Controlling Condensation

Two things must be present for condensation to occur: warm moist air and cool surface temperatures below the dew point. The proper control of these two factors can minimize condensation.

In metal buildings, we are concerned with two different areas or locations: visible condensation which occurs on exposed surfaces below dew point temperatures, and concealed condensation which occurs when moisture has passed through the vapor retarder and into interior roof and/or wall cavities and then condenses on a surface below dew point temperature.

Base Condition

Every metal building has some type of base connection along the building perimeter, allowing the connection of sheeting. This "base condition" determines exactly how the panels connect to the foundation. To prevent water and pests from entering the building at the base, panels extend below the finished floor of the building. Online design and pricing systems allows users to choose from a number of different base options.

Standard Base Angle - Our system defaults to a standard base angle condition. This condition consists of a single angle member, attached to both the wall sheets and the slab. Please note that the standard base condition requires that the slab be formed with a 1½" sheet notch to allow the sheets to extend below the top of the slab.

Deluxe Trim - Deluxe base trim is another option for buildings with concrete slab foundations. Deluxe base trim combines base angle and trim into one piece, providing all the benefits of base trim and base angle. Deluxe base trim is only available in burnished slate color.

Base Girt - The base girt option is designed for buildings that sit on piers rather than a full slab. A base girt system does not rest on or attach to the foundation. The base girt attaches to clips on the columns about 6" above the foundation. The base girt provides a great connection for liner panel.

Base Channel - The Base channel is a "cee" shaped section that runs the perimeter of the building connected to the floor. It is most commonly used when a liner panel, or interior wall, is going to be installed. The "cee" section provides a pre-positioned connection point for inside panels. This approach requires a sheet notch in the slab (for an alternative, see the combination of base channel and base trim below).

Installation and Selection of Insulation

We provide the highest quality products available. However, proper installation and selection is imperative for maximum effectiveness. Please refer to installation instructions to ensure correct procedures are used. Facings that have been torn or punctured are no longer capable of blocking water vapor and may eventually do more harm than good. Be sure to quickly patch any holes in the vapor barrier.

When selecting a facing, special consideration should be given to its reflective quality. A facing with high reflectivity reduces the need for high light levels in work areas. This results in reduced energy costs and increased productivity.

Although the fiberglass insulation itself is not affected by cold weather, the facing is. Colder temperatures can cause cold crack, a situation where the facing becomes brittle and if handled can crack. Bay Insulation recommends that vinyl faced fiberglass products never be installed in temperatures below 40 degrees.

Recommended Installation Methods of Insulation

Roof insulation rolls are cut to lengths that will cover the distance from eave