Do It Yourself: Concrete solution to repairs

Q. A chunk of concrete the size of a large grapefruit broke off the corner of one of our porch steps and shattered. Can I repair this myself?

A. You need a small amount of concrete mix, a small container of concrete bonder, and some scrap boards or plywood. The boards are needed to fashion a mold or form for the new corner.

Start by setting up your form. Arrange the boards so they make a pocket that will shape the new corner when you fill it with concrete. Hold the boards in place with bricks, concrete blocks, or whatever heavy objects you can find.

Next, brush concrete bonder on the broken surface of the step, following directions on the container for application, drying time and so forth.

When the bonder is ready, mix the concrete and pack it into the pocket formed by the boards, using a small trowel.

Smooth the top to match the top contour of the step and round off the outside corners slightly with your trowel, also to match the rest of the step. Let the concrete set up for several hours, then carefully remove the boards; they should come away without sticking.

Smooth the outside faces of the patch with a damp trowel and your new corner should be a good match for the original.

Drape a plastic bag over the corner to keep it from drying out too fast and spray it with water a couple of times in the next day or two.

Q. My Formica kitchen counter is badly stained and I have tried all types of cleaners without success. Can I paint the counter?

A. Plastic laminates such as Formica can be painted, but the finished surface will be a lot less durable than the original. The paint will be subject to stains, scratches and won’t be as resistant to moisture and heat.

After you paint, the best bet is to buy several cutting boards and put them in areas where you do cutting, use hot or heavy cookware, and so forth. In fact, this is a good idea even if the surface is original plastic laminate.

To paint, start by cleaning the surface with a kitchen cleaner-degreaser, which you can buy at any supermarket. When the surface dries, sand it lightly with 150-grit sandpaper. Go easy with the sandpaper; the purpose is to just remove some of the gloss, but don’t break through the laminate layer.

Next, prime the surface to keep the stains from showing through and give a good base for the finish paint. A good choice is Zinsser’s Smart Prime, which is a stain killer as well as an excellent base on glossy surfaces. The primer is white, but can be tinted to roughly match the finish color.

I would use a 100 percent acrylic enamel to finish, applying it with a small, mohair roller or a high-quality brush. You can buy the roller in the paint department of a home center. Two coats of finish paint gives the best appearance and durability.

Q. I recently moved into an old house that is not insulated. I’d like to add insulation, but don’t know where to start. Can you help?

A. If the house is completely without insulation and has some of the other energy problems usually found in old houses, making it energy efficient could be expensive.

In general, the best place to start is the attic or roof, where most of the heat is lost. Fortunately, many old houses have unfinished attics that are relatively easy to insulate.

Insulation can be blown into the attic so it settles between the floor joists, or fiberglass blankets can be installed between the joists. Blown-in cellulose is a good choice because it has good insulating value and can reach out-of-the-way areas that are otherwise difficult to reach.

An experienced contractor should be picked to do the work, and several other important things should be kept in mind. One is that vents should not be insulated; outside air must circulate above the insulation to prevent condensation and other problems.

Second, old electrical wiring should not be buried in insulation; it can be a fire hazard. Have an electrician check the wiring and make sure local electrical codes are observed.

Third, check the attic floor for gaps and air leaks and seal them before insulating. Fourth, find out how much insulation should be installed to best prevent heat loss.

To check the recommended amount of insulation for your area, visit www.naima.org, the Web site of the North American Insulation Manufacturers Association. Type Insulation Map in the search space, then click on How Much Insulation.