Please advise.It would help if we saw pictures of what you are considering.Metal is probably best because it won't dry rot from moisture or contact with the ground and animals can't chew/scratch through it.Any general contractor or a good handyman should be able to help you with this project.

Also, an Air conditioner will work more efficiently if there is less moisture in the air (Houston, Florida, Alabama, etc).  

They can also be a liability however if there is a moisture problem that cannot be easily solved.

Something about moisture transfer, but he showed me where bits of mold are starting to form on the roof beams.

I informed them that the reason mold keeps reappearing is because of the moisture in the room when showering.  

Tenant agrees to allow Landlord timely access to premises to do maintenance and repair.Tenant will notify Landlord in a timely manner of any damages or problems as they arise, including damages caused by Tenant, malfunction of appliances or fixtures, and water/moisture leaks and spots.Tenant will take care of the premises, keeping them clean and clear of debris.

Washington, lot's of moisture there? 

Buy a moisture meter and live by it.

It also has a tendency to soak in any type of moisture that touches it, to include, drinks, food, urine and other bodily fluids.

At this point, the power has been off for over a year and no attempts to manage the moisture (even with a regular dehumidifier) have taken place in atleast 3 years.