Cooling problems in the house sometimes are due to improper ductwork. An energy audit can provide answers.

QUESTION: I use a rooftop air conditioner for my 2,000-square-foot home built in 1982. Two bedrooms that are right under the 10-year-old AC are often icy cold in summer while the kitchen stays warm. One additional problem is that we have old, tin, rectangular-shaped ductwork. An air conditioning company thinks we should replace the AC, but I think we should replace the ductwork. Our summer AC bills are about $275 a month. What do you think?

ANSWER: You should probably try to get a couple of estimates on what it will cost to repair the ducts and replace the air conditioner. Ten years old is not that old for an air conditioner actually. Some last much longer with proper maintenance. Another consideration is that you may not need to replace all the ducts, though you might want to re-route them to new locations in your house. You could probably get a lot more info and advice on your situation by having a home energy audit done before you do anything else.

Q: Is pressure-treated lumber safe to use for building walls in a vegetable garden?

A: We don’t recommend using pressure-treated lumber for any type of gardening. The problem is that pressure-treated wood has been infused with chemical preservatives to protect it from rot and insects. There is a risk that remnants of the treatment process will leach into the soil and can then be absorbed by your plants. But if you use natural wood instead, you can treat those boards with Garden-Seal, a safe, non-toxic sealant to increase their longevity and help prevent rot.

Q: I’m considering changing from my house with a gas furnace to using a heat pump? What do you think; will it work?

A: Unfortunately, that’s probably not a good option. If you have heated your home with that gas furnace in the past, the warm air coming out of a heat pump in winter will feel much cooler than what you can get from a gas furnace system. You’re probably not going to like the change.

Q: I want to plant a shade tree near my concrete driveway. I’m going to cut back on the concrete to create space for the tree, but I still wonder if the roots from the tree will damage the concrete as they grow?

A: Yes, that tree can damage the driveway eventually. Perhaps you can use permeable pavers on all or part of the driveway so that the water can drain through them into the planting area. If the roots damage the pavers, it’s easy to lift them out and replace them.

Q: I’m in the process of ripping up my carpet so that I can use the basic concrete slab for my flooring. But in doing that, I found a plastic tube coming up through the concrete near the edge of the floor and next to one of the exterior walls. I want to get rid of it, but is that possible?

A: After looking at a photo that you sent us, it appears to be an extra conduit for electricity that was never used and was later abandoned. You can use a cold chisel to cut it down and then repair the area with a concrete patch material.

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