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Carefully applied bleach could remove driveway rust stains

Q. I have rust stains on my driveway and garage floor from the rusting of my car's undercarriage. I also have some rust stains on my front porch that were caused from the drain holes of my planting pots. I want to get rid of them prior to sealing the concrete.

What can I use to remove the rust stains without harming my bushes and grass? What concrete sealer is the best to use on driving surfaces and on walking surfaces?

A. Try applying full-strength bleach to the rust stains with a brush of a size compatible with the size of the areas to be treated in order to avoid any runoff. If this is successful, carefully spray clean water to dilute and remove the bleach. Flood any nearby plantings with water before, during and after the rinsing.

If the bleach treatment is not sufficient, try using a saturated mixture of oxalic acid. You can buy oxalic acid crystals in paint stores. Mix the crystals in a plastic bucket in hot water to saturation.

Do not use metal containers or tools; use plastic or wooden tools to mix the crystals. Oxalic acid is very corrosive, so wear full skin and eye protection, and be very careful in applying the mixture, using the same type of brush as mentioned above. Once the mixture has done its job, rinse it as also stated above.

There are two types of concrete sealers: topical and penetrating. Penetrating sealers are the best and are permanent, but they only work if the concrete is absorbent. To check if the concrete is absorbent, sprinkle water on it. If the water soaks in, you can use a penetrating sealer, but if the water beads, it would be a waste of time and money. Topical sealers can be applied on any clean concrete, but need to be reapplied regularly - every one to three years, depending on use.

Q. We have indoor-outdoor carpet that is glued to floor tile in our lower-level family room. In one corner, paint was dribbled on a small section. Can you advise us on the best way to remove the dried paint?

A. The type of paint remover to use depends on whether the paint is alkyd- or latex-based.

If you know which paint it is, ask your favorite paint store to recommend a paint remover that is compatible with the type of carpet you have. If you can take a sample of the carpet to the store, so much the better.

I suggest you go to a store specializing in paints and coatings, as I am concerned that the average hardware store's staff is generally not experienced enough to steer you in the right direction; this has been my experience over the years.

Apply the appropriate paint remover to the affected area, using a scrub brush to work the remover into the fibers of the carpet. To remove the dissolved paint before it dries again, the safest way is to use a strong vacuum cleaner or shop vac. You may have to repeat the process.

Q. We live in a well-groomed raised ranch in Vermont. For the last two years, every time it starts to warm up, we get a variety of ants in our dining room and kitchen. They can be tiny ants or larger, black ants. We have no rotting wood in our yard. What can I do?

A. Try MaxAttrax Ant Bait. It does not work on all types of ants, such as carpenter ants, which require the services of an experienced pest control operator, but it does work on most. I have had very good results with this bait. Be sure to follow the directions for safe placement.

Q. As summer approaches, we would like to paint or stain our front porch and steps. These are cast concrete, about 40 years old. I would appreciate any suggestions.

A. Painting concrete is seldom successful in the long run. It is a lot safer to stain concrete. You'll need to make sure the surfaces are thoroughly clean before applying any coating to them.

You can wash the porch and steps with a solution of TSP-PF, following the directions on the package. Rinse thoroughly and be aware that TSP-PF is injurious to vegetation, so take the appropriate precautions.

Q. I read your column every week. I need your advice on how to clean a retractable awning. I have tried using a product called Scotts Outdoor Cleaner with little effect. Please advise.

A. Try Oxy-Boost from Ecogeeks. You can buy it direct at www.ecogeeks.com.

Q. Two weeks ago my husband picked up new heart pine, 9-inch, tongue-and-groove flooring from a flooring mill in Vermont. The wood had been housed in an unheated warehouse with a relative humidity of 30 to 40 percent for two weeks. It was bundled without spacers, held together with steel bands.

When he arrived home, he stacked it in his heated shop, using wooden spacers provided by the mill between boards and raised the stacks above the concrete floor. Using a multimeter, he determined that the moisture level of the kiln-dried wood was below 10 percent. The relative humidity in the shop ranges between 30 and 37 percent. The forced hot air heat is maintained at 68 degrees.

Having let the flooring sit for a week, he started the process of finishing the boards with water-based Safecoat Polyureseal on all six sides prior to installation, but noticed many of the boards are cupped or crowned. Boards finished both toward the bark side and away are affected. Boards untouched by finish are affected. The moisture meter shows no elevation in moisture. Even so, we assume there must be a moisture issue. We contacted the flooring mill. They cannot account for the cupping and suggested my husband continue the finishing process to reduce chances of any additional moisture getting into the wood. Does this make sense?

Can we install the less severely cupped boards with the idea that gluing and tongue nailing them will flatten them? We know the longer a board is cupped, the less chance it will remediate.

A. Wide boards are always vulnerable to cupping, especially if they are flat grain instead of quarter-sawn.

You mention that the boards were from heartwood, but later say that the cupping occurred on the bark side and other side of the boards. That does not sound like heartwood.

Your husband did all the right things, and it should have prevented the problem, unless his moisture meter is not accurate. I wonder if one of your statements is accurate. You say that: "Boards untouched by finish are affected." Did you mean that boards untouched by finish are "UNaffected?"

That would make more sense. The proper application of a waterborne coating becomes more critical on wide boards.

The Safecoat Polyureseal application instructions are quite rigid. The product must be applied in thin coats and allowed to dry thoroughly between coats. For the base and any subsequent coats (if you plan several coats before applying the finish coat), the glossy product must be used, and the final coat must be the satin finish product. Light sanding between coats is also necessary, as any water-based product has a tendency to raise the grain of the wood.

I doubt you can straighten any cupped boards during installation. Forcing the boards is likely to cause them to crack, whether they are installed with the concave side up or down. You have several choices:

• Get new boards to replace the cupped ones.

• Rip the boards in half, which may be sufficient to make them usable.

• Kerf the concave side of the boards to be able to install them reasonably safely.

Kerfing is the action of making several saw cuts of appropriate depth on one side of a wood board to be able to straighten it or bend it.

In your case, the kerfs should be half the depth of the boards, and the proximity of the kerfs is dependent upon the depth of the cupping of the boards. If the cupping is no deeper than one-quarter inch, the kerfs may be made every inch to inch and a half in the center of the board, stopping a couple of inches from their edges, for a total of four to five kerfs.

Deeper cupping will require the kerfs to be closer to each other. Install the boards with the kerfed side down and face-nail each board with four nails on each joist, the outer nails 1-inch from the edges.

Q. You have helped many people and I'm hoping you can give me some advice. Our front cement stoop (the pad is 3 square feet) has pulled away from the house by about an inch.

I am wondering if we would be able to pour cement into the back of the pad in stages until it would be flush with the whole pad. Or is the smartest way to contact a concrete specialist?

A. You certainly can use prepackaged concrete mix available in hardware and box stores, and in building-supply houses, but you will have a lot of the mix left over, which will dry over time and be worthless.

Consider filling the small crack with gravel instead. You can buy bags of gravel of various size and color from garden-supply houses and hardware stores.

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. His book, "About the House," is available at www.upperaccess.com. His website is www.henridemarne.com. Email questions to henridemarne@gmavt.net, or mail First Aid for the Ailing House, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.

© 2016, United Feature Syndicate Inc.

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