There are alternatives to flagstone for swimming pool waterfalls.

Each year, thousands of Arizona residents email or call Rosie Romero’s radio show with questions about everything from preventing fires in their chimneys to getting rid of tree roots invading their sewer systems. His goal is to provide answers that suit the specific lifestyle wherever someone lives in Arizona.

QUESTION: We have a spa with a waterfall that dumps water into our swimming pool that was built in 2001. The problem is that the spa is surfaced with flagstone, and flagstone was also used for the waterfall.

I don’t believe the waterfall was built properly as it allows water to run down the sides and also under the lip of the waterfall. As a result, there is a lot of white calcium buildup around the waterfall, and the flagstone face of the spa is wearing away. I’d like everything to be properly re-constructed, but I have no idea what type of contractor can do this work. The company that built our pool is no longer in business, by the way.

ANSWER: Flagstone may not have been the best material for this application as the calcium bonding agent in the stone is prone to leaching when constantly exposed to water. The effect you are having is called “efflorescence.”

Because of constant water exposure, the calcium is released from the matrix of the stone and accumulates on the surface. While flagstone is very attractive and has multiple uses, a swimming pool waterfall feature probably is not one of them. A qualified pool contractor can give you alternatives for a different material better suited for your pool-waterfall-spa.

Q: My home built in the 1940s was retrofitted with an air conditioner some time ago. However, despite the retrofitting, there was an old swamp cooler left behind that somehow has rusted out my AC ductwork. I know I need to replace that area of the duct, but I wondered if there are any new low profile ducts that are more efficient that I can install to eliminate the old ducts that are encased in the drywall and actually make for a lower ceiling in the bathroom and bedroom.

A: Rigid ductwork can be fabricated into just about any shape you may need, but the ducts need to be sized appropriately to the area they will serve. In older homes built in the ’40s, the ductwork was really not designed for air conditioning, and AC compatible ducts were not actually available in the housing market place. So, contact a professional AC contractor to have them come take a look at your duct system and recommend changes based on your specific conditions.

Q: My 27-year-old concrete, S-style tile roof needs to be redone. What is your opinion about using raised wood battens versus no battens at all? Do battens really keep the roof cooler? One contractor who gave me an estimate recommended adding O’Hagin roof vents. What do you think of that product? I do think my 1,200-square-foot house could use more ventilation as it has only two gable vents right now.

A: An S-tile concrete roof tile has a rolling design that re-creates the gentle curves of roofing tiles in the Mediterranean area. With that type of tile, roofers often install battens, strips of wood used to fasten tiles onto the roof. The tiles have tabs on the back that hook over the battens, and in most cases, the tiles don’t have to be nailed in place. O’Hagin vents are attic vents designed to work with tile roofs; they do not protrude above the roofing line, and they blend in with the tile. As with any attic, ventilation is always required, and those vents would be a good idea to supplement the gable vents you already have.

For more do-it-yourself tips, go to rosieonthehouse.com. An Arizona homebuilding and remodeling industry expert for 29 years, Rosie Romero is the host of the syndicated Saturday morning “Rosie on the House” radio program, heard locally from 8-11 a.m. on KNST-AM (790) in Tucson and from 9-11 a.m. on KGVY-AM (1080) and -FM (100.7) in Green Valley. Call 888-767-4348.