Humid climate> damp garage> rust on everything!

[...dave]

i recently moved to a new place with a very nice attached 30 x 32 garage with 12-foot walls that gable at close to 20'. However (there's always a however), i'm having a tremendous problem with moisture. i open my toolbox in the morning, and there is a layer of condensation on everything. i have a few sets of those shelves with metal frames and unfinished particleboard tops, and one of them collapsed because moisture softened the PB; i made the mistake of storing my contingency water supply jugs on another set, and the undersides of the shelves are covered in mold!

So, this may sound like a really stupid question, but, the garage is not insulated and does not have interior finish- it's a stick construction- will i solve my problem if i insulate, or make it worse? (i have no idea how the slab was prepared). Is there any kind of dehumidifier i could reasonably purchase and run for a space that large (over 11,000 cubic feet)? Any other solutions come to mind? (obviously i try to keep a light layer of oil on my tools, but that's only a stopgap)

Cheers,

...dave

 

[1320stang]

Heated shop? are you in a high humidity area? Might be moisture wicking up thru the slab.

My buddy has a chassis shop, metal building with the large plastic rolls of insulation. He thought he'd get some muratic acid to mop the floors with to make them look nice. Left the mop bucket in the building, next day EVERYTHING that was bare steel was coated with a layer of rust. Tools, welding benches, customer's 'moly tubed cars....

 

[Old Moparz]

I have a minor dampness issue in my garage, but it doesn't come anywhere near the problem you have. I do get some mold in a few places & I'm working on better ventilation to help. I have 2 ceiling fans I've been leaving on constantly to keep the air moving, but I haven't been doing it long enough to notice a difference yet. When I was using a portable "Cover-It" garage, I installed two gable vents, one at each end of the structure. This cut down quite a bit on condensation on the ceiling & car.

Do you have vents in your building?

Is there a ridge vent at the peak of the roof?

What about soffit vents?

Any roof vents, mechanical or not?

I know if you try to eliminate the conditions that cause the dampness & mold, you also need to eliminate all of the mold or it will come back again later after you've corrected the problem. It'll still grow since it's already there now. Kind of like pulling weeds by the root, not just trimming them. If the building is in a shaded location, that will add to the problem since the sun can never get to dry it out.

I'm also thinking you might have to put in some kind of exhaust fan, or maybe a attic type fan.

 

[z28toz06]

you have to determine where the moisture is coming from.
Then you need to figure out where the temperature swing is coming in to play.
put some plastic sheeting on the slab and see where the moisture collects. Does it get cold in there at night and heat up during the day?

 

[z28toz06]

http://www.jameshardie.com/pdf/irc2006.pdf

http://www.usg.com/products/moldandmoisture/mmPosition.jsp

one of the sheetrock manufacturers has just come out with a cloth covered wall board product. the theory being that mold was feeding on the paper facced(and backed) wallboard. don't know which one though.

 

[Stuart in MN]

Therma-Stor makes a very good dehumidifier called the Hi-E Dry. Go to their website at http://www.thermastor.com/, then go to Products > Commercial Dehumidification. They're on casters and they plug into a regular 120vac outlet so they're easy to use.

I'm an electrical engineer, and a big part of my work is electrical design of water treatment plants. These places typically contain giant tanks full of cold water, which equals plenty of condensation. The mechanical engineers for these projects routinely spec these Hi-E Dry units, and they work great for keeping everything nice and dry.

 

[Robert]

Low garage temp at night, high garage temp in the day combined with humidity causes condensation on your tools, water cans, etc. Just like taking a can of soda out of the refrigerator, it forms condensation until it reaches ambient temp. You need to bring the RH down. I have a Whirlpool dehumidifier that solved my humidity problem, as high as 80% in a 20x20 garage, now 30 to 36%. The unit Stuart in MN linked to looks really nice. The only other option is LPS#3 on everything. Good luck.
Robert

 

[useless]

A dehumidifier should help provided the garage doors aren't kept open for long periods of time. I have a problem when I wash cars in the winter and have since bought a dehumidifier and that controls the problem. I would see where all the moisture is coming from along with getting a dehumidifier. Insulating won't help the moisture problem but might help in maintaining the temp.

 

[...dave]

Thanks for the tips!
The area i live in is generally very humid. The garage has no heat or AC, just a ceiling fan. It has soffit vents and a single, very small gable vent. i really need some kind of exhaust fan system in there anyway, because the heat is just staggering in the summer... i'm just very reluctant to cut into a finished building. Guess i'll have to get over it and mount some ridge vents before the summer comes... i will definitely check into the commercial dehumidifier units, although, since i have to ask, i probably can't afford them...

Cheers,

...dave

 

[oldcarfart]

I am moving to Clinton (near Spartanburg/Greenville) do you live along the coast as I have those issues now in Jacksonville, Fl. but upstate SC appeared to be less rust prone.

 

[kbs2244]

If you don't plan to heat or cool, all you need is circulation. Your temp and humidity will thae be the same as the outside air.
If you have soffit vents but only a small gabel vent, then you don't have enough exit for the hot, moist air that builds up during the day.
The easy thing to use is those wind powered spinning ball type turbines.
They move a lot of air, and do not need any power or maintaince.
Install them high, close to the ridge. On the back side, so no one complains about their looks, and forget them.

 

[mjribeiro]

I have a thermastor whole house dehumidifyer - it handles 2500 sq ft, too small for you but I can attest to the quality - if they sell bigger units I would bet they will do the trick....

 

[DarrenD]

Most likely there was no vapor barrier under the slab before it was poured.
Try to install more vents, as well as a dehumidifiyer, as others here have suggested.
Your condensation problem sounds extremely exessive, there are small canisters that are available at storage units, or even you local Home Depot or Lowes.
The small canister I have used in a garage for moisture problems, looks to be @ a quart in size will "treat" up to @ 100-120 square feet.
You may need to double up on something like that, or go for the gongo size.

Good luck.

 

[Krodad]

It's due to the temperature fluctuations in the garage...the tools and other things cool down over the long evening and nightime periods...then the garage heats up quickly in the morning. Now you have the cool contents of the garage in the hot, humid environment, and then you get the condensation.

I think if you were to insulate the garage very well, and keep it somewhat tight, the rapid fluctuations will be decreased in the morning and you'll be good to go. Even super-ventilating won't help all that much...a little, just probably not enough to solve your relatively extreme problem. You can't do anything about the slab if it was not poured over a vapor barrier or insulation.

If you insulate and add a standard household dehumidifier, I'd reckon the problem will be solved...you'll just have to determine whether you insulate directly against the roof sheeting, or install a ceiling and insulate that way. Make sure you have adequate ventilation if you end up with an attic!

 

[snorvet]

Last summer I put a dehumidifier in my shop because the nuts and bolts on my workbenches were getting a little rusty. The dehumidifier runs about a third of the time through the summer and it feels a lot cooler in there, and no more rust.

 

[kbs2244]

The dehumidifiers are only going to work if you keep the place closed up. Otherwise you are trying to dehimidify the whole county.
I used to sell stuff to car dealerships and part of my territory was Puerto Rico. Plenty of heat and humidity down there. The dealership's garages had walls that were just chain link fence! Nothing solid.
Please, no PR jokes. These were Mercedes and such places. Lifts, mechs with $3000 aand $4000 worth of tools in Snap On boxs. Everything you would see in Boston or St Paul except walls.
The key was circuliation. They always have a wind down there. It was a humid wind, but it was moving the air. They never get the sticky, still, humid days we can get.
If you move the air, you won't get condensation. Vent, vent, vent.