Mothballing

The goal of mothballing is not to fix the building, but to keep it from deteriorating while it is not being used. Once the building has been stabilized, turn your attention to specific areas that need to be dealt with when mothballing the building, including:

• Ventilation
• Windows and doors
• Chimneys
• Exterior
• Plumbing and radiators
• Building site and adjacent features
• Building security

Ventilation

Adequate air exchange reduces unwanted moisture from condensation. The goal is to provide a minimum of one to four exchanges every hour. The exact number varies by season with one to two exchanges per hour needed in winter and two to four in summer (Park 1993).

Determining the exact number of air exchanges for a particular building and identifying how to achieve them depend on the type of building, its age and condition, its fixtures, and the climate. While each case must be evaluated individually, the NPS has identified some rules of thumb. These rules (table 1) illustrate the factors that combine to influence decisions about ventilation.

The ventilation system should be designed so that air can enter at ground level and leave at roof level. Cross ventilation in the attic as well as louvered window inserts can help achieve this type of air exchange (figures 7a and 7b).

If possible, chimneys should remain open. They can help air flow from lower levels to upper areas of the building. If the building has power, fans can be put in the chimney to encourage this airflow.

Figure 7a—Louvered window ventilation inserts on the Bonita Work
Center bunkhouse, Lolo National Forest, MT (outside view).

Figure 7b—Louvered window ventilation inserts on the Bonita Work
Center bunkhouse, Lolo National Forest, MT (inside view).

Louvers should be constructed so that wind and weather can't enter. As a general rule, if the angles of the louvers are such that you cannot look through them, snow and rain are less likely to blow in. Also, in humid areas such as the Southeast, louvered window vents should be made of treated material to prevent deterioration.

The condition of doors and other closures affects how tightly the building seals and how well air enters and leaves. Furniture, equipment, or trash left in the building impedes airflow.

Floor coverings are an especially important consideration for ventilation. Linoleum or carpets (particularly rubber-backed carpets) restrict airflow from subfloor spaces, which can contribute to decay of floor timbers. Similarly, linoleum creates an impermeable layer that blocks the movement of air through the building.

At the least, fitted floor coverings should be rolled back from external walls (figure 8). Also any garbage, furniture, or other equipment should be removed. Keeping cupboards and drawers open also helps improve airflow (figure 9).

Figure 8—Pulling back carpets from floors can encourage airflow
in the building.

Figure 9—Leaving drawers and cupboards open can encourage
airflow in the building.

Windows and Doors

Doors and other first floor entrances should be closed off and locked. If window vents are not needed for the building, first floor windows should be closed off as well.

All entrances except one door used for periodic access should be sealed. Heavy plywood can be used to block doors. These entrances also could be barricaded from the inside.

Exterior

Treatments to the exterior of the building should focus on protecting wood surfaces and preventing openings that can let in pests and moisture. Maintaining the building's exterior also increases the structure's security. Buildings that don't look like they have been abandoned might be less attractive targets for vandals.

To mothball the building's exterior:

• Paint wood surfaces.
• Repair and stabilize severe rot problems.
• Block any unwanted openings.
• Maintain measures for pest control.
• Repair any loose masonry.

Older buildings may have lead-based paint. For example, lead-based paint was deteriorating at the Bonita Work Center bunkhouse (figure 10) when the bunkhouse was mothballed. In such cases, the facility manager's task should be to remove and secure the old paint and to repaint the structure. The tech tip "Lead-Based Paint: Planning Your Paint Removal Project" (Beckley and Groenier 2007) can help facility managers address concerns about lead-based paint.

Figure 10—Damaged and flaking lead paint on the Bonita Work Center
bunkhouse, Lolo National Forest, MT (outside view).

Plumbing and Utilities

The type and extent of plumbing and utility work required for mothballing depends on the systems left in service after the building is closed. The NPS recommends, "As long as these services will not constitute a fire hazard, it is advisable to retain those which will help protect the property" (Park 1993). Electricity, for example, can power ventilation fans and timed lights for security. Natural gas, water, and electricity may be used for heating.

If plumbing fixtures are not going to be kept in service, turn off the water supply and drain the pipes, toilets, water heaters, and any other water reservoirs. Disconnecting taps and plugging the plumbing to sinks and other fixtures are good practices. Removing toilets and plugging up the drains will discourage anyone from using them (figure 11).

Have the utility company turn off the natural gas lines if gas is not needed. The gas meter can be removed and gas lines can be plugged.

Oil furnaces require additional considerations. You may wish to fill the fuel tank with oil to keep it from rusting. Leaving the fuel tank full may not be practical. But if the tank is drained and left empty for more than a year, condensed moisture will cause rust, probably making the tank unusable.

Figure 11—Toilets were removed from bathroom stalls and the drains were
plugged in the Bonita Work Center bunkhouse, Lolo National Forest, MT.

Building Site and Adjacent Features

The condition of the building site has implications both for maintaining the structure's condition and for its security. Brush, debris, unkempt outbuildings, or improperly stored equipment can pose fire risks, particularly if the structure is in the wildland-urban interface.

Brush should be cleared so that the building can be seen by neighbors and from the street. Hidden buildings are tempting to vandals and encourage unauthorized entry and occupation.

Having a site that is open and visible also helps with personal safety. Employees are safer when they walk onto a site with good visibility.

Building Security

Looks do make a difference. A neat exterior sends the message that the building isn't abandoned, that it receives regular maintenance, and that someone is likely to notice what happens at the site. Because security options requiring power are often impractical at remote mothballed buildings, appearance may be one of the best tools (besides locks) for securing the facility.

Specifics about appearance and security depend on geographic location, type of vegetation, and the nature of mothballing work needed for the facility. However, Frazier Associates (2002) offers some general observations about using appearance as a security measure:

• Use consistent materials to avoid a patchwork look.
• Paint plywood to make it less obvious that the building is closed up.
• Use colors that match the building.
• Maintain the grounds.

A sign explaining the mothballing project can help reinforce the message that the building isn't abandoned. The sign can explain what is being done with the property, why it has been mothballed, and the options for further use. The sign should be dated so the reader knows the information is current. The sign can help people know that the Forest Service has not simply walked away from the building, that it isn't abandoned, and that it is not ripe for vandalism.

Another potential security measure that does not require electrical power is keeping watch on the property. Neighbors, law enforcement officers, and employees at nearby sites may be able to observe activity at the mothballed facility.