I moved out into the country last year and have a big pole barn now for my shop. It's 30' x 40', and the peak of the roof is probably about 20'. I've been really struggling with condensation and humidity, and rust. It's off the hook. Like the truck I'm working on right now is sitting there basically rusting in my shop. You can literally see the rust progressing. I'm wondering if any of you guys have had similar problems, and what you did to remedy it. I've thought about a dehumidifier, but it's a big space, and I don't know that that would do much. I've also thought about getting some big fans to keep the air moving and keep things perhaps dryer. But I don't know. I've got three garage doors across the front, two large and one normal. I leave them open on nice days to get sunshine and fresh air. Any suggestions are most welcome. Thanks.

 

presume that your shop is insulated?

does the floor sweat? look wet

what temp did you keep your shop at last winter?
this was happening at where i work... (a 40'x50') we used this building to store raw,(un-machined), parts, & they were just about as rusty as they would have been outside. Basically the building is kept too cold during the winter, any time one opens a door it lets in a fresh batch of moisture and never gets warm enough to bake, (so to speak), the humidity out before the next time the door opens again. fast forward to spring/summer and now more humidity is migrating in.

1) turn up the heat above 55-60* for winter. & run a fan
We did this last winter and it was MUCH better. Even though someone might go into the building only a couple times a day.

2) yes a fan or 2 will be a great help...a dehumidifier or 2 strategically placed, certainly couldn't hurt for summer either. Be aware dehumidifiers can be energy hogs.

3) if it really that much of a issue you might be wise to air condition the place for the summer months....especially if your trying to do body work

Maybe try a big window A/c unit and see if that helps.

 

I would start with venting in a shop that big, gable vents, or any kind of venting. Im guessing it has a sheet metal roof and sides with no insulation if it is a "pole barn" They are not exactly climate friendly. They sweat. On the roof though there should have been a vapor barrier between the trusses/perlings and the sheet metal. Most of the time the sides did not get that.

Does it have a concrete floor?

Anyway, cheap and easy would be start with venting. You can even get a gable vent that has controllable louvers and a built in fan.

 

Yes, it is a pole barn with metal roof and exterior. It has a concrete floor. The walls, ceiling, and garage doors are insulated with 2" rigid foam panels. The ceiling has blown in on top of the rigid foam. The insulation was already there when I bought the place. I've been here for about 1 year.

Rust has been a year round problem, but right now is the worst time of year, with the way everything cools off at night and heats up during the day. I think I maybe need to keep the place closed to keep warmer outside air out as much as possible. But that kind of sucks, because this time of year, who wants to keep their garage door closed? I hadn't thought of roof venting; I bet that would have to help. I'm just amazed at how much worse this building is than a normal garage. I've got machinery I've owned for years, and just one season at this place has been harder on it than the whole rest of the time I've owned it combined. I need a hunchback who does nothing but wipe things down with an oily rag.

Enriched, the shop was unheated this last winter; I worked in the cold; I haven't had the money to heat it yet. But yes, my experience was a lot like yours; the metal I keep on hand for blacksmithing rusted like crazy.

 

willing to bet that there is no ridge vents on the roof.
If no to the ridge vents then you need to address that pronto....like Toyz was saying...either ridge vent or gable vents. Your trapping a lot of in the humidity in the rafters.

 

Actually I was mistaken; there is a ridge vent. I just wasn't familiar with what they look like on a metal roof. I still think more ventilation might in order though. Also, do you know, will an epoxy floor sealer do anything to prevent migration of moisture up from the concrete?

 

Hmmmm my first thought is that if one "seals" up concrete that has a tendency to be damp...it will stay that way, to some degree. My gut says to leave it so the moisture can escape, aka breath. The thought here is dry cement stays longer.

The only way sealer will prevent moisture migrating through cement is between the ground and cement...yeah a top coat will stop, or dramatically slow getting into the room, but one might be subjecting the cement to premature life span by staying wet/damp. Mind you, cement life span is pretty long anyway.

Gonna go out on a limb and say that there is no eves trough,( rain gutter) on the roof...or if there is, that there is little to no drainage tile around the base to help evacuate ground water from the perimeter of the building foundation....considering that it was a pole building/shop...then it prolly just slab cement and no foundation to act as a barrier for the moisture from migrating under the floor.

just a thought ...a body shop in my home town put in floor heat system. to help with moisture migrating into the shop through the floor...the owner absolutely loves it...seeing as he always on the floor working on vehicles so he stays warmer and the work stays better...so he's getting better quality of work out the door. The catch is he did this when he built his new shop. Not sure if this can be added after the fact. might be wise to contact a Heating /AC shop to see what they recommend. or maybe a concrete contractor.

 

It sounds like you have drainage problem that is causing the humidity inside the shop. If you have any standing water around the outside figure out how to make it run off away from rhe building.

That and the venting should make a huge difference.

 

I was mistaken; there is a ridge vent. I wasn't familiar with what they look like on a metal roof. There is an overhang and soffit as well, with soffit vents. There are gutters, but there are no perimeter drains, and the grading in front of the shop results in rain puddling there. I've been planning to put in some drainage tile around the perimeter; just haven't gotten to it yet. But clearly there is water getting under the slab.

I see what you're saying about not sealing the floor.

The way the ceiling is insulated is with rigid panels laid across the horizontal members of the trusses. So to some extent the shop space is isolated from that attic space. I guess what I'm trying to say is, when I get all this humidity in my shop space, I'm not sure how much of it gets out through that ridge vent anyway. Definitely need to try to keep the humidity out as much as possible to begin with. But still need to figure out what to do with the humidity that does get in. I'm wondering if a couple of wall vents/fans up high but below the ceiling would help.

 

It might be the soffit ventilation in the eve side of the roof is not working properly...maybe plugged?? It Great that you have that ventilation in place.

some night...set ladder up along the soffit and smoke test it and see if you can see the smoke exit out the ridge vent...should happen pretty fast. The ridge vent is the best way to help control heat build up in the rafters, there by helping your shop area to stay cool

For Right Now ...get a big window air conditioner and a good sized de humidifier...maybe a couple of fans. If you like to keep the door open during the day, then keep the a/c & dehumidifier off and just run the fans...close everything up at night and let them suckers run all night...you prolly find that even during the day it will feel better and the doors stay shut, especially as the summer heat ramps up. Really doubt that having the door open during the day that you'll make much head way into the issue though.

My dads basement always was damp...until we placed better perimeter drainage...until that happened he got a hold of some old furness fans , ( burners, or fire box, or some thing was shot), wired in a plug in for the motor for constant on. Sometimes you can keep the duct work enough to keep in place the furness filter... relatively cheap and they move tons of air. They helped manage the dampness pretty well for a long time. Chatting with a Heating and Cooling shop really can be helpful, they will have a better solution

then work on the perimeter drainage.

We also have had a extremely wet spring...must be make up for lost moisture from last years dryness.

 

I got up on the roof and took a closer look at what appeared to be a ridge vent; the spaces between the seams in the metal roofing are filled with a solid rubber material, not one that is designed to let air pass. So there is no ridge vent. That will be the first thing I do, take the ridge cap off and remove that membrane; and put one down that keeps rain out and lets air out; then put the ridge cap back on top of that.

I also plan to add one or two dehumidifiers and start keeping the doors closed; and add some perimeter drainage. Thank you guys very much for your thoughts. I really appreciate it.

 

Those are to stop the rain from blowing under the ridge cap. They make some that are perforated.