Q) I plan to paint my concrete driveway, which has not been painted before. Will you please outline the procedure for doing this, including how to clean, seal and paint, and any precautions I should take? -- E.T.H.
A) Probably the best advice concerning the painting of concrete decks, walkways and driveways is not to paint them at all. In the long run you will only be making more work for yourself because the painted surface eventually will fade, peel or fail and will need recoating.
Satisfactory wear is even more difficult if you live in a wet climate. You may want to consider a colored stain or chemical treatment for a color change rather than paint.
However, if you want a total color change, paint is your only choice. Careful selection and application of paint are mandatory. You will need an alkali-resistant paint made for concrete and masonry. There are several brands on the market. Along with special brushes and rollers for masonry surfaces, these paints have made painting masonry relatively simple.
Surface preparation is equally important. First, be sure that the surface is clean; cracks, indentations and spalls should be filled and the surface should be otherwise intact before painting. Scrape any loose materials from larger cracks and patch the hole with premixed "sand mix." Smaller cracks (1 inch or less) and any thin surface patching can be prepared with a dry powder along with a latex liquid. The mixture provides better adhesion than regular cement. Wash away any oil and grease; remove dirt and other materials with a wire brush.
If there is a white, saltlike material adhering to the concrete, it is probably efflorescence. This is caused by moisture that dissolves salts in the interior of alkaline materials and carries them to the surface. Efflorescence must be removed before painting by brushing the surface. But do not wet the surface or more crystals will appear.
To ensure good paint adhesion, first wash the concrete with a solution of muriatic acid, which also will help any efflorescence problem. Mix one part acid to three parts water and be sure to add the acid slowly to the water, never the opposite. To prevent breathing the fumes, keep your face away from the solution. Wear rubber gloves, old clothing and eye goggles for protection. Wash away the acid with a garden hose and then rinse the concrete area again with a solution of trisodium phosphate, which will neutralize any acid left on the surface.
When you have completed your painting project, keep some extra paint on hand for touchups on peeling spots, which are bound to occur from a year to three years later. Do an entire recoating as necessary.
Q) I have a white marble hearth. While rolling in my wood stove fireplace insert, one wheel scratched the marble. What can I do to prevent the scratch from showing? -- G.I.S.
A) Small scratches on marble can be removed by a light, wet sanding with No. 400 sandpaper; use it with parallel strokes. Then polish with a marble hand-polishing powder (supplied by marble dealers) on a damp cloth to remove the etching. If the scratches are deeper, there is nothing I know of that will camouflage them.
Q) My front entrance is a terra cotta tiled floor. Three of the tiles in different locations seem to be loose. I have tried to lift them, but it seems like the grout is holding them down.
Is there a way to glue these tiles down? How do I get glue around the grout? I have not washed the floor because I do not want to get water trapped beneath the tiles. -- B.M.B.
A) If the tiles are loose, you will have to remove the grout that surrounds them and reset the tiles with adhesive. You can remove the grout with a sharp instrument, such as a screw driver or a special grout remover available from a tile dealer.
Once the grout has been removed around the tiles that are loose, you can pry the tile free. Reset them with tile adhesive and regrout with a grout that matches the existing grout.
Send inquiries to Here's How, Copley News Service, P.O. Box 190, San Diego, Calif. 92112-0190. Only questions of general interest can be answered in the column.