Q: We have a house that was built in 1995, in a neighborhood of other houses all built around the same time. Our house has a gray composition shingle roof that has developed large dark stains in many areas. Other homes in the neighborhood with gray or charcoal roofs also have it, but the ones with light-colored roofs don’t. Is it algae? If so, would zinc strips help? –Shirley L., via e-mail

A: It’s very likely that the staining is indeed some form of algae growth, and I contacted the Asphalt Roofing Manufacturers Association to confirm that this is their opinion as well.

As to how to deal with it, their recommendation is as follows: “Algae discolorations are difficult to remove from roofing surfaces, but may be lightened by applying a solution of chlorine bleach, trisodium phosphate (TSP) and water. Solutions for these ingredients may vary between shingle manufacturers and depend on the amount of discoloration. Solutions range from one cup TSP, one gallon bleach and five gallons of water, to one cup TSP and 2.5 gallons each of bleach and water.

“First, gently disperse this solution on the roofing surface. Use normal precautions for handling bleach. Be sure to apply it carefully to avoid damage to other parts of the building and its surrounding landscape. Avoid scrubbing the surface, as this friction may loosen and remove granules. If possible, always work from a ladder and/or walkboards to avoid direct contact with the roof surface. Observe all possible safety precautions when working on or near the roof. Finally, rinse the solution from the roof by gently spraying the surface with water. Be warned that this solution’s application and rinse process will make the roof surface slippery and potentially hazardous to walk on during treatment.

“High-pressure washing systems for algae removal should not be used. The effectiveness of such cleaning techniques are only temporary, and discoloration will likely recur.”

Opinion varies somewhat on the effectiveness of zinc strips, which release small amounts of zinc oxide onto the roof whenever it rains. At best, the zinc strips will help inhibit additional algae buildup, but will not prevent or kill it.

If you’d like to give them a try, first follow the recommended cleaning outlined above. Then, after the roof is completely dry, apply the zinc strips at the top of the roof, just under the ridge shingles, leaving about two inches of the metal exposed to the weather.

Q: I need to replace my deteriorated siding, which is a combination of Louisiana-Pacific’s composite lap boards and T-1-11 sheets. We do not have a very active homeowners association; however, our CC&Rs state that “all houses shall have cedar or LP siding or equivalent on the front side … T-1-11 allowed on the remaining sides.” I prefer to use vinyl siding, and was wondering if that would be considered “equivalent”? –David C., via e-mail

A: It’s always difficult to interpret the intent of CC&Rs, since so much hangs on how well they are written and how strictly they are enforced. In my experience, if the CC&Rs had intended to allow vinyl siding they would have specifically mentioned it. Since cedar and L-P are both wood or wood composites, and since T-1-11 – another siding that is found only in wood or wood-composite varieties – is specifically mentioned as well, my interpretation would be that vinyl siding is not something that would be considered “equivalent.”

If, however, you interpret the intent of the CC&Rs as being that the house should have the appearance of a lap- or board-style siding, then you might be able to make the case that vinyl siding has the equivalent appearance.

My advice would be that first of all, you check a little deeper into who, if anyone, is administering the CC&Rs — sometimes it’s the original builder, as opposed to a homeowners association — and seek clarification from them. If, as you suspect, the CC&Rs are not being enforced, you still need to remember that when you purchased the house you agreed to be bound by those restrictions, so I might also suggest that you pay for a quick consultation with an attorney to be sure you’re on solid ground.

Finally, if the CC&Rs are not being enforced and you appear to be OK legally, then I think that the final step before proceeding would be to would talk with your neighbors, strictly as a courtesy, and see if anyone has an objection to your use of vinyl siding.

Remodeling and repair questions? E-mail Paul at paul2887@ykwc.net.


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