IN THE MAIL: More letters on the problem of paint adhesion to the lower part of stucco walls (Dear Dale, April 14, May 5):
Lee Koelfgen Jr. of Rainguard Products Co., 821 W. Hyde Park Blvd., Inglewood, writes that paint failure at the lower part of a stucco wall can be solved by the suggestions in the May 5 column only if the failure is caused by rainfall or sprinklers.
"Unfortunately, neither of your readers (responding in the May 5 column) has considered a third cause. Most California homes exhibiting this problem have stucco extending below ground level. Stucco will absorb moisture from the ground and 'wick' it upward. This moisture will either deteriorate the stucco underlying the patched and waterproofed areas (eventually causing a failure of the repair) or it will (on a south or west exposure) have enough vapor pressure buildup due to sunlight to 'blow' an impervious coating off the wall.
"The ultimate solution, of course, is to waterproof stucco below grade with an impervious material to prevent wicking. The lazy man's way is to saw cut the stucco slightly above grade (a kerf cut through the stucco to the concrete footing) and fill this kerf with a waterproof caulking that interrupts the wicking. A subsequent waterproofing application above this saw cut can then be totally effective."