Condensation Control

The condensation process occurs when warmer moist air comes in contact with cold surfaces such as framing members, windows and other thermally conductive accessories, or the colder region within the insulation itself (if moisture has penetrated the vapor retarder). Warm air, having the ability to contain more moisture than cold air, loses that ability when it comes in contact with cooler surfaces or regions. When this happens, excessive moisture in the air is released in the form of condensation. If this moisture collects in the insulation, the insulating value is decreased.

In dealing with condensation, air may be considered to be a mixture of two gases-dry air and water vapor. One thousand cubic feet of air at 75°F can hold up to 1.4 pints of water. At 45°F, it can hold only 0.5 pints.

Relative Humidity is a percentage measurement of the amount of water vapor present in the air in relation to the amount it is capable of holding at that temperature. Therefore, 50% Relative Humidity would mean that the air is carrying only one-half of the total amount of moisture that it could be holding at that particular temperature. Cold outside air is usually much drier than warm inside air. Therefore, you can lower the Relative Humidity by bringing in outside air to mix with and dilute the moist inside air. At 100% Relative Humidity, the air is "saturated."

The temperature at which the air is saturated and can no longer hold additional moisture is called the dew point temperature. Whenever air temperature drops below its dew point, excess moisture will be released in the form of condensation. Condensation problems are most likely to occur in climates where temperatures frequently dip to 35°F or colder over an extended period of time.

Ridge Vent

Ridge vents come completely assembled for ease of installation. Ridge vents supplied by Metal Building Depot are of a low profile design to provide gravity type ventilation. Because gravity ridge vents are designed to allow free airflow, some penetration of water during blowing rains is to be expected. Standard available finishes for the ridge vents are polar white and galvalume. Other colors may be available at an additional cost. Nominal ridge vent length is 10'-0". Ridge vents are available with 9" and 12" throats. Bird screens are provided as a standard. The ridge vents can be ordered as continuous or single units. Exterior parts are 26 gage painted or galvalume. Interior parts are all made of G90 galvanized steel. The substructure consists of 10 gage saddle straps with interior baffles of 24 gage steel. Lifter arms and damper slides are made of 18 gage steel. Manual operation is through activation of a pull bar which is attached internally to bell cranked type lifter arms connected to the damper with Teflon coated pins through the damper slides. Dampers are spring loaded to remain in the open position until the pull bar is operated and locked in the closed position. Dampers operate in a vertical manner. Each vent is opened by a pull chain that extends approximately 12" below the roof unless noted otherwise on the order documents. Other opening mechanisms are available at an additional cost upon special request. Ridge vents should not be placed closer than 5’-0" to the endwall steel line to allow room to properly flash the building. For example, a 90’-0" long building with ridge vents required the entire length should have no more than (8) units. The ridge vents are available with the following accessories:

Sheeting

All sheeting is 26-gauge "R" panel. Color sheeting has a galvanized substrate to prevent rust and corrosion. All our Galvalume roof sheeting is hot dipped with a zinc and Aluminum compound to give it the strength to stand up to the worst weather, and the durability to last for generations.

Panel Options

Color or Galvalume - Our online system includes both Galvalume Plus® and SMP Colors. For a small price increase you can add a colored roof. Our standard colored panels consist of a Galvalume® sheet that has been primed and coated with Silicon Modified Polyester (SMP) paint. Both panel types of panel are very tough, and both our Galvalume Plus® warranty and our paint warranty run for 25 and 30 years respectively. The Galvalume Plus® panels cost less, but the painted panels give your steel building a more refined look.

Color and Roof Pitch - When considering color over Galvalume, be sure to take the roof pitch into account. Higher-pitched roofs are more noticeable, but with a low-pitched roof very little of the roof can be seen.

Panel Profiles

Roof Panel Profiles - Our standard roof sheeting is the "PBR" panel, which is available in bare Galvalume Plus® as well as a variety of colors. Wall sheeting is available in "R" and "PBR" panel. Depending on the color and your geographic location - PBR panels may not be available for certain colors.

Liner Panels - For liner panels we offer a low-rib 29-gauge panel. Liner panels are an interior covering for the walls of a steel building. Like exterior walls, liner panel consists of 3-foot wide panels that are attached to the framing in the same manner as exterior sheeting. Full-height liners run from floor to roof. Partial-height liners typically attach to the girt at 7'4" and extend a few inches above it. Buildings with liner panels must have a base connection for the bottom of the panel (see base conditions).

Advantages - Liner Panels enhance appearance, providing a finished look for the interior. The biggest advantage is that liners protect the insulation and the outside walls. Because un-reinforced insulation facings tear easily, and even the best-reinforced materials can be damaged, liner panels are the intelligent solution to protect your investment. Although 26-gauge exterior walls can withstand a lot of punishment, a steel liner will protect your building's interior and performs at a lower cost than other wall coverings, which will require their own framing.