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Mold removal could be a simple chore ... or a major hassle

Q. I read your columns in the Daily Herald but never keep them around. You had a column a few weeks ago about a product to remove mold.

I found mold in the basement behind paneling, which all has to go, as well as about three feet of framing. Any advice would be greatly appreciated.

Another small request: My wife wants me to paint over the varnished kitchen cabinets. What is the best sealer to apply before painting, and do I have to sand the old varnish before sealing? The cabinets have not been touched in 20 years. Enjoy reading your columns.

A. I am not sure to which column you are referring. Mold can be removed with a bleach solution or other commercial mold removers.

But, if I understand what you are describing, it sounds as if you have a very serious problem and you need professional advice and help.

A severe mold infestation on porous surfaces - wood is porous - is very difficult to eliminate; the affected wood may need to be replaced. The same would be true with drywall, but if the paneling is prefinished on both sides, you may be able to salvage it.

A mold remediation firm would be the place to call.

The varnished kitchen cabinets should first be thoroughly cleaned to remove all grease, finger oils, etc., followed by a light sanding. Then wipe them off with a tack cloth to remove all residue and prime them with B-I-N.

Paint them with a top-quality acrylic paint of your choice: high gloss for better cleaning, semi-gloss for lesser shine, or a satin finish.

Q. I enjoy reading your column in our local paper, The Daily Herald. I am wondering if you have any suggestions for a shower/bathtub caulk that will not grow mildew under it. We have tried several products. We have tried drying it out and scraping out the old stuff, then drying it some more and replacing the caulk. The mildew reappears. Any suggestions are appreciated.

A. Your shower/tub was probably caulked with regular silicone, which has a tendency to mildew and separate from surfaces over time. Unfortunately, it's a product widely used in these applications.

My favorite caulking compound is Sikaflex-1a, a polyurethane compound, which I have used in most indoor and outdoor applications since the late '50s/early '60s.

You are likely to have difficulty finding Sikaflex-1a in local stores. Home Depot carries Sikaflex Construction Sealant, which seems to be the same as Sikaflex-1a. You can also buy it online through A.H. Harris stores (www.ahharris.com), or by calling the Williston, Vermont, A.H. Harris store at (802) 860-9470. They ship at a reasonable cost.

Please keep in mind that if you use a polyurethane caulking in a bathroom, you should not get it wet for a week or it will turn pink. This presents a problem if the tub/shower is the only one you have.

An alternative is to use a caulking made for baths and kitchens that contains a mildewcide, such as DAP Kwik Seal 3.0 Advanced Caulk With Microban. It's silicone-based and advertised as mildew-proof. I have tried it on half of our tub with the other half caulked with Sikaflex-1a. The DAP Kwik Seal remained a bright white, but began to peel off in about a year. It could be that I didn't thoroughly remove all remnants of the old caulk. Sikaflex-1a lasted for years, but it will turn slightly grayish as it matures.

The most important preparation is to remove all remnants of the previous caulking, especially if it was silicone. You can remove silicone caulking by running a utility knife on each side of the caulk to peel enough to get a grip on it; it is quite easy to peel the rest of it off.

Once you have pulled off all the caulk, you need to remove any residue from the surfaces or the new caulk may not adhere for long.

You can do so with special caulk removers, such as McKanica 0351 Silicone Caulk Remover Gel by Neutraders LLC, which you can buy from Amazon. An 8 oz. cartridge will cost you under $20 including shipping.

Q. I have an All-Nighter stove insert in my fireplace. I recently spray-painted the stove with a Stove Black "high temperature" paint, and some of the overspray settled on the fieldstone at the base of the stove. How can I remove this black paint without damaging or discoloring the fieldstone?

A. I am assuming that you haven't tried any remover yet. The paint may have hardened by now and may be more difficult to remove.

Try Smart Strip, a Peel-Away product carried by Vermont Paint in Williston. Follow the directions on the container. If that does not completely remove the paint, try acetone and xylol, but not at the same time. Be sure to ventilate the area when using these products, and wear skin protection.

Q. The hardwood flooring around the toilet in our bathroom has begun to discolor. There are no signs of water on the surface of the floor. Do you think that the toilet seal would be leaking underneath the surface? Would you recommend replacing the seal, or do you think that this discoloration might be caused by something else? I really don't want to replace the toilet seal if that would not solve the problem.

A. In the photo you sent, it looks like there is a small leak at the base of the toilet coming from the toilet's wax seal. It is likely that the finished floor is not carried very close to the toilet flange. The water leaks onto the subfloor and is absorbed by the end grain of the wood, which is what shows in the photo.

The wax seal can be replaced with the newer waxless-type seal that should never need replacement.

Q. In a recent issue of the Daily Herald you addressed a question pertaining to attic venting, indicating a passive system is most efficient. I have a 25-year-old home with sufficient soffit and ridge venting, and no attic fan. What do you think about a solar-powered exhaust fan to replace one of the ridge-mounted passive vents? Also, what is the average useful life of a cedar-shake roof?

A. So instead of a full-length ridge vent, you have several passive vents. Even though this does not represent the ideal venting system, if it is working, I would not recommend changing it. Why go to the expense of buying and installing a solar-powered vent?

The ideal passive venting system consists of full-length soffit and ridge vents because they provide a complete air wash over the backside of the roof sheathing in every rafter bay. A partial passive venting system of a few scattered soffit and ridge vents does not accomplish that.

The average life of a cedar shingle roof depends on the climate. Unless the cedar shingles have been treated and are maintained regularly, you should not expect more than 12 to 15 years. Cedar shake roofs should last a few years longer.

Q. My home was built around 1942 and is a bungalow type. It has an English basement that is half below ground, half above. It is a cinder block foundation. My studding goes up to the roof with no access to the eaves. So I have no eaves venting.

I recently had a roof vent put in at the peak of the roof for the entire length of the roof. I also have a gable vent at the front of the house with a window in the back of the house gable. Is this enough venting for the roof? I would like to insulate further in the attic, but I am worried about proper venting. Since there are no eaves vents, can I insulate all the way into the corner where the roof and side walls meet?

Any information you could give me would be greatly appreciated. I also have an attic fan in the attic and don't use it because it just pulls air from the vent that runs at the top of the roof along its entire length.

I know eaves vents are crucial, but there's really no easy or practical way to do it without redoing major structural work. Thanks.

A. Your house seems to have been built with balloon framing, in which very long studs span from the foundation to the roof - common in those early days.

A continuous ridge vent performs best with matching lower vents in the soffits. But if your attic is showing no signs of moisture problems, such as icing and wet spots on the roof sheathing, you should not need to do anything more.

But it is possible, after you have added insulation, that the attic's temperature may drop considerably, which will cause the relative humidity (RH) to rise, resulting in condensation on sheathing and rafters, particularly if the attic window is closed, leaving only the opposite gable vent as an intake.

Even though you cannot provide soffit ventilation, there is a way to add low venting on your roof by using DCI's SmartVent, www.dciproducts.com. It is installed onto the roof sheathing at the appropriate spot and is covered with shingles. A slot is cut on the roof sheathing to allow the air to flow below the roof sheathing into the attic itself.

Be sure that the SmartVent is installed in such a way as to provide the air intake above the new insulation level.

But before adding insulation, stuffing it all the way to the bottom of the roof, you should install some type of baffling system so that the insulation does not come in contact with the roof sheathing. My concern is that any moisture working its way into the attic and through the insulation may condense on the roof sheathing, which may cause it to be damaged. Leaving a space as small as one inch would allow some moisture dissipation.

Baffles of various materials can be found in building-supply 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.

© 2015, United Feature Syndicate Inc.

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