Steam cleaning fine when fixing old floor grout

Q. I have a foyer in my house with randomly placed square and rectangular stones glued onto wood flooring. This was done in the '80s. None of the stones have loosened in all these years, but I am losing grout and some of the stones are worn near the edges (due to salt, I believe).

I am having the loose grout replaced with a sanded grout (I believe this is what I have now) and a sealer put on the finish floor.

The person doing the job recommended steaming out the old grout. Some is loose and some tight in the same spot. Less labor intensive. I am concerned that the steam will loosen the stone tiles.

Also, what is the best time of year to do this? What do you think?

A. I assume that the steam cleaning of the grout is to clean it. It will only help loosen some of the grime, it should not affect the solid grout or the stones. It will still be necessary to scrub the grout to remove any gunk the steaming will not remove.

If done by an experienced mechanic, steam cleaning should not affect the stones except to clean them as well if the steam is applied to them. Since the work will be indoors, there is no bad time to do it.

Q. What's the best way to clean the grout in my ceramic tile floor?

A. For a professional job, see answer to previous question.

But if you wish to do it yourself, you can mix an oxygen bleach powder, such as Oxy-Boost (www.ecogeeks.com), in warm water until saturation (when some powder can no longer be dissolved) and apply it to the tile floor, making sure that the grout lines are thoroughly flooded.

If the mixture is quickly absorbed, pour more until it is no longer absorbed.

Although the oxygen bleach should clean the grout in a half-hour or less, let it stand for as long as you can and lightly brush it after 20 minutes or so.

Oxy-Boost is environmentally safe and will not harm any fabric or other finishes.

Q. Will be escaping the cold of Chicago for a few weeks for a sunnier/warmer climate. What advice can you pass on to safeguard our house and car while we are gone. Assume we should turn off the water but what about the hot water heater, and things like that? Should we have someone start the cars from time to time or just let them be?

A. The safest thing to do is to keep the heat on at 50 F. to safeguard the water supply and your belongings, which can suffer damage when exposed to cold temperatures over an extended period of time.

You should shut the breaker to the water heater so as not to use electricity unnecessarily, or, if you have a gas water heater, have your plumbing contractor shut off the gas supply for the same reason. He or she can also shut off the water supply at the service entrance for additional safety.

If you have family members or trusted friends nearby, it is a good idea to give them a key and ask them to check the house regularly, particularly after a power interruption, to make sure that the heating appliance is functioning properly. It is possible that the appliance may not restart automatically.

You may also want to consider purchasing an alarm system, which will automatically call several telephone numbers you have programmed in case the temperature in the house drops below the selected setting on the thermostat. You can find a number of these alarms by Googling "Freeze Alarms".

As to what to do about your cars, this is a question best answered by your servicing garage.

Q. What is the best way to remove caulking that has mildew underneath it and to redo it after?

A. The caulking, most likely silicone, is known for mildewing. You should be able to release the edges on both sides of the bead, using a sharp knife or utility knife, being careful not to damage the surrounding areas.

Then pry out one end with a screwdriver, grab it and pull out as much of the caulking as will come; you may need to use players. You may have to repeat this a number of times.

You will have to remove any residue and mold spores in order for new caulking to adhere properly.

Any residue can usually be removed by scrubbing with a stiff brush and mineral spirits, but do not use mineral spirits if the adjoining surfaces are painted or have a similar finish. In that case, substitute denatured alcohol.

To remove mold spores, clean the area with a Clorox bleach solution in warm water, using a sponge. Let the area dry overnight.

Choose a caulking with anti mildew properties, such as Sashco (sashco.com.), which has a strong 7-year warranty, including labor to clean and redo the job.

Others are GE Supreme Kitchen and Bath, DAP's KWIK SEAL PLUS Kitchen & Bath Adhesive Sealant with 5MICROBAN, etc.

Q. Cluster flies used to bother me in May and the fall. Now it is January, and I am still inundated with them. On the second floor, they are even worse. Have to get them out of light fixtures often. Seems like whole house needs to be ridded of them. But how?

A. Cluster flies enter the walls of houses in the late fall through any cracks and crevices they find, seeking shelter for the coming cold weather. They come out of their hiding places within walls on warm, sunny days through any cracks around window frames and trim, baseboard, etc. If you can find these cracks, seal them with suitable caulking.

Cluster flies are not "dirty" flies in the sense of posing health risks as other flies can, but they are annoying and, if crushed, smelly and messy.

One way to get rid of them is to vacuum them up as you see them; another is to hang fly paper near windows as they come out during warm spells. I have also heard, but not tested, that placing orange peel on window sills works by discouraging them from clustering on the window panes.

But the best way to prevent an infestation is to caulk and seal every joint between different materials outside - around windows, doors, beam projections, cantilevered joists, etc. It is also essential to caulk the joint between the foundation and the mudsill if it does not have a sill-sealer.

You can also have an exterminator spray the south and west walls of the house in late August or early September to keep cluster flies from taking shelter in your siding.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.