Waterproofing the masonry of a brick-veneer house

Q. Other than applying a stucco finish, how can the masonry on a brick-veneer house be treated to make it waterproof? Spraying with a colorless silicon product is of little help. Leaks occur when the side in question is subject to a driving rain of long duration. All other probable causes have been cared for. Stanley Krensavage McAdoo, Pa.

A.All other probable causes of the leaks have been cared for, you say. Let's list a few: roof and window flashing, mortar joints repointed, cracked bricks replaced, and so on.

My impression from some experts is that a clear waterproofing on bricks may do as much harm as good. Naturally, this view is countered by those who advocate waterproofing agents.

For truly professional advice, I suggest you contact the Brick Institute of America, 1750 Old Meadow Road, McLean, Va. 22101. This trade group may have the soundest views on waterproofing exterior brick walls.

Our paint consultant believes that impermeability of a masonry wall is related to the quality of the joint mortar and its "pointing" at the time of erection. Was a moisture barrier placed behind the brick veneer before the masonry was laid? Such a barrier should have been so placed. If not, it's too late now.

Clear high-solids waterproofing agents, such as Thompson's Heavy Duty Water Seal No. 201, may be effective on exterior masonry. Of course, an opaque high-build coating would likely stop the leaks, but may change the exterior brick color.

Before doing anything further to stop the masonry leaks, heed the Brick Instit ute's recommendations. It knows its stuff.