First of all, I know this garage will never be dry. It's a standalone, one car garage built into the side of the hill that my house sits on. It abuts the neighbor's yard, and they have landscaping and flowers they frequently water. My neighbor even says the garage gets more water in it when they water a lot.
Garage http://plk.webimages.s3.amazonaws.com/garage1.JPG
The garage has a rubber roof with two gutters that do not effectively drain water. The aluminum edging is not sealed to the rubber, so I'm guessing most water goes straight down instead of into the gutter. There is brush cover on all 3 sides of the garage.
Gutter closeup http://plk.webimages.s3.amazonaws.com/garage4.JPG
Inside is a concrete floor with some cracks. The walls are unsealed cinder block. Even though it has been dry, you can see how much moisture is here. Should I try and seal the walls with DRYLOK?
Inside garage http://plk.webimages.s3.amazonaws.com/garage2.JPG
My ultimate goal in drying this out is to build a small climbing wall in the garage. It will be 2×4 frame with plywood. I don't mind if it's humid, but I'd prefer that it not smell strongly of mildew. I don't want the wood to rot from moisture.
Plan of attack and open questions:
- I have considered digging a trench around the perimeter and installing a simple drain tile system. Is this worthwhile? How deep should I go?
- DRYLOK the walls?
- Obviously, fix the gutter system and roof.
Anything else I should do?
Best Answer
I think you're going to have a lot of problems trying to prevent water/moisture in this garage.
As you say, improving the gutters is a good first step. It's likely that there is no drainage system around the foundation of this garage, so that is going to cause some trouble. You may be able to mitigate some of the ground water by putting a french drain around the outside, and draining it off to the side somewhere away from the garage. It doesn't need to be too deep (6" is probably enough), but there should be a gravel bed wide enough that any of the water that would drain around the walls is diverted (remember, water will follow the path of least resistance).
Ultimately, despite drainage, you're going to have problems with condensation. As the warm humid air meets the cool foundation, it's going to form condensation on the walls. This is unavoidable, since it is a garage and has a giant opening to the outside. If you build the frame around the inside in such a way that there is still air flow for drying, you may be able to reduce the effect though and at least somewhat prevent the smell. Definitely use pressure treated wood for everything here.