clock menu more-arrow no yes

Filed under:

Proper ventilation of the attic a bigger issue than roof color

Question - How important is roof color in keeping the house cool? My roofer tells me that the color of roof shingles doesn't matter because the ridge vent will cool the attic. Louise Betts, Speedway, Ind.

Answer - Your roofer is right, at least in northern climes (say, north of the Mason-Dixon line). It's true that a white roof will reflect heat and a black one will absorb it. Just walk barefoot on a beach on a hot summer day; it is tolerable on sand, but you can hurt your feet on a black asphalt surface.

No matter what the color of your roof, ventilation of the attic is important. An attic with a ridge vent and soffit vents (at the eaves) will keep an attic no more than 10 degees warmer than outdoors. If you have enough ventilation in the attic to keep it from collecting moisture in winter, it is enough to keep the attic temperature relatively cool.

As for esthetics, the handyman feels that dark-colored roofs look much better than light-colored ones. Take a look around your neighborhood. And a dark roof is less likely to show dirt or mildew.

Question - I have not yet moved into a house I bought, and my problem is that there is a lot of mold growing in the kitchen and dining room, on the floors and on the cabinets, even on the carpet in the kitchen. The house is on a slab and the rooms affected are on the north side of the house. I'd like to know what's causing the mold and how to get rid of it. I have kept the windows open since I bought the house, but there is no change. Mickey Wilson, Wichita, Kans.

Answer - What causes the mold to grow is moisture. Becuase you have kept the windows open, I assume the house had been closed up for some time before you bought it. The closing up of the house created a buildup of moisture (water vapor) that condensed on cool surfaces. The mold appeared in the rooms on the north side of the house because those rooms are shaded and cooler than the rest of the house, and water vapor condenses on cool surfaces.

To get rid of it, wash areas affected with a solution of 1 part liquid chlorine bleach and 3 parts water. Wear skin and eye protection when working with bleach.

To keep mold away, keep ventilating the house. And use a dehumidifier on particularly humid days.

As for the kitchen carpet, the bleach and water treatment could bleach the rug, something you want to avoid. So, make the solution 1 to 5 or 1 to 7 or so, and try it on an obscure area of the rug to make sure it does not bleach. Also, pick up a corner of the rug to see what's under it. There may be moisture trapped underneath. If the rug is wet and black with mold, throw it away; it is trapping moisture coming up through the slab and will continue to do so. Replace the rug with ceramic tile or an indoor-outdoor carpet that will allow water vapor to pass through it.

Mold and its problems have been discussed many times in this column, but the reason it appears here now is that the writer omitted his address; otherwise, the question would have been answered personally.

Question - I have had five estimates on replacing my concrete driveway. The present one, with no gravel under it, is breaking up badly.

Two contractors suggested breaking up the concrete and taking it away, excavating several inches and installing crushed stone under the new concrete. Others said to take away the old concrete and pour new concrete on the ground. Some suggested 5 inches of concrete, with reinforcing mesh wire; others said 6 inches without wire. Now I'm all confused. What will work best? Jean Wal-kauskas, Bradford, Mass.

Answer - In as few words as possible: 6 inches, with mesh, on 6 inches of crushed stone is best. The old driveway broke up mainly because it was laid on the ground, providing no drainage at all. Any concrete driveway will be expensive, but I offer one more point: Install the driveway in 10- to 15-foot increments, divided by expansion joints, which will make the driveway resistant to cracking.

Question - I am replacing deck boards that are not pressure-treated; the joist and other parts of the framework are. How far apart should the boards be? How far apart should the boards be end to end? Gerald Martin, Dorchester, Mass.

Answer - Space the boards 1/4 to 3/8 inch. I think 3/8 is better because when they swell with moisture, the boards will not close the gap. With 1/4-inch gaps, this is possible. For boards meeting end to end, spacing of 1/8 inch is enough.