Surface preparation is the key to a durable paint job

Q. The town hall building adjacent to our property is an old, wood-clapboard, plastered building with an unvented slate roof sitting on a new poured-concrete foundation with a full basement. A wood frame addition was put on the house when the building was moved to its current site in the 1980s. Hot-water baseboard heat was installed in the entire building, but since there is no need to keep all of it heated, only the new section is kept warm. Drainage is good since we are in a gravel valley here. The problem is that there's peeling paint and mildew present on all sides of the building, heated and unheated alike. We have dealt with it in the past with volunteer labor and elbow grease. But everybody is tired of that, and we are looking for a better solution. The selectmen have asked me to price replacing the claps with cement siding such as Hardie board. I have used Hardie board on one job a number of years ago and have seen several buildings clad with it. But I don't know enough to say whether it is worthwhile in this case. I've looked online, and reports seem to be OK. I suppose the Hardie housewrap would be recommended to use with it. Any thoughts?A. The peeling paint and mildew may be related. Peeling paint is often due to poor preparation of the surface, such as not removing all dead wood fibers and other pollutants, too many coats of paint on an old building, flat-grain clapboards or mill glaze on new wood. Mildew is often caused by the use of linseed oil paints, or the building's exposure. Replacing the clapboards with Hardie board will only solve these two problems if an oil-based primer is applied on thoroughly clean surfaces, followed shortly thereafter by a coat of top-quality latex paint. The existing clapboards might be salvaged by removing all their paint and starting from scratch on bare wood. But this may not be the least expensive way to go. Since you are a builder, you could price the job both ways and present that to the selectmen.In 1996, we put a two-section roof and gutters on our home. It was white and beautiful. A few years later the roof had black streaks. We called our contractor, and he came to inspect the roof but could not come up with an answer. It has gotten worse and looks terrible. We are concerned about the possibility of bleach ruining our new siding. We were wondering if you have an opinion on Roof Reviver or can offer a better solution.A. Although Roof Reviver claims great results, the process seems to be somewhat cumbersome despite the manufacturer's claims to the contrary. They recommend spraying two coats of the product, repeating every 60 days until desired and leaving nature to take care of the foam on the roof. If you need faster results, you can use their four-nozzle water rake attached to a pressure-washer and wash the foam off. But that requires walking on the roof. Despite the fact that the person on the roof in their video seems to be wearing a safety harness, I am completely against this process, as most homeowners are unlikely to own a safety harness. It is dangerous for anyone but the most experienced to walk on a roof that has any pitch above 3-in-12 inches, and even then, I would discourage it. A simpler product to use is Deck Patio Cleaner by Pacific Sands. Go to ecogeeks.com; click on Exterior Products and on "Exterior PROx Nontoxic Deck Patio Cleaner." Although it does not mention that it can be used on roofs to remove algae, it does so very successfully. Pour 3/4 cup of the powder in a gallon of hot water and spray it on the shingles at the rate of one gallon per 50 square feet, using a pump-up sprayer from a ladder on a very calm day. Leave the solution on for approximately one hour and rinse it off with your garden hose. The manufacturer claims that Deck Patio Cleaner is harmless to vegetation and metal gutters. I have mentioned several methods of cleaning algae off roof shingles. Unfortunately, space does not permit me to repeat every one of these methods every time the question is asked. Look in previous columns for more suggestions.We own a Cape-style home. The first floor has an open concept. One half is the living room, and the center has a staircase leading upstairs and a staircase leading to the basement. The other half of the house is the kitchen and dining room. The wall at the front of the house extends from the living room side all the way into the dining room. The center wall extends from the living room down a hallway into the kitchen. Essentially, all the rooms are connected by common walls. We have lived here for six years with white contractor walls and no idea how to choose paint colors so that the entire house doesn't look the same. Help! A. Many well-stocked paint stores either have an experienced decorator on staff or can recommend one who can come to your home and help you with the selection of different colors to emphasize separate areas.I have 21-year-old High-Performance Andersen double-hung windows. Are the new windows sold today efficient enough to warrant replacement?A. I don't think it makes much sense to replace High-Performance Andersen windows with today's more efficient windows. It would take you a very long time to recoup the initial investment. If your current windows are not equipped with Andersen storm panels, this is the way I suggest you go.I have had a squeak upstairs in my house for months, and I can't seem to locate where it is coming from. It sounds like a little chirp from the smoke detector, but I pulled the batteries out of that. The chirp still happens about every minute. Someone thought it might be water leaking. Do you have any ideas where I might look to stop it?A. I hope you put the batteries back in the smoke detector! The fact that the chirp is heard about every minute or so would indicate that it is coming from a device that depends on a battery to function. If you have a carbon monoxide detector, check the batteries. I doubt very much that it is from a water leak, which would make more of a plopping sound. Try to zero in on the sound by listening when everything in the house is very quiet.A recent column mentioned using Tang as a toilet bowl cleaner. I bought the Tang, but lost the article, so I can't recall the amount you suggested using. Can you please send me the details? As you can imagine, I find your column always interesting, frequently useful, and reliably easy to understand.A. Slowly pour a full can or 3/4 cup of Tang powder into the toilet bowl and leave it overnight.Foam guys seem to push spraying the foam on the underside of the roof and eliminating all venting. They refer to this as a "conditioned" attic. It would make sense if one had HVAC equipment in the attic, but I don't know if that would be best in our area, climate zone five. Builders and furnace/AC people that have worked on my house do not favor this approach. What do you think?A. You are correct. I, too, do not recommend foaming the underside of a roof in a standard attic, unless it houses the air-conditioning system or is to be converted into living space. However, closed-cell sprayed foam is probably the best way to insulate cathedral ceilings, since they are so difficult to protect from moisture-laden warm air convection and to ventilate effectively.A recent column of yours addressed a problem we have with moisture wicking up from the ground onto our patio slab. This problem occurs mainly during rainy seasons of the year and causes a sheet of water to cover the patio floor. Our patio is roofed and screened, and we have a real tough time using it during these wet seasons. I am pretty sure that the concrete was poured directly over soil and not over stone with a moisture barrier - however the slab itself is in great shape. There are a few pits but no cracks. The floor has been painted a number of times, and the paint always chips off. What can be done to minimize the wet issue? Can we install a brick floor or a floating-tile floor? The info in your column suggests that we also might be smart to address the wooden-roof supports, which do not seem to be a problem. A. I assume that you only use your patio during milder weather, and not in the winter or cold spring and fall days. In this case, the moisture problem on the porch floor occurring during rainy periods may be caused by very high humidity in the air condensing on a cold slab. If the concrete slab was poured directly onto the soil, without a stone bed and vapor retarder membrane, it is more likely to be at the temperature of the substrate and remain relatively cool. If this is the case, adding bricks may help to the extent that they will absorb the moisture, but they must be somewhat porous and not hard-burned pavers. A tile floor would act very much as the concrete does and not be helpful. If condensation is the problem, an outdoor carpet may take care of it. In my answer to the other reader's question, I suggested checking the supporting posts because he or she mentioned that the gyp board covering them was wet - an unhealthy situation. You may not have that problem. bull; Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.#169; 2009, United Feature Syndicate Inc.