Construction Problems: Location, Design and Technique

Location problems
Design flaws
Poor construction techniques

Location problems, design flaws, and poor construction techniques are all factors behind the increased reports of serious indoor air contamination.

Location Problems

When constructing a building, the soil on which the building is being built should be checked first to make sure it is not contaminated with organic chemicals, pesticides, natural gas, radon, or other pollutants. Some buildings and homes have indoor air problems because they are built on contaminated land. For example, the cause of some indoor air problems in Texas, Florida, and California turned out to be contaminated agricultural lands on which the homes and buildings had been erected. Homes have been built on hazardous waste sites or on soil with high levels of natural radon gas.

There may also be indoor air problems if the outdoor air is heavily contaminated. This may result from industrial or vehicular pollution. If the location cannot be changed, then special filters will need to be used so contaminated air is not brought into the building. Buildings downwind of agricultural sites, farms, certain industrial sites, and water treatment sites, regardless of air filtration, may result in unwanted odors.

A building should not be constructed over a water source, drained lakes or streams, for example. Excessive water in the soil may enter the home or building and result in high humidity and resultant mold growth.

Design Flaws

Many things can contribute to poor indoor air quality if they are not considered in the design of the building. Certain considerations and important steps include:

• What is the purpose of the building, what kind of activities are going to be going on in the building, and how many people will be working in the building? If these questions are not answered, then there may be inadequate ventilation that could cause problems in the future. Buildings must be designed to have sufficient ventilation for the activities and people expected in the building. This includes adequate amounts of outdoor air and the use of local exhaust for some activities. The ventilation systems also have to be designed to allow for occupancy growth over time. This is often neglected.

• Pay careful attention to roof design. Proper design and construction is needed to minimize moisture accumulation on the roof or chronic leakage of water into the building. Roof materials should be chosen that do not emit chemicals, especially when they experience direct sunlight over extended periods.

• The foundation should be designed and sealed appropriately to prevent water and moisture from leaking into the structure.

• Building materials should be used that will last. For example, a roof used in many European applications may last 100 to 300 years while a typical roof in the US lasts 10 to 30 years.¹

• Choose building materials that will be low-emitters of pollutants, that will be resistant to mold growth under normal use conditions, and that will not give off undesirable odors.

• Some buildings have had the design flaw of having parts of the cold-water humidifier of the ventilation system located above the ceiling panels where they are inaccessible for cleaning.

Poor Construction Techniques

Here are some examples of construction problems that have contributed to poor indoor air problems:

• In the southeast United States where it can be very humid, there have been many cases of vapor barriers being installed on the wrong side of exterior walls during construction. This leads to rapid mold growth that is often impossible to get rid of without ripping out all of the affected walls. To prevent this in a warm, humid climate, consult a building engineer to make sure that the moisture barrier is properly installed so that no condensation will occur.

• At the Tampa/Hillsborough County Public Library in Florida, there have been on-going problems with algae and mold ever since the building was first built. This included mold growing on ceiling light fixtures, and algae and mold in the air-conditioning system. Officials replaced a portion of the building's roof and waterproofed the structure but the odors kept coming back. When they finally brought in a consultant, they found that the library still had a leaky roof and that the air-conditioning system was inadequate to handle the Florida humidity. The roof was going to have to be resealed, the carpet cleaned or replaced, the air-conditioning system replaced, and a thorough overall cleaning that was expected to cost about $840,000 more due to these construction and design errors.²

• Make sure that good quality windows that are well sealed are installed. Here are two examples of problems that happened because of leaky windows:

  • In a courthouse in a small town in the San Joaquin Valley of California, more than 150 of the courthouse workers filed claims claiming injuries caused by hazardous working conditions because of an infestation of Stachybotrys. Several of these people developed serious lung disease. The problem began in the late 1980s during a remodeling of the courthouse when the windows were not sealed correctly. When it rained, water seeped in which led to the mold growth.³

  • At the Charles E. Bennett Federal Building in downtown Jacksonville Florida, almost all of the building's 1,300 windows leaked in 1988. The roof was replaced, all the windows were caulked, and still about 50 windows leak when it rains. As a result, there remain harmful levels of mold and bacteria in the building.⁴

• A major problem with construction or remodeling is that the area is not properly cleaned up afterwards or the building is reoccupied too soon. Right after the new Los Angeles Airport Courthouse opened in December 1999, dozens of employees began reporting health problems such as chronic headaches, rashes, fatigue, breathing difficulties and general malaise. Researchers concluded that the reported health problems were real and stemmed in part from leftover construction dust and the lingering smells of new paint, carpeting, and furnishings.⁵

• Building materials with unacceptable odors and off-gassing are often used. At a General Services Administration building in Silver Spring, Maryland, a concrete sub floor was so uneven that inches of floor leveler had to be used to even the floor before systems office furniture could be installed. Once spread, the floor leveler created an undesirable odor that resulted in irritation to the original building occupants. The building was vacated and soon became known as the "white elephant." Five years and millions of dollars later, a "tested and qualified" low-emitting floor material without odor was used on the floor and the building refurnished and occupied.

References

1. Levin H. Ten basic concepts for architects and other building designers: Best sustainable indoor air quality  practices in commercial buildings. Date accessed: November 2000.

2. Officials mull option for sick library building. American Libraries. February 1998;19.

3. Johnson J. Toxic mold plagues Visalia courthouse. Los Angeles Times. August 6, 2000;page 26.

4. Mattson M. Tests hint federal building 'sick'; Team to study mold, bacteria levels. The Florida Times-Union. October 31, 2000;page B-1.

5. Piccalo G. Tests blame courthouse for some illnesses. Los Angeles Times. August 28, 2000;Part B:page 1.