I have a detached building that was originally constructed as a garage, then crudely converted (by previous owners) to living quarters about 40 years ago. By 2009, the structure had deteriorated to near-collapse and I hired a contractor to renovate all but the slab. The first winter after completing that work, water seeped in around the slab & thru the section of the original foundation that had not been replaced. A French drain had been installed along the rear and one side of the structure 20 years earlier, but it had not been positioned low enough to be effective. The slab along the rear wall is below grade and the original French drain had been located ABOVE the slab.\r
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At that point, I interviewed several contractors to correct the drainage problem
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