dry year round, but I keep the vents closed when I'm not in there.

I can sand blast something and let it lay around for weeks if i want to and it won't rust.

So I guess in my case, insulation on one and lots of vents on the other. It seems like a lot of the year I could walk out in my yard at night and my shoes would be soaked right away, so we definitely have some moisture around here.

The last picture if you look at the outside versus the inside concrete you will see how lighter colored it has stayed in the vented garage, and the concrete outside will be wet a lot.

Thanks for the replys, it is a finished garage with insulation and sheet rock, textured and painted with two sky lights and insulated doors. One thing I don't have is ventilation, I'll be looking into doing something about that soon.

I was just thinking a little more about this.

If you put a fairly large vent on the two gable ends, large ones as high up into the peak as you could, and make it with some type of a latch you could reach up with a pole of some sort to open and close them, like one of those long handled roof snow scrapers you can get at a building supply, the poles are fairly rigid and super light.

I would imagine once you get air going through the upper part of your garage it would draw the moisture out of the concrete.

What you probably have is moisture condensing out of the air onto the cold concrete rather than coming up from the ground.

I have this unit in my basement...it may be something for you to consider.

http://www.humidexatlantic.com/content/humidex-solution/

What you probably have is moisture condensing out of the air onto the cold concrete rather than coming up from the ground.

:yes:

Simple ventilation to let the humidity out will probably take care of the problem.
Otherwise keeping the concrete warmer then the air is the only answer.
Humidity will condense on any surface that is cooler than the air.

Two words as always..

Car jacket!! :)

Other than heating the place all winter, your best hope is running a dehumidifier all the time. I'm not sure but I think dehumidifiers need warm air to be effective. Epoxy paint won't seal out the moisture by itself, but it will certainly help. It also makes spills a lot easier to clean up. One other possible remedy is to cut about an 18" square hole in your slab to create a sump and install a pump in it to remove accumulated water.


Some dehumidifiers can work in temps to as low 40*-45*.

Respectfully,
John R.

Mike,,,invest in a dehumidifier. There are plenty out there that are functional to 40' or even lower. Even in the dead of winter, I still pull gallons of water from my basement that leaches up from the slab. A typical dehumidifier will freeze up...it must be designed to work at low temps for your garage... about $250

Just for kicks, try to duct tape a 18"18" piece of plastic sheeting to the floor, leave it there for 24 hours, then peel it up.. If it's dry, it's coming from the air in the building, if it's wet underneath, it's coming from the slab..

You can also borrow or buy a moisture meter, but this is a simple cheap test...

Just for kicks, try to duct tape a 18"18" piece of plastic sheeting to the floor, leave it there for 24 hours, then peel it up.. If it's dry, it's coming from the air in the building, if it's wet underneath, it's coming from the slab..

You can also borrow or buy a moisture meter, but this is a simple cheap test...

That would work providing the concrete was 100% vapor proofed by the duct tape, otherwise no.

Humidity WILL get in to any colder dryer area through any hole it can find because it's always trying to migrate to the cooler-dryer areas.

I have the same problem and starting to grow mold on my walls. I've done alot of searching on the net and decided to go this route after removing the mold. http://www.radonseal.com/catalog.htm

I will bet even money that you can do all above and the brake rotors will still get surface rust on them. They would need to be in a NASA controlled envirement to stop it. Bare metal with no protection will always rust. You could pump a inert gas and remove the oxygen and stop it. But if you got 2 million dollars just get someone to polish them daily for less money.:D

I should mention that it dose not have valted ceilings, two bays are 10' ceiling and the other 16'. Two others are open. There is a crawl space above the trusses but is full of insulation. The only thing that bothers me about ventilation is drawing the cold air through the building during the winter. I don't have natural gas out here, my other choice would be Propane. I have been looking for a way around it though so I wouldn't have to look at the tank. I figure sealing the floor and heating to 60* year around should help, maybe a ceiling fan or two?
http://i67.photobucket.com/albums/h293/66ssfan/House001.jpg
http://i67.photobucket.com/albums/h293/66ssfan/70chevelle005-3.jpg

That would work providing the concrete was 100% vapor proofed by the duct tape, otherwise no.

