Walk-in Vault Humudity

[Saggins]

I recently got permission from my better half to turn our basement tornado shelter into a walk-in vault (as long as I leave enough space for it to still be used during an actual tornado). Its approximately 22' long 3.5' wide and 7' tall. I was trying to think how to control humidity and was leaning towards a room dehumidifier inside, emptying as needed and a heater in the winter months (the ceiling is poured concrete that is also our front porch and when it was below zero outside the room got down to roughly 40degrees).

Does this seem reasonable or are there better alternatives? And is $150+ for a 30pint dehumidifier overkill for the space?
The other side mirrors this, just without the gun rack.

 

[Fine Figure of a Man]

I keep a tub of desiccant in my walk in safe and it has been adequate. The lower level of my house has a heated floor, safe included and I'm sure that helps a lot.
Sounds like a couple inches of foam board insulation on the ceiling of your room would help.
Any way to run the dehumidifier to a floor drain?

 

[1KPerDay]

We have a permanently installed dehumidifier with an auto sump pump that goes on when the reservoir fills. If you get a portable one be sure to check the reservoir regularly. They fill up quick if it’s humid.

 

[Saggins]

In my haste I just realized I misspelled humidity in the post title... /facepalm

And no, no way for an automatic drain without considerable cost.

Insulating the ceiling is a good idea, I think I can glue some up. On a side note, what do you think is an adequate temperature? Currently I have a small heater maintaining ~60 degrees easily.

 

[ericuda]

You are going to get extreme temp changes with roof/porch above ground level. I would condition the area with the rest of basement with both conditioned and return air. If it is isolated temp swings and concrete open to outside temp via porch will not be easy to control. Dehumidifier is a must.

 

[Saggins]

Our basement has a dehumidifier running essentially year round, what if I put an exhaust fan in the vault door? I could force conditioned air into the room... and it would be our house's very stable basement temperature, possibly removing the need for the heater

 

[ericuda]

That would be a start to condition the room. How old is the house and have you noticed any moisture on the ceiling.

 

[Chuck R.]

When we had our house built I almost went this route with the under the porch space. Instead our builder suggested doing under the 3 car garage, because the ceiling slab has greater protection due to the garage above (and a a lot more room). We still planned for a dehumidifier with built in floor drain and the room is on it's own geothermal heating/cooling zone. During construction we had the chance to observe some serious condensation during the winter on one section of wall that was exposed. That led to insulating and dry walling the entire space.

Winter I run the heat at 65, summer I run the dehumidifier and the room stays at about 67.

I would look at insulation at least for the ceiling. There's no getting around the effect of warm air hitting cold concrete. I'd definitely put in a dehumidifier and plan on replacing it every "X" number of years, cause the majority just aren't built to last. Running HVAC into the room might also be another viable option.

Do some research on dehumidifiers, at one point a lot of the recommendation I read were for going slightly undersized so it ran more.

 

[film495]

I'd think your biggest trick would be to bring the temp up a little in the winter - and not dry the air out completely, which is bad for wood. Although, I don't know that the temp going down to 40 or even lower is of any real concern. Define what range you want to keep it in - and apply a plan for that. You could get one of those little remote weather sensors, so you can glance at it and see if all is good, or if you need to check on it.

that rack sure looks nice, and also a little lonely all empty like that …. lol

 

[Saggins]

it didnt stay empty very long...

Thats my bulky temporary heating solution. I have seen moisture on the walls/ceiling before I waterproof painted it. But I havnt seen any signs of moisture with the heat and dehumidifier going (regardless of outside temperatures from 5 to 50)

 

[CapnMac]

You probably want a humidistat, and to keep track of how it ranges.

If you can, you might want to see if you can source some slatwall, which you could run up the wall, and lay the weapns out horizontally and higher up to get more use out of precious space. The slatwall, with its finished surface would laso help "warm up" the space a tad, too.
Go price out vinyl plank flooring (an easy install over conccrete) to help take some to the 'stark" out--which would be a good thing for a shelter, as well.

 

[herrwalther]

Make sure you have a good hygrometer in there as well. One that measures the temperature and humidity range is invaluable when it comes to firearm storage. At any point, you can look at most hygrometers and see a humidity of 50% lets say. What you won't see is during heavy rain storms for example, humidity can spike to 86%.

Depending on how often you are in there, an auto drain dehumidifier will be the better investment. If you aren't going in there regularly to empty a dehumidifier tank, it is useless to you. I have a small half gallon dehumidifier in my bedroom closet where one firearm is stored. It is small enough it isn't in the way and I go into that closet 3 or 4 times daily. Plenty of chance to empty the tank every other day when it is full or close to it.

 

[film495]

in a small space, the dehumidifier will generate quite a lot of heat as well

 

[bullet maker 57]

film495 hit the nail on the head. All I have in my room(10x12) is a dehumidifier. The temp is stable year-round.