Q: I recently learned that plywood contains formaldehyde, which I understand is a health hazard. I'm concerned the plywood panels I had installed on one wall of my bedroom might be harmful. What do you advise?
A: According to "The Healthy House," by John Bower (Lyle Stuart Inc.), a sort of bible for healthy-house advocates, most plywood is held together with formaldehyde-based glue.
The glue is also often used in particleboard, flakeboard and hardboard, which are other building materials. Particleboard, for example, is frequently used for inexpensive cabinets and other furniture.
Plywood and other products containing formaldehyde-based glues can emit traces of formaldehyde gas, an irritant to some people. Symptoms range from headaches and nausea to asthma-like reactions.
Formaldehyde outgassing by building products depends on the type of formaldehyde used, and diminishes as the products age.
About 10 years ago, some manufacturers voluntarily began reducing the amounts of formaldehyde-emitting substances in their products. Phenol formaldehyde, which is relatively low in emissions, is often used in modern plywood. Urea formaldehyde is considered the most-irritating form.
Some manufacturers also use warning labels on the backs of panel-type products containing formaldehyde.
Good ventilation can reduce the effect of formaldehyde. So can sealing the products with paint or other coatings, such as varnish. In severe cases, removal of the formaldehyde source is the best bet.
Q: I have been trying to locate special hidden hinges for my kitchen cabinets. I think they are made in Europe. Dealers I've consulted don't have the hinges and don't have any idea who does. Can you help?
A: Fully concealed hinges of the type used on European-style cabinets are available by mail from the Wood workers' Store, 21801 Industrial Blvd., Rogers, Minn. 55374; or call 800-279-4441.
These nickel-plated hinges, called Blum hinges, are screwed to the inside of the cabinet wall and the inside of the door. Several styles are available and are illustrated in the Woodworkers' Store catalog.
Q: How can we remove stains on our asbestos-cement shingles that are caused by water runoff from aluminum windows?
A: If washing the stains with a detergent-water solution won't remove them, I'd say the best bet is to repaint the shingles. It is important not to crack or crumble the shingles. Dust from asbestos-cement shingles, if breathed, can be a health hazard.
Before repainting, seal the stained areas with a stain-killing primer-sealer so the stains don't bleed through the new paint. Use a high-quality acrylic-latex paint for the finish coat.