Humidity WILL get in to any colder dryer area through any hole it can find because it's always trying to migrate to the cooler-dryer areas.

Trust me here, if there is moisture coming up from the slab, this will show it, the concrete will be WET under the plastic and there will also be condensation under the plastic itself... We use this meathod ALL THE TIME to test slabs for moisture before installing flooring, I'm not just making this stuff up..

I will bet even money that you can do all above and the brake rotors will still get surface rust on them. They would need to be in a NASA controlled envirement to stop it. Bare metal with no protection will always rust. You could pump a inert gas and remove the oxygen and stop it. But if you got 2 million dollars just get someone to polish them daily for less money.:D

Careful with that bet ;)

I have always used a CAR JACKET.. my car has been in heated garage, air condition garage, Non heat, cold cement one car garage with water puddling in after any storm, and all things in between over the years... No LIE! I have many Unpainted Bare Steel parts and not clear coated either.. ie., my driveshaft is bare steel! BUT... my car is always inside car jacket.. NEVER.. not once.. have I had flash rust on any parts!! drums, exhaust manifolds, driveshaft, suspension components... :noway:

Do yourself a favor my friend.. invest in a Car Jacket.. do a Search.. about $275.00 I think.. maybe less.. best money you will spend and less then what you will spend to do many of the other things that may still not solve your problem.

MC

Trust me here, if there is moisture coming up from the slab, this will show it, the concrete will be WET under the plastic and there will also be condensation under the plastic itself... We use this meathod ALL THE TIME to test slabs for moisture before installing flooring, I'm not just making this stuff up..

If I move anything sitting on the floor there is water under it. I have large drip pan under the '70 and there is a lot of water under it every time I move it. You can see the floor is darker in color when its damp and lighter when dry.

I'll look into the the car jacket Mike, it seems to be hard to beat for the price:)

Trust me here, if there is moisture coming up from the slab, this will show it, the concrete will be WET under the plastic and there will also be condensation under the plastic itself... We use this meathod ALL THE TIME to test slabs for moisture before installing flooring, I'm not just making this stuff up..
I trust you, I said it WOULD WORK ..providing

I did not read all the post but when you get the dehumidifier get one that you can hook a drain line too and run through the wall to the outside or you will be dumping the tank daily. When the tank is full the unit will shut off. My neighbor has your same problem in his finished basement and the unit worked well besure and get one big enough for your square footage. If you are getting that much water and if not stopped you will get mold on your sheetrock walls which we all know is bad. OOPS! re-phrase mold like substance. No such word in the construction buisness as mold!!!

Careful with that bet ;)

I have always used a CAR JACKET.. my car has been in heated garage, air condition garage, Non heat, cold cement one car garage with water puddling in after any storm, and all things in between over the years... No LIE! I have many Unpainted Bare Steel parts and not clear coated either.. ie., my driveshaft is bare steel! BUT... my car is always inside car jacket.. NEVER.. not once.. have I had flash rust on any parts!! drums, exhaust manifolds, driveshaft, suspension components... :noway:

Do yourself a favor my friend.. invest in a Car Jacket.. do a Search.. about $275.00 I think.. maybe less.. best money you will spend and less then what you will spend to do many of the other things that may still not solve your problem.

MC


I still fell good about my bet. Just because you can't see it don't think its not rusting. Irons natural tendency is to return to from where it came. Nothing will stop rust but there are several things that will slow it down like paint and oil and a controlled atmosphere. The old saying that Dr. rust never sleeps is true.:yes: If you can't see it now give it some time. You will. I'm not saying that your car jacket won't help and slow it down but it won't completely stop it. It sounds like you never drive your car since you have no rust on the exhaust manifolds. If you apply heat and outside air from driving, brakes and exhaust will rust and will if you don't drive it, just not as fast. Thats not my opion its just a physical property of iron.

Since your only heating it up when you need it. Thats part of your problem right there, The change in temps help make condensation. A humidifier will help but only when its warm, they dont work when its below freezing otherwise they will freeze.

I put one of these in my basement - it can handle a 2500 sq ft area, its more efficient than the portable ones you find at HD and works great. A little pricey, but our basement feels like a 'normal' part of the house - not a damp dungeon.

http://www.thermastor.com/Santa-Fe/