optimal humidity range for basement shop?

[Zignot5]

I just moved to a new house which has a dirt floor basement. I'm worried about keeping my tools down there due to the high humidity. I put 6 mil plastic as a vapor barrier covering the dirt. I have installed a dehumidifier, but it uses so much electricity. It runs 24/7 to keep the humidity at 65%.

How dry is dry enough?

Any suggestions for this situation or should I abandon it as a shop?

[alaporte]

I'm not an expert by far but I would suggest pouring a slab in the basement.

As for me my basement shop has poured walls and a slab, it stays at 35% to 45% with a dehumidifier running.

AndyL.

[Zignot5]

That has crossed my mind.

Thanks for the input

[walnut_weasel]

I try to keep my shop at or below 50%. Since I have started doing that keeping the rust off my cast iron is a much easier task. I typically only see rust where my oily fingers have been. If I try to get it down below 45% the dehumidifier never shuts off.

[walnut_weasel]

Another thought crossed my mind. What are the walls made of? Concrete block is like a sponge. Maybe a combination of the vapor barrier and a good sealer on the walls will have the effect you want with less cost.

[Trip]

50% or below will [probably] give you a seasonal range of between 45% and 60%. But an average of 65% means it will drift will above that. That's too high.

[Zignot5]

Thanks for the input everyone.

I'm going to try a sealing masonry paint for the walls that are block. for the 2 walls that are old dry stacked stone I'm going to have to fill and point before I can seal them. Pouring a slab in there isn't going to happen any time soon.

I tried shutting off the dehumidifier for 2 days, now that I have the wood boiler fired up. Even with the added heat in the basement I'm hitting 80%. Not going to put any tools down there until I get it sorted out.