Q: I have the following questions regarding inside repairs for an older mobile home:
- The ceiling strips on the mobile home are loose. Do they need to be sealed? Is wallpaper better than paint?
- How do I manage the harmful effects of the formaldehyde used in wood paneling in older mobile homes?
- Do you put cheesecloth over or under the forced-air heating vents?
A: It sounds as if your mobile home needs a little tender loving care. We’ll take the ceiling and heating vent questions first and leave the formaldehyde question for the end because it’s a more complex answer.
No need to cover the heating vents with cheesecloth, or anything else for that matter. The forced-air heater should have a filter where the return air enters the combustion chamber.
Make sure to use a good-quality filter and change it regularly. For suggestions on the type of filter to use, contact a heating and air conditioning contractor.
It’s also a good idea to have the heater serviced annually. This will ensure that the required maintenance is performed, which will prolong the life of the unit and keep any warranty in effect.
Yes, the ceiling strips need to be sealed. We suggest neither paint nor wallpaper, but polyurethane. Some off-gassing of formaldehyde can be mitigated by sealing off surfaces with polyurethanes or lacquers.
Now, the formaldehyde question.
You may have heard that it was discovered that mobile homes donated to help the victims of Hurricane Katrina contained high levels of formaldehyde, prompting advisories to residents and an accelerated schedule to move residents out.
Exposure can lead to a range of symptoms and the EPA has concluded in a draft assessment that formaldehyde can be carcinogenic, though this assessment is subject to further review.
Formaldehyde is an important chemical used widely to manufacture building materials and numerous household products. It is also a byproduct of combustion and certain other natural processes. It may be present in substantial concentrations both indoors and outdoors.
Sources of formaldehyde in the home can include building materials, cigarette smoke, household products, and the use of unvented fuel-burning appliances like gas stoves or kerosene space heaters. Formaldehyde, by itself or in combination with other chemicals, serves a number of purposes in manufactured products.
In the building industry, it’s a component of glues and adhesives, and it’s used as a preservative in some paints and coating products.
In homes, the most significant sources of formaldehyde are likely to be pressed-wood products made using adhesives that contain urea-formaldehyde (UF) resins. Pressed-wood products made for indoor use include: particleboard (used as sub-flooring and shelving and in cabinetry), hardwood plywood paneling and medium-density fiberboard (used for drawer fronts, cabinets and furniture tops).
Medium-density fiberboard contains a higher resin-to-wood ratio than any other UF pressed-wood product and is generally recognized as being among the highest formaldehyde-emitting pressed-wood products.
The rate at which formaldehyde is released is increased by heat and may also depend somewhat on the humidity level. Therefore, the use of dehumidifiers and air conditioning to control humidity and to maintain a moderate temperature can help reduce formaldehyde emissions.
(Drain and clean dehumidifier collection trays frequently so that they do not become a breeding ground for microorganisms.)
Increasing the rate of ventilation in your home will also help to moderate formaldehyde levels. In other words, if the weather is good, open the windows. You might also explore getting a portable HEPA air filter to help purify the inside air.
Formaldehyde test kits may be ordered from various vendors, including Advanced Chemical Sensors Inc., a lab in Boca Raton, Fla.: www.acsbadge.com, (561) 338-3116. Cost is $39.
Chronic respiratory conditions and skin rashes, which can be symptoms of formaldehyde poisoning, may give you good reason to pursue this testing. Such a supplier also may have other strategies for reducing the formaldehyde levels in your mobile home.