Patching a crack in concrete

Question: The house we moved into a couple of years ago has an added-on room with a concrete floor. Now there’s a crack in it at the transition line, about three-eighths of an inch wide. Can we fix this?

Answer: At this point it’s too late to make a permanent, structural repair without spending a ton of dough. We suggest sealing the crack with special caulking and monitoring the gap to see if it widens. Use a rubberized, self-leveling concrete caulking compound, which is flexible and will expand and contract with the floor from season to season. This may not prevent the gap from getting worse, however. If it continues to widen, consider having it looked at by a structural engineer who can recommend a permanent fix.

--

How to get rid of hot tub mold, lime

Question: We’ve had a hot tub for about two years, and we recently cleaned it. We drained it, took out the jets and found them covered in lime. We tried soaking the jets in one part vinegar to two parts water, but it didn’t help. There are also brown spots on the underside of the lid. What would you recommend?

Answer: For the jets, soak them in pure vinegar and wait 24 to 48 hours. This should remove the lime. The dark spots on the lid are most likely mold. Try this mildew-removing formula:

Mix one-third cup of powdered (ammonia-free) laundry detergent and one quart of liquid chlorine bleach in three quarts of hot water. Add the bleach to the water first, then the detergent. Be sure to use rubber gloves and eye protection, and have plenty of ventilation. Pour the mixture into a spray bottle and soak the mold until it turns white. Keeping the area wet, scrub with a nylon bristle brush. Rinse immediately. Dry the surface right away, or the mold may return.