Need guidance on sealing exterior walls from moisture intrusion
I need your help defining the next step in getting a moisture issue resolved on our first floor. Our house has a slab foundation, and when we bought the house we noticed a some signs of moisture intrusion around the exterior walls (stained carpet along walls, light mold on baseboard in limited areas). I called in a enviro guy who looked in the walls, etc and couldn't find any active mold infestations, but every year when it starts to rain we get a slight musty smell downstairs.
I believe part of the problem is that someone poured a solid concrete slab patio essentially all the way round the house, and it butts up against the exterior stucco right at the base of each wall. It seems to me that this pushes water that runs down the exterior walls right into the very very small gap between the exterior and the slab.
I plan on having someone re-do our backyard, and as part of that have them remove the slab, but I'd like to make sure there isn't anything else I should be doing.
1) Thinking of having a french drain put in around the house to facilitate drainage.
2) Since the exterior is stucco (50 year old stucco) should we be looking into having the stucco "sealed" or replaced with something more water resistant?
3) Once the exterior concrete is removed around the perimeter is there some sort of flashing one could install around the house slab to prevent any water from seeping under the wall's base plates?
Any other ideas? If you had to do this, who would you hire? I'd guess the landscaper could take care of the exterior concrete patio, but I doubt he would be able to do any work to seal the walls, so I'm confused about who I should be talking to to get this issue 100% resolved.