'Miss Muffet' strikes back against eight-legged pests

Q. We have lots of spiders on the outside of our house. Every day there are new cobwebs on the house. A friend of ours told us that he used a special spray on the outside of his house, and it kept the spiders off for the summer. Unfortunately, he could not remember what the spray was. He said that he mixed it up and applied it with a garden sprayer. Do you know what this may have been?

A. Try Miss Muffet's Revenge Spider Control, a spray product available in many hardware stores, Lowe's and some building-supply houses. Miss Muffet's Revenge claims to be effective for a year, indoors or out.

You can see details and also buy it online at www.wetandforget.com.

Q. We read your column regularly and greatly admire the extent of your knowledge and your sensible suggestions. We have a question now: How can we safely rid the outside back of our toilet tank of what appears to be black mold? Because there is only about 1 inch between the tank and the wallboard, it is difficult to get a good look, but when brushed off at the sides where it is reachable, a black powdery substance comes off.

A. The mold is likely to have developed because, in the summer, condensation forms on the outside of the toilet tank in a poorly ventilated space when cold water refills the toilet tank after each flush, especially if you have well water.

One inch is enough space for you to tack or staple a piece of toweling to a 1-inch by 2-, 3- or 4-inch stick long enough to reach the entire back of the tank (one inch wood is only five-eighths of an inch thick). Tape a piece of plastic to the wall and cover the floor to protect them both from the treatment.

Wet the toweling with a mixture of one part bleach to three parts water and rub the back of the tank with it. You may need to clean the toweling several times to complete the job.

If your toilet tank is not insulated, you may want to consider buying and installing an insulation kit, which you can buy in hardware stores and home centers.

Another option is to replace the toilet with a new low-flush model if yours is an old, water-wasting one. Or, if there is an electric plug nearby, you can set a small fan to circulate air behind the toilet in the summer.

Q. What is the name of the primer that covers stains on old brick in a basement? Also, what degree of grading of the soil against the house is needed to prevent water from coming in the basement?

A. No primer or other coating is going to stick to a surface that is not absolutely clean. So what is the condition of the bricks? And what stains are on the bricks? If you are referring to efflorescence - most likely if moisture is present from poor grading - it can simply be removed with a stiff brush.

Once the bricks have been thoroughly cleaned, you may not need to apply a coating on them, and any coating - paint or other - may not stick if moisture is still coming through the bricks.

My recommendation for proper grading is 2 inches per horizontal foot. But soil should not be closer than 6 inches from non-treated wood, so other alterations may be necessary.

Once you are sure that the moisture condition has been taken care of, and the bricks are thoroughly dry, you may apply a quality masonry paint, which I do not recommend because it would prevent the bricks from drying to the inside, if need be. It could eventually cause them to spall and deteriorate.

Q. Thank you for your response to my previous question about cleaning algae from my roof. After I would spray on the bleach/water solution, do I leave it on and let Mother Nature take it off by rain, or use a low-pressure power-washer after the solution has soaked in for, say, 30 to 45 minutes? Also, my roof is 19 years old; the shingles are IKO Cambridge Ultra Shadow with a 25-year warranty. I live in northeastern Vermont and do not have overhanging trees on the house, but do have them on the southern end of the house about 30 to 40 feet away.

A. Once you have sprayed the shingles with a bleach and water solution according to the recommendations I sent you, and used all the necessary safety precautions, do not rinse the shingles. Let the solution stay on, but be prepared for a long wait before you see results.

You can also install a zinc strip just below the ridge cap to keep the shingles clean. Power-washers should not be used on asphalt or fiberglass shingle roofs; the risk of dislodging the protective mineral granules is too great.

Q. My problem is in regard to my overhead garage door. The concrete under which the door closes is chipping a good deal, which prevents the door from securely closing. This allows spaces in which cold air enters the garage.

What advice would you offer in order to repair the concrete to ensure a tight seal?

A. There are many concrete repair products available in hardware and big-box stores and building-supply houses: Thorocrete, Sakrete, Quikcrete and Sika are some brand names.

Q. In a Daily Herald column last month, your answer to the person asking about the cost-benefit comparison of emulsion (water based) and oil-based asphalt sealers was interesting and probably accurate.

Unfortunately, you did not mention the most important factor that people should consider in their sealant selection - namely the environmental factor. As much research data have pointed out, significant harm is being done by the oil-based materials to our rivers and streams because of runoff. Most eco-conscious consumers among private property owners, municipalities and commercial ventures have now switched to green products, such as emulsion sealants.

A. True, I did not include that in my answer because I reprinted verbatim the response to my question of my old friend, an expert in all aspects of these matters.

His answer was clear: "I didn't know that anyone still used the oil-based (solvent) sealers anymore. They are not as available as in the past, and the price has risen substantially with the price of oil. My question would be, why apply a sealer to fresh asphalt when the protective oils are still in it? That is what you are allowing to evaporate over the couple of years that you leave it to cure."

The asphalt has oil already, and that is part of the process. It does not solve the environmental question you bring up with the use of an oil-based sealant.

Q. I read your column and find a lot of useful ideas. We have a paver front walk and porch. Those darn little chipmunks go under the porch and lower the walk next to it. I have fixed it several times, but they keep coming back. Do you have any suggestions on how to keep them from going under the porch?

A. Not knowing the physical layout of the porch and front walk, all I can suggest is that you explore the possibility of installing some metal screening with a small enough mesh to keep them out, such as hardware cloth.

Another way is to trap them in a Havahart trap and relocate them to a wooded area far away from your house. I had to do that several years ago because of the damage chipmunks were causing around our house. To my astonishment, I kept catching them until 12 chipmunks were moved to a nearby forest. I had no idea there were so many, as they all looked alike to me.

Q. I was wondering if you have any suggestions on how to figure out how mice/small animals are getting into our house. We have a room in our basement that has always had an "off odor." We sometimes hear an animal scratching within our walls, followed a few days later by a terrible odor, which we assume is from the animal having died. Any suggestions on where/how to check our basement before calling someone?

A. Mice and shrews can get through the tiniest crack. I once saw a mouse come through a hole in a baseboard joint that was only a quarter of an inch.

You will need to check every inch of your home's exterior with a fine-tooth comb and seal every hole with regular caulking, spray foam, stainless steel wool, or a specially made product for excluding small rodents called The Xcluder, which you can check out and order at www.buyxcluder.com.

Or have a local, family-owned pest control firm do the job for you, but make sure that you have a written guarantee that, if necessary, they will come back until the problem is completely solved.

Q. I read in your column not to use steam cleaning on wood floors. My kitchen has a laminated floor - is it OK to steam clean it?

A. I do not know of anyone in the flooring industry who would recommend it. It's too risky.

An Eco mop is best.

Interesting comment: "Have you considered use of aluminum oxide as a better slip-resistant product for coating concrete surfaces, whether they be steps, decks or walkways?

"I have been in the floor-coating industry for 30 years, and this product holds up better than silica sand and does not turn black like silica. You can find this product at Sherwin-Williams under the name of Shark's Grip or at builders supply stores that have concrete repair materials."

My take: Thank you for this great tip. I was not aware of aluminum oxide as a slip-resistant material.

• 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 and in bookstores. His website is www.henridemarne.com. Email him at henridemarne@gmavt.net.

© 2014, United Feature Syndicate Inc.