Recently, I have heard about some contractor’s claim that gutters and drainage are a viable alternative to the moisture level system. While I have always maintained that maintaining proper drainage and limiting the moisture intrusion under a slab on houses built in the arid Southwest are a good thing and should be encouraged. We offer those techniques to customers as a method to control additional moisture getting under the slab.
What I don’t agree with is that they are a viable alternative in lieu of a MoistureLevel System, and the logic is fairly straightforward. In my upcoming blog I will share the process of sub slab moisture accumulation, where I show 3 mechanisms that facilitate this process.
The point that I want to make is that gutters and maintaining proper drainage really has no immediate large effect on the area that is experiencing the problem….. the place where the moisture accumulates the most, the center of the slab. See the diagram above. Notice where the problem is…. And now notice the area that is affected by installing gutters drainage improvements….. the edge!
What do you think the effect on the slab will be by drying the soil near the edges? If you have been following my blogs in the past you will know that as those clays dry they will shrink more.