W/O seeing the terrain, it's hard to say. I guess, in short, what you need to do is be SURE of the SOURCE of the water.
Perhaps the landscape is too HIGH up on the wall where it's almost 'even' with the sill. In my municipality, it's recommended that the landscape be 9" or more BELOW the sill. This is to 'discourage' termites as well as prevent rising water from entering the house. I think it would be best to have a few Contractors pay a visit, especially Contractors that specialize in Excavation and Foundation work. (Most of these Pros are Masons, so do ask what they specialties they have as part of your background check.)
If you can't find a Contractor that specializes in Excavation and Foundation Repair, contact your Municipal Inspector for some leads OR ask him if he knows any Material Suppliers in that line of work. The Material Suppliers are the guys that, well ..., sell supplies to the Excavation and Foundation Repair pros.
Your suggested solution may not work, or it may be more than what's required. At the same time, have you inspected your gutters and downspouts? Do they leak, or are they 'missing' where there should be gutters? Are they improperly hung? ANd are the downspouts emptying water right at the foundation? Does the landscape around the foundation slope TOWARDS the building??? These 'things' are the usualy contributers to water in the basement (or wherever.) During the next rainstorm (baring lightening), don your boots and raincoat and take a walk around the building, looking UP as well as down. Be sure that rainwater isn't the cause of your problem(s).