I am in the process of having a new house built, and would like to know if there [TEXT OMITTED FROM SOURCE]

Can you suggest something such as a sealer for this purpose? -- J. D. M. A Using a sealer over tile can create more problems than solutions. A sealer might make the sealed surface more slippery, which would be a safety hazard. A number of tile manufacturers no longer will guarantee their product if the tile has been sealed. This includes American Olean and Summitville Tile.

If a sealer is to be used, check with the local supplier of the tile and obtain a recommendation from the tile distributor for what materials have worked with their products. The best solution is using a neutral base soap for regular maintenance with ceramic tile surfaces, and this includes walking surfaces. Q I have been contemplating putting a blacktop coating over our cement driveway. I like the rural look it will give. Plus, it will hide car drippings that have accumulated during the past few years.

I've never heard of anyone doing this, and friends I've mentioned this to have insinuated that I am not playing with a full deck. What, if any, problems would I encounter?

I just assume the blacktop coating will adhere to cement. I understand it periodically will need resurfacing to maintain a fresh look, but I can live with that, if I can accomplish my end results. -- E. S. A Yes, blacktop can be applied over concrete. I suggest that you consult a contractor in asphalt paving and resurfacing for details on how the new surface would be applied and a cost estimate. This type of contractor will be listed in the Yellow Pages under paving. It is best to get more than one estimate and references from previous customers.

Another method of changing the cement look would be staining the existing concrete surface. Today's concrete stains are solutions that react chemically with the lime in concrete to give permanent coloring. They penetrate the concrete and cannot peel or wear away as a painted coat can. The color choice is limited generally to earth shades of red, rust, green, tan, brown and black.

Cleaning the concrete for staining often requires only a good scrubbing with water and trisodium phosphate. If the concrete is stained with oil and grease, use mineral spirits to remove these before scrubbing. Q I have a carved oak entry door that periodically is exposed to direct sun and indirect rain. I bought it unfinished and sealed it with exterior Watco Danish Oil Finish. Now, parts of the lower routed details have developed black penetrating stains, specks and streaks where moisture apparently collected.

What are these discolorations, how can they be removed and what exterior treatment or finish will offer the best protections and lowest maintenance for a door in this location? -- S. L. A The wood needs more protection from exterior elements than the Watco finish provides. Before you apply a new finish, the stains must be removed.

First try this method of cleaning.

Use a fine grade of steel wool with a good floor cleaner or mineral spirits to clean each spot and the surrounding area. If that doesn't work, sand with fine sandpaper, feathering out a few inches into the surrounding area.

If the spots remain, you'll have to try the more drastic treatment of an oxalic acid. Questions about construction or care of the home may be addressed 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.