Basement Humidity

[gfernandez]

I am almost done finishing out the basement, only carpet and plumbing left to go! The tools have all been moved from the garage down to their new home, and I am now in the process of laying out where all the tools will go.

One question I had was about basement humidity, specifically, with regards to sheetrock & mold, and the woodworking tools & rust, what should the maximum humidity be? I've searched the internet, but there does not seem to be a good consensus about this. The current humidity runs between 55% and 65%, depending on the day. I have a variable speed unit for the basement that helps, but am unsure if I need to purchase a dehumidifier (or 2 if 1 is dedicated to the shop).

Gonzalo

 

[Glennbear]

My former shop was housed in the basement and I found that above 50% became problematic. I solved my concerns with a portable dehumidifier. If you end up looking for a used one let me know as I will be likely selling mine since I have found no need of it in my current detached shop. :wsmile:

 

[Joe Scharle]

Mine is on a raised stand prety close to the basement return. Raised stand allows gravity drain of the water collection bucket via clear tubing to HVAC sump pump. Clorox twice a year keeps the tubing clear of scum. I set it a 35%.

 

[DaveO]

My shop is a day-light garage, with three walls almost completely buried and the other is a roll-up and walk door. I can get humidity levels up to 70% in there especially in the summer and when I am working with the walk door open. I do have a dehumidifier and use it often, but not for the protection of my tools. I store a lot of lumber in my shop, some AD and use the DH to reduce the RH so the wood will dry.

Dave

 

[Sealeveler]

Let me know what you find out.I have a bad moister problem in my basement.I can't figure out why,it could be because my elevation is 7.7':rotflm:.Tony

 

[CrealBilly]

dehumidifier

 

[Tarhead]

To paraphrase a popular comercial jingle: "Gottawantaneedahgettahava dehumidifier" if you live in the south and have a basement. <50% Relative Humidity will prevent mold spores from germinating and rust. Once you get mildew it's about impossible to get rid of it. We ran a big dehumidifier in a 1000sq/ft finished basement in Asheville and ran the condensate into the floor drain.

 

[JimmyC]

The perfect temp./humidty for a humidor to keep cigars moist is about 70 deg. Farenheit/ 70% humidity. So I would say that you're looking for under 50% humidity :gar-La;.

 

[Bas]

In the summer, my basement will typically be at 50-55%. Not a problem. It gets as high as 65-70% sometimes, when I don't run the A/C because it's still relatively cool. No mildew, mold or rust issues. I suspect I might have issues if the humidity was 60%+ for a sustained period of time, but under those conditions I usually turn on the AC anyway. In other words, as long as you give the basement a chance to dry out, you should be fine.

The small dehumidifier I have seems to do an adequate job. It might be a tad undersized, but why spend more?

 

[ErnieM]

Since my shop is air-conditioned I thought I had the humidity under control. Last summer we went up to NY for a couple of weeks to visit the kids. I left the air-conditioner on in the shop. When we got home, I was greeted with 70% humidity in the shop and a harpsichord with 5 broken strings. It seems while we were away, the temperature dropped in NC to the point where the air-conditioner didn't kick on. I live across the street from Chocowinity Bay so the humidity is pretty high even when the temperature isn't. Lesson learned. De-humidier bought.

Ernie

 

[dkeller_nc]

Regarding rust on tools, I've found that if the shop goes above about 60% R.H. above about 75 degrees, I will find a nice coating of rust on all exposed steel surfaces. To that end, I keep a dehumidifier running in the summer so that it stays less than 50% R.H. in the basement shop.

P.S. - If you buy one, spend the extra $$ for an ultra-low temp model. If the temp in the basement falls below about 65, most "ordinary" dehumdifiers without a defrost cycle will freeze up, which just makes the electric meter spin without doing anything.