Keeping a Pole Barn dry enough for tools

[California]

Lots of good advice above, particularly on designing to stop the continual chimney effect.

I have a couple of minor points to add:

Paraffin, possibly mixed with solvent, is a good silicone free sealer for equipment.

You might consider a waste-oil heater.

 

[JB4310]

I live in Connecticut,we probably have the widest swing in humidity, in the summer it can get so bad that water droplets form on the floor joists and drip (in house basements) on the floor, hardwood floors get so tight they can buckle, you must use dehumidifiers or a/c's. In the winter it gets so dry we have to put wet towels on the radiators to put some moisture back in the air, the hard wood floors get 1/8 gaps in some places
Regarding shop type buildings, I had a 50x60 with 18ft. ceiling, I swear I saw clouds forming in there under certain extreme weather conditions, my steel top tables, vises,anvils etc. would have standing water on them when the warm wet air met cool hard surfaces (steel first but could affect wood also)
Suggestions; though its hard for me to understand winter humidity, first of all what Cris mentioned about the ceiling and the vented space above would be the best solution but that is not always practical in a shop type building where a high ceiling is needed. I would suggest a couple of dehumidifiers for your size space, keep the doors closed as much as possible, I don't think super heating it once a month would work, the oil filled heaters would help some and would keep it warm but electric heaters even set low can get expensive (I have a 5000 watt heater in a 600 sq. ft. building set at 40 degrees and it costs over $100. a month), the dehumidifiers would take gallons of water out of the air every day, that's what they are made for and don't use as much electricity.
You want to keep the leaks out of course but a few drips wil not add much to the overall humidity problem, insulate as you can afford to, it is the best way to create a stable enviroment.

Good luck John B.

 

[GuglioLS]

One more thought and I'll get out of the way.
Insulation - I highly recommend closed cell foam vs Fiberglass or whatever that blown in stuff is. Closed cell foam will not absorb or allow moisture to pass through. An insulation contractor once told me that Fiberglass insulation in damp areas is like having no insulation at all. That's my last 2 cents worth. Whatever you do and whenever you do it, I wish you all the best.

 

[DaMadman]

Instead of all this heating and cooling and Insulating... on and on..

Why now just buy a few cheap Dehumidifiers and run them ?

 

[tomrscott]

I've never used a dehumidifier. Sounds like it could be a good part of the solution in the worst weather.

What do these cost, what's a good brand, and are these something you get at a drugstore? Or something more "industrial strength?"

Do some of them turn on based on a humidity sensor just like a heater can be controlled by a thermostat?

Thanks!

 

[mwood]

I have a dehumidifier in my basement. You set it to a setting and it automatically turns on when the humidity reaches that pre-set setting.

One note -- they use cold coils (much like air conditioners) to collect water. If you have them in a very cold climate they can freeze up and break. Just something to think about.

Mine is a generic brand found at Lowes. Worked well for two years now and runs a lot in the summer. It keeps my entire basement dry in the summer though. I think it cost me around $65. Again, not that big, but it does the job for me.

 

[bugstruck]

Mad, Good idea on the humidifiers but he still has have the air changes (mixing) in the building under control first. I've seen some metal buildings doing a complete air change in maybe two hours with no mechanical (powered) ventilation. Just by convection and indoor/outdoor temp. differential. Even if he's at 2 or 3 air changes a day the humidifiers will be considerably taxed and struggle to keep up. There is also the indoor temp issue with unheated buildings and cold ambinet (outdoor) temps and the way humidifiers work. If he simply put a hard ceiling in and operated humidifiers during all but the coldest months, a fair argument could be made the situtation could become tolerable. One would actually have to check the safe operating temperature range of the humidifies intended for purchase. Some are probably rather forgiving but below 32 degrees it's a no- brainer. I believe they'd freeze up before that though.

 

[Luremaker]

I am just finishing the inside of my 40x60 shed with 14' ceilings. I insulated the entire floor with R7 blue foam and the walls with R23 and the ceiling with R44 straped and drywalled the entire building. Then I put up a R23 insulated inside wall for a heated section which I heated very little this past winter. This humidity would vary between 45% and 60% in the whole building. The thing I noticed the most was the inside temp never dropped below 40F this winter even when outside temps were 18 to 20 below for two weeks.

I added ceiling fans which really help keep the temperature even when I turn on my electric shop heater. A few more weekends and I should be done the inside. Then I can get to the landscaping on the outside.

This summer I plan on building a hot water solar collector to help heat the floor on those sunny winter days. /forums/images/graemlins/laugh.gif

 

[tomrscott]

I think the de-humidifier is a real good suggestion. Going to price those asap.

I also think that controlling the convection flows is probably correct as well. Trouble is, there is no drop ceiling or any way to create one in this type of building. Much more like the open-beam ceiling in a barn. But since we really don't have any significant heat problem, I am thinking about just sealing up the roof and walls tight with no passive ridge or gable vents at all. If I insulate the building well, I think the grease pit gives me a very large geo-thermal ground temperature sink that will keep the whole barn cool.

The hardest thing to seal is going to be the giant sliding door, but even that can get some flexible rubber gasket seals that will help a lot.

I wish I knew whether there is any insulation under the plywood on the lower walls, but I kind of doubt it. Probably nailed right up to the inside of the 2x6 stringers that the sheet metal is nailed to on the outside.

Even on the hottest days, the workshop is always quite cool. Now, granted that is with the current air flows, but I think the slab and pit are the major things keeping it cool. If I found that there was too much hot air accumulating under the roof, I could add a gable fan with a vent that closes if it isn't running. Most of the year, the outside temp runs between 30degF and 60degF, with summers ranging from 60degF to 90degF and a few days over a hundred in the middle of the day. Always cools down substantially at night.

We just don't have that much heat to deal with, and what heat we have is pretty dry heat. The humidity is fog and rain in the fall/winter/spring.

/forums/images/graemlins/smirk.gif

 

[tomrscott]

Regarding insulation types:

You mention the problems with fiberglass vs closed cell foam.

Are you referring to the foam that comes in large sheets? I've seen half inch and one inch thick, with or without foil on once face. I can see that moist air could flow through fiberglass, but then the foil or tarred-craft paper facing should minimize that quite a bit. How do you get the foam to seal into a space well enough that the air doesn't just go around it? Do you have to cut it to press-fit clearances, or do you use one of those spray foams to fill the gaps?

Or were you referring to filling the whole wall space with some sort of expanding foam product that you spray into a hollow space? I think I saw a demonstration of that on an episode of "This Old House." Those shows always seem to use the best of everything with unlimited or near unlimited budgets, so I wonder how expensive that stuff is, but I'll bet it works real well. This was not the retail products you buy in an aerosol can, but something installed with large equipment. It must have had a well-controlled rate of expansion to keep the wall spaces from bulging. I can see that stuff might work very well, especially with corrugated metal on one side.