Shipping container condensation

[dnetherland]

I have two shipping containers at my property that I use for tool and tractor storage. They are located in south Mississippi where the summers are hot and humid. At times it seems to virtually rain inside the container from condensation.
Both are coated with Kool Seal roof coating. Any ideas on ventilation or coatings (inside or outside) that could help with the condensation.

Thanks
DN

 

[JB4310]

I've got a twenty footer, occasionally get moderate condensation.

Not much I can recommend except keep it sealed up tight. Not practical I know, but I think it's warm moist air that condenses on the cool steel. So either more ventilation or no ventilation.

I guess you could spray on insulation, but that might get costly.

JB

 

[timswi]

Could try covering the inside with 3/4" foamboard....temp equalization is the problem. Have the same issue with steel decking in the storage area in my house. Have to run silicone heaters and a dehumidifier in there to keep it dry.

 

[MotorSeven]

I would put in a solar roof vent & that would take care of the problem. I put a small marine one in a 6x10 utility trailer & it worked fine, but for a shipping container you will have to go bigger.

RD

 

[PILOON]

Install a metal roof vent, the square type with louvers on all 4 sides, well sealed where it contacts the roof decking..
One should do the trick but you also need to provide an inlet for the air to get in as the vent cannot suck from a vacuum, that would be best installed near the floor so that the vent can totally change the air out.
For a inlet vent I'd suggest the type with louvers as seen on the sides of house trailers and RV's. Again one should be sufficient and place it diagonally opposite of the roof vent location to get maximum cross flow. ( EG top rt front on roof and bottom left rear for inlet)

If you ever stood on the roof of a house near a vent you would sure feel the heat coming out of an attic, (heat and humid vapors go hand in hand)

Note that the turbine types have been proven much less efficient (and more troublesome) than the cupola types. They, by design, require a bearing to rotate which corrodes and freezes in cold situations.
RV type vents only work in one direction which is OK on an RV as you are pulling creating the wind (suction) but useless when static, in fact if the wind is the wrong way you would simply be pressurising the container and pressure would cause more condensation.

 

[dnetherland]

Could try covering the inside with 3/4" foamboard....temp equalization is the problem. Have the same issue with steel decking in the storage area in my house. Have to run silicone heaters and a dehumidifier in there to keep it dry.
__________________
Timswi
I thought of using foam board but was afraid of moisture behind the board causing the glue to release or letting mold form behind the board.

Install a metal roof vent, the square type with louvers on all 4 sides, well sealed where it contacts the roof decking..
One should do the trick but you also need to provide an inlet for the air to get in as the vent cannot suck from a vacuum, that would be best installed near the floor so that the vent can totally change the air out.
For a inlet vent I'd suggest the type with louvers as seen on the sides of house trailers and RV's. Again one should be sufficient and place it diagonally opposite of the roof vent location to get maximum cross flow. ( EG top rt front on roof and bottom left rear for inlet)

If you ever stood on the roof of a house near a vent you would sure feel the heat coming out of an attic, (heat and humid vapors go hand in hand)

Note that the turbine types have been proven much less efficient (and more troublesome) than the cupola types. They, by design, require a bearing to rotate which corrodes and freezes in cold situations.
RV type vents only work in one direction which is OK on an RV as you are pulling creating the wind (suction) but useless when static, in fact if the wind is the wrong way you would simply be pressurising the container and pressure would cause more condensation.

Piloon
I've been hesitant to place a roof vent because the roof is corrugated (ridges and valleys ) like the sides and I'm afraid I won't get a good seal and water will leak around the vent.

Thanks for the suggestions. Any others? It was almost like it was raining inside the container today.

DN

 

[svcguy]

I experienced the same problem and mounted a couple of passive air fans on the roof. These are the type that move by wind or heat rising. Although they didn't eliminate the problem, it helped quite a bit.

 

[forgeblast]

Just an idea, for green houses there are many solar powered vents that raise and lower when they hit a certain temp.

 

[Gary Fowler]

We use a lot of shipping containers for storage and even field offices. We cut in 6" tall x 12" long vents in the sides rightnext to the top about every 10 feet. You can use the cut out to make a shed over the hole then weld on 2 side pieces to make it rain tight and cover the hole with screen to keep out the insects. Then cut in some floor ventilation holes the same way. Natural convection will pull in cool air from bottom and exit at top. We never have condensation problems.

 

[Frankdozer]

I have a 20' container at my vacation home in Maine. I use it to store my snowmobiles. Even in the winter, this time of year, the ceiling is covered with condensation. Feels as tho it's raining inside. This happens all year. I was thinking of a small electric heater. Just enough heat to eliminate the condensation. It's caused by a colder outside than inside temperature. The only other way is to install high exhaust vents and low intake vents. Just like ventilating your attic.