Hangar humidity

FastEddieB

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Fast Eddie B
We’ve been in our hangar home for several months now, with very few problems so far and loving it.

But the other day, I first noticed the windshield of the Sky Arrow was fogged up with moisture as it sat in the hangar. Later, the floor was damp all over...

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...and the seams in the concrete wall were also showing moisture...

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My guess is the temperature and dew point were close, and this was all just dew condensing on any cooler surfaces in the hangar.

I was wondering if a dehumidifier - or several - would make a difference. Home Depot’s biggest:

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Anyone else had this happen, and if so, how did you deal with it?
 
Turning up the heat would serve a secondary purpose of heating up those surfaces that retain cold once the weather warms up, rather than trying to pull water out of the air.
 
Anything from a home center will not be effective in a hangar.
Try
Therm-a-stor dehumidifier
 
Turning up the heat would serve a secondary purpose of heating up those surfaces that retain cold once the weather warms up, rather than trying to pull water out of the air.

This.

Assuming you have HVAC in your hangar, this should take care of the humidity issue.
 
Turning up the heat would serve a secondary purpose of heating up those surfaces that retain cold once the weather warms up, rather than trying to pull water out of the air.

Thanks. Our hangar is unheated, but I suppose I could run some sort of space heater if I knew conditions warranted it.
 
Thanks. Our hangar is unheated, but I suppose I could run some sort of space heater if I knew conditions warranted it.

That’s the punishment you get for living somewhere with mild weather...sounds like you wouldn’t need or want a heated garage/hangar. Me? My dream is an infrared system that keeps surfaces toasty. It can literally rain from the beams in some hangars. Saw one last week that was foggy inside.
 
Where you see condensation like that is when the weather makes a rapid change from cool or cold to warmer. The cold soaked surfaces serve as a place for condensation to form.

Dehumidifiers or a heater are the solution. They actually sell 250w heaters for the inside of cars. One of those set inside the Sky Arrow would probably keep condensation from forming in or on it.
 
Better ventilation will help. Letting cool air in, and moist air out is kinda counter-intuitive but it works! But then you may have to pre-heat...

-Skip
 
Anything from a home center will not be effective in a hangar.
Try
Therm-a-stor dehumidifier

Thank. I checked their website.

One hitch - their dehumidifiers show a minimum operating temperature of 49°F. The temperature during my “dew” scenario was quite a bit cooler. But I suppose if the unit is operating before and after the dew event when the temperature is higher, it would still help a lot.
 
Thank. I checked their website.

One hitch - their dehumidifiers show a minimum operating temperature of 49°F. The temperature during my “dew” scenario was quite a bit cooler. But I suppose if the unit is operating before and after the dew event when the temperature is higher, it would still help a lot.
Some models "ice up" if it's too cold; I had one that did that. It's cheaper than heating, when conditions allow.
 
Thanks. Our hangar is unheated, but I suppose I could run some sort of space heater if I knew conditions warranted it.

If it's unheated I would try ventilating it well, before incurring the cost of heating it.
Is there any warm, moist air entering from the house during cool weather?
That much damp on chronic basis risks mildew and mold.
 
Thanks. Our hangar is unheated, but I suppose I could run some sort of space heater if I knew conditions warranted it.

Well, that explains that. It'll cost a few AMUs, but a long term solution would be to get an HVAC unit. The money you spend on that can quite possibly be saved down the line in future maintenance bills or humidity damage.

As far as running it is concerned, you can get an automatic thermostat that will automatically switch between heat and AC. You can keep the temp in a wide range. When I'm gone I have my hangar set for 55-90 degrees. That way you're not spending much on heating/cooling bills, but the HVAC will still keep the humidity down.
 
Do something. Mold won't be far behind. If I were you? A simple ceiling hung gas forced air heater would be my choice. Heat and air circulation in one. Maybe adding an additional ceiling fan or three would make sense, too.
 
Have seen plenty of concrete floors where someone decided a vapor barrier was too expensive; moisture from below. Is your ground saturated right now?
 
Have seen plenty of concrete floors where someone decided a vapor barrier was too expensive; moisture from below. Is your ground saturated right now?

Applies to the concrete wall too, if no external waterproofing barrier was applied before backfilling.
 
I appreciate the thoughts, but this was a transient condition, and the ground has been way more saturated than it is now and I know the walls were waterproofed. Not sure about a vapor barrier on the foundation. Pretty sure this was dew condensing from above and not moisture from below or without.

Some fans for circulation sound like a good idea, with or without heat.
 
When Carrier invented air conditioning, he did it to control humidity. By cooling the air he was able to remove moisture. The problem with controlling humidity in your hangar is that it is partially underground and therefore has a great heat sink to work against. Any moist air close to the walls will cool and the moisture will condense. If you insulate the walls, the moisture will condense in the insulation and that is bad.
It would be futile to try to heat the heat sink that is the Earth.
You could try to cool the whole hangar to the same temp as the Earth-backed walls but that would be crazy given that you want to open the hangar doors.
Circulating fans will keep the air moving and may keep it from condensing. This is probably the most economical.

I would also suggest that you paint the interior walls with Kilz. The smooth paint will allow the condensation to run down the walls. Use vertical strokes so that there are channels to the ground and then have a couple of inches of saw dust along the bottom to catch the water. Then sweep it out and replace it occasionally.
 
I have two hangars at Bremerton, which is built on an old lakebed. The hangar with the epoxy floor is wet every "Pineapple express."

The bare concrete floor hangar is always dry.
 
The easiest, least expensive way to relieve the condensation? Open the door and leave it open.
 
If it's unheated I would try ventilating it well, before incurring the cost of heating it.
Is there any warm, moist air entering from the house during cool weather?

This. You'd need some pretty hefty dehumidifiers to take care of a hangar, and just blowing the same air that's already too moist around, while it may help somewhat by shrinking the temperature differential near the cooled surfaces, isn't going to get rid of any moisture. Some sort of ventilation that can exchange air with the outside is probably the cheapest method that wouldn't require leaving the door open (which will let in bugs and critters, which can be much worse than moisture).

Also, make sure that you're not allowing too much air from your house into the hangar. (If the two are connected, which "hangar home" says they are, to me...)
 
I leave a big fan running in my hangar 24/7. It gets rid of all that wet stuff. I have the largest box fan that Tractor Supply sells. The slab is the problem... One of my hangars is horribly wet so I put the fan. My other hangars stay dry.
 
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