What are the best ways of keeping the garage dry. Thanx

 

What kind of moisture problem are you having, please explain...

 

I may have a similar problem. My uninsulated, detached garage has condensation problems on the cement floor when it's even just a little humid out. I suspect the problem is lack of ventilation and plan on installing gable vents if I can ever get off my lazy backside. Is that the kind of moisture you're talking about?

 

I am having it condense on the floor and stuff. the air is also pretty muggy inside. thanx

 

Yes, ventilation is the key. Put in one of those turbine vents in the roof. Put a damper in under it so you can shut it off if you are heating your garage.

 

I had a similar problem in the little yard shed we put up 2 years ago. In the spring when I went in to get things out they were all rusty. Cut in a gable vent this past summer and that solved the problem. In the attached garage I have a ceiling fan and that seems to keep in down to a minimum. Could be better. It's always bad in the spring when we get the frost coming out and the concrete will sweat. Venting is an option, just don't have the time I guess.

 

get a fan, cheap breezebox (15 to 20+ "), plug it in, low speed, and don't turn it off
the circulating air will not allow the condensation to accumulate on the floor or your tools
always leave the fan ON.............only the power of a 40w bulb
try it, it works

 

Leave a fan running as long as someone is in the area. I never leave a fan running when I leave the area, fans are cheap in more ways than one. They gradually dry up over time, slow down and can start a fire. I've heard of it happening more than once. Not to start a panic, just being sensibly cautious.

 

Turbine vents run for free and they won't start fires.

 

Yo!
As a transplant to So Carolina, I have scratched my head why both my little Butler garage and older detatched garage got floor moisture.

As one who has installed ridge vents, fans and all, I can tell you it is a help but not a cure. My Mustang interior mildewed and tools and the metal garage cabinets get surface rust.

The culprit is often sudden temperature differentials, specifically the 'sweaty' days are when warm moist air comes in after a cold period. Your floor is cold, and so are most metals. SWEAT!

I discovered both my garage floor and butler pad had been poured DIRECTLY on the clay ground, which is a helluva cold sink.

My new garage was properly poured over many inches of gravel and has zero problems.

I am thinking about putting down gravel, coarse sand or soem solid insulation and pouring another floor on top.

Any masons out there?????

 

Midnite Cruiser,
What you've also got is ground moisture wicking up into the concrete. That's what is making the thermal conductivity from your slab to the ground. Sand and/or gravel helps with drainage and dryer makes a better insulator.

 

I did not mention that I epoxy painted the floor too. When dry, its much nicer to get clean, and the grey is nice and bright.

Whether the floor is actually wicking all the way thru the paint or not, I sure agree with you Mc Guyver that some kinda insulating layer would be a big fix.

Just not sure what minimum depth of sand or gravel , then what minimum depth of new cement topping would be stable over the 4" now in place. Any combo over 6" would require me to jack up the whole building perimeter to get more bolck or brick under there for additional floor!

 

I'm looking to buy a place that has an old garage with obvious moisture coming up through the slab. I can certainly vent the garage, but is there any practical way to block the floor moisture, or am I looking at replacing the slab and placing the proper gravel and moisture barrier under it?

 

When installing a floor slab it is common practice around Kansas to install a moisture barrier of plastic sheet. The epoxy probably helped a little. After the fact about the only thing to do is vent. Venting will still allow warm moist air to come in contact with cold metal and concrete in your shop. This temperature and humidity cycle is what causes a lot of the rust on your vehicles and corrosion on electrical system connectors etc.

 

All,
You guys are almost right, but no cigar!
Ask your self, when do you see the moisture. It's in the morning.
The garage cools down, so does the slab, but more slowly. The slab has a significant mass and the ability to hold/store heat. It heats up and cools down more slowly than the air. Garages are not the best sealed structures with the garage door and open soffit returns. As warm moist air enters the garage in the morning the cool slab condenses water out of the air.
Ventilation is the solution. Heating is the other. Hot air will not condense moisture,cool air will.
If you've got moisture coming up through the slab, you are royally screwed. There is little you can do to stop that. No paint will stop it because the concrete will be too wet to paint.
A strange incident I saw one time, was a clothes dryer blowing into the garage. it put alot of water into the area. If your looking for a water source its most likely the air.
KingFisher
Professional Air Conditioning System Designer