Q When we removed an old carpet pad from our quarry-tile floor, it left a green stain on the tile. The pad is made of jute with a rubberized backing. Will you suggest a cleaning method? We want to have the quarry tile exposed. Doris E. Elliott Pebble Beach, Calif. Fortunately, quarry tile is a very hard, durable material and can withstand almost any type of cleaning material. I would recommend that you rent a floor-scrubbing machine with rotary brushes and steel-wool pads, using a good floor stripper or wax-remover solution.
To get that new shine again, treat the floor with one of several unglazed tile sealers which are available from your local ceramic-tile distributors. Q I have a problem with moisture seeping through the cinder-block foundation walls of my 18-year-old house. The moisture causes a white powder to form on the walls. What should I do? Wilmer C. Landry Berkeley, Calif.
The basement walls were probably either waterproofed with tarpaper or hot-mopped with asphalt or an asphaltic emulsion. These materials will lose their oils and become dry and brittle, especially near the surface of the ground where the moisture content of the soil is constantly changing.
I recommend you seek the advice of a couple of ``below grade'' waterproofing experts and ask for a written proposal for their work and the type of guarantee you will receive.
To go beyond remedial work is very costly as it involves digging down and exposing the wall and removing the old waterproofing material by scraping and/or sandblasting.
I have re-waterproofed by using Elasto-Deck BT by Pacific Polymers, 15702 Container Lane, Huntington Beach, Calif. 92649, as well as Tuff-n-Dri by Owens-Corning, Fiberglas Tower, Toledo, Ohio 43659.
After applying the new material, place a perforated drainage pipe, sloped to a drain point, along the footing and cover the pipe with about a foot of crushed rock. Add a layer of tarpaper to discourage roots.
Before completely backfilling the trench, place a 2-foot-wide band of asphalt-saturated Celotex, with its top slightly above the grade, to prevent any gardening tools from damaging the new membrane.
Be sure you have good drainage away from the building. A sound roof drainage system of gutters and downspouts is also a helpful preventive measure.
I also recommend that you write to United Gilsonite Laboratories, Scranton, Pa. 18501, which manufactures a variety of nationally distributed products that may more readily solve the problem.
Q I need some advice about concrete. First, fine cracks have appeared in our patio slab. Second, the dividers between the concrete walk slabs have sunken and the slabs have separated. How should I repair the slabs before they become worse? Jean Ostrowski Bridgeview, Ill.
Freezing and thawing of wet ground, as well as water in the cracks, play havoc with concrete. Patching the fine cracks will require an epoxy grout. Two of the many manufacturers are:
Thermal-Chem, 1400 Louis Avenue, Elk Grove Village, Ill. 60007 (Telephone 1-800-635-3773).
Burke Company, 2655-S Campus Drive, San Mateo, Calif. 94403 (Telephone 1-415-349-7600).
To keep moisture out of the slab joints, use a flexible urethane sealant such as Sonolastic Paving Joint Sealant, made by Sonneborn Building Products, 415 East 16th Street, Chicago Heights, Ill. 60411 (Telephone 1-312-747-8700), or something similar.