Q. 1. When applying joint compound, I end up with small holes. What is wrong with my technique or the joint compound? 2. In your Nov. 18 column, you stated that in northern areas, black or light-colored shingles will not affect the house (I suspect you meant the temperature on the top floor). However, in southern climes, light-colored shingles help reflect heat. What makes this difference? I now have dark-colored shingles on my house in New England.