Mildew thriving above shower, on walls, ceiling
Q. I have black spots on the ceiling of my bathroom and wondered what they are and how to get rid of them. They are mostly on the perimeter of the ceiling above the bathtub and shower area. I have noticed they are spreading and getting worse. I want to nip them in the bud now before they get too out of hand. What do you suggest? Also, afterward, I want to repaint the ceiling. Any suggestions on what kind of paint I should use? I live in Illinois and read your column in the Daily Herald.
Via e-mail
A. The black spots are mildew. Mildew develops because the high humidity in the bathroom does not dry fast enough for lack of ventilation. The mildew occurs around the perimeter of the ceiling because it is where the air is most stagnant. Wash the affected areas with a mixture of equal parts fresh Clorox bleach and warm water and let dry. Paint the ceiling with Zinsser's Perma-White, a paint containing mildewcide and guaranteed for five years against mildew formation. You should also increase the ventilation in the bathroom by using a fan during and after showers. Install one if you don't have one and it is feasible to do so. You can also open the bathroom door after showering and leave it open. Or, if there is a window, crack it open for a while with the door closed in winter.
Q. My ranch needs new siding this spring. I am concerned about which siding and insulation method to use. One choice is to have the vinyl siding placed over ½-inch foam insulation and Tyvek housewrap. The alternative is to have foam-backed vinyl siding over Tyvek housewrap. This foam-backed vinyl siding is supposed to offer more resistance to dings and cracks. It is offered in two different ways, depending upon which manufacturer I use. The foam can either be free-floating on the back of the vinyl siding or glued to it.
Can you advise me as to which of these three choices would be the best to provide insulation for my house and protect the vinyl from cracks and dents? I am planning on living in this house for another 20 years or more, which makes my decision important to me. Your advice would be greatly appreciated.
Bridgewater, N.J.
A. You didn't say, but am I to assume that you will remove the existing siding? And what is it made of? Considering the increasing cost of heating homes, regardless of which fuel is used, my recommendation would be to use 1-inch-thick XPS (extruded polystyrene) rigid foam instead of ½ inch. That may raise the cost beyond what you are willing to pay, although you would recoup the original investment over time.
If this is the way you choose to go, the housewrap should be installed directly onto the sheathing, and the rigid insulation should be applied over it. Depending on the type and condition of the present siding, you may not need to remove it. Vinyl siding with integral EPS (expanded polystyrene, which is not as good as XPS) is said to make the siding more resistant to dents -- not cracks, but is it important to you? Do you live in a neighborhood where this may be an advantage? Do you have young children? Vinyl siding with integral foam insulation is likely to be more resistant to denting than one with the free-floating foam, as there still could be a small space between the insulation and the foam unless the installers are very careful.
All in all, the quality of the installation is most important, as most vinyl-siding products from well-established manufacturers are of high quality.
Q. My mother owns a home on the Northwest side of Chicago. Her house was dormed out in the 1970s. The home has water damage to the walls of the main level along the front of the house. In winter, the home has damming problems. I believe that the home was never properly insulated. She has had a new roof and flashing installed. This did not fix her problem. Can you suggest someone to contact that could be of some help?
Via e-mail
A. Contact a professional engineer or a licensed and certified home inspector. Look in your Yellow Pages under "Engineers-Consulting" or "Engineers-Professional." Also, look under "Home & Building Inspections"; there you should find a list of ASHI (American Society of Home Inspectors) Certified Inspectors. Any of these professionals should be able to figure out the problem and offer solutions.
If the dormer is on the front of the house, it sounds like melting snow, backing up behind ice dams at the eaves, is getting under the roof covering and running down the dormer walls, flowing into the main level walls. If the roof of the dormer is shallow (less than 4-in-12 pitch), and asphalt shingles were used without an underlay of Ice & Water Shield (or equivalent), the leakage is no surprise. Shallow roofs should be covered with a synthetic rubber membrane.
© 2008, United Feature Syndicate, Inc.