Parts Shed

[Mac74]

I need some guidance on a shed I recently had built. I’ve asked this question on other forums and I got so many conflicting answers until it just confused me more. So I thought I would put it on here and see if I could get a little clarification:

It’s a 10x12 wooden shed with a wood floor. It has a shingled roof and sits about 16 inches off the ground on cinder blocks. No vents were installed on the building and it was not wrapped with Tyvek or anything. The purpose of the building is just to store automotive parts from my Mustang projects. I’m in North Carolina so of course I’m fighting humidity.

I generally try to wipe everything down with a little oil before I store them. What would be the simplest way to seal the shed up so I could use one of those portable AC/Heater/Dehumidifier units? I was thinking if I line the entire inside of the shed with construction plastic and then wall it in with OSB, I should be good. But I was told the plastic could sweat behind the OSB and cause mold and moisture. My alternate plan was to just leave the shed as is, install a vent on each end, run a little small fan inside and put some DampRid inside.

I would appreciate it if someone could point me in the right direction. I have an actual shop and since this is just an overflow building for parts, so I’m not trying to put a lot of money into a full blown installation/renovation project.

 

[gearhead1]

I'm not in construction, but I would think you'd be best to put plastic on the inside and run a dehumidifier.

I also live in NC and have problems with tools and parts rusting with vented storage.

 

[gungatim]

I would put a vent or a window in the end wall. open it an inch or so for ventilation. as long as the air and temp equalizes you shouldn't have much problem. if you are really worried, coat the parts with some oil...

just like a crawl space under a house, it's ventilation that you want, not sealing it all up.

 

[Captain Spaulding]

Cold metal parts + Warm moist air = Rust

Water condenses out of the warm air onto the cold steel because the air warms up faster than the steel. Happens in the morning when the sun comes up after a cool night or when the weather changes.

Ventilation won't help much with that issue. Keeping the parts warm or keeping the moist air from getting to the parts would do the trick. Sealing the shed and installing a dehumidifier will work.

Another option that I used to use when I was into old tractors is applying a coating to the metal that keeps the moisture away. I think the simplest was a pound of paraffin dissolved in 2 quarts of mineral spirits. The better you can crumble the wax, the easier to get it to dissolve. Spray or brush it on the metal and let it sit in the sun to sort of dry. Fluid film or Boeshield may give the same effect.

 

[GMCGarage]

Insulation, vapor barrier, drywall or plywood. Not sure how to do the floor, maybe some 2" ridgid foam then another layer of plywood.

is there something else you can put in there that wont rust, and keep the parts in the main garage?

 

[Mac74]

Thanks for all the responses and this is what I was looking for. So I would be okay with lining the entire shed with construction plastic on the inside (including the top), then wall it in with OSB? Then run my little dehum./heater/ac unit to maintain the temp. and humidity. It was also suggested to me to line the bottom of the shed with the construction plastic. I know the shed wont be air tight, but I'm thinking it should be good enough to let the unit work.

I get confused because as gungatim said, I'ver read and been told if I dont have vents the plastic will sweat and cause moisture behind the OSB. My thought is that the unit will be vented to the outside so would that be sufficient venting.

Sorry for all the questions but I'm knowledgeable of construction matters and I hate to put something up that's causing more harm than guide. And again, I know that if the shed is not sealed air tight and insulated well, the unit will not perform optimally, but I hope it will reduce the rusting.

Thanks again for the replies.

 

[bdbecker]

I think dry air is more important than heating/cooling the space - sealing it off and running a dehumidifier would probably be sufficient. Just make sure to setup a drain hose so you won't have to constantly dump out the tank during the spring/summer. If you want, you could setup one of those $20 remote weather station sensors so you can keep an eye on the humidity in the shed. I wouldn't worry about heating/cooling the space unless you are storing liquids in there that you want to keep from freezing. Think about the desert - it gets cold at night and hot during the day, but since there is very little moisture in the air, condensation on metal is minimal and they don't see the problems with flash rust like we get in the humid states.

 

[tfinniii]

A layer of gravel under shed will help keep humidity down under shed.

 

[James-W]

I think dry air is more important than heating/cooling the space - sealing it off and running a dehumidifier would probably be sufficient. Just make sure to setup a drain hose so you won't have to constantly dump out the tank during the spring/summer. If you want, you could setup one of those $20 remote weather station sensors so you can keep an eye on the humidity in the shed. I wouldn't worry about heating/cooling the space unless you are storing liquids in there that you want to keep from freezing. Think about the desert - it gets cold at night and hot during the day, but since there is very little moisture in the air, condensation on metal is minimal and they don't see the problems with flash rust like we get in the humid states.

I agree. I wouldn't bother with a plastic liner, but I would insulate and I would run a dehumidifier. The insulation won't stop condensation, but it would help prevent large temperature swings.

 

[ZacSpade]

I agree with BDBecker - Rust sounds like your biggest issue. Dehumidifier is the best option

I would try and seal off as much as I could. Even with a caulking gun and some sikaflex or gap filler, or even tyvek the inside. (sorry i am not sure what the inside of your shed is, Im assuming it's stud)

Will save you some money with your dehumidifier

 

[pop pop]

I have a similar hobby and shed. I insulated my shed except for the floor. It keeps the temperature swings slow enough to almost prevent any rusting - at least not for years, but will on bare metal over years.

I also rent a storage unit. Sweated like crazy. I installed plastic film on all sides, floor, and roof, with a curtain behind the roll up door. Haven't had a problem with moisture since. I think it just gives the temperature swings enough time that the contents warm almost the same as the air - thus no condensate.

 

[Mac74]

Thanks for all the replies. They were very helpful. Think I will go with the insulation, seal my OSB with some caulk and run my dehumidifier.

Thanks again!

 

[jimgood]

You might want to spring for a dehumidifier with a pump for the water so that you don't have to drain its bucket constantly. You can drill a hole in a wall or floor and run the hose through it. I know the dehumidifier in my basement needs to be emptied daily in the summer.

 

[James-W]

You might want to spring for a dehumidifier with a pump for the water so that you don't have to drain its bucket constantly. You can drill a hole in a wall or floor and run the hose through it. I know the dehumidifier in my basement needs to be emptied daily in the summer.

That's a very good idea. Actually, all the dehumidifiers I have seen had a drain on them so you can connect a hose and use gravity to drain off the water. A pump would work good too if the drain were higher than the dehumidifier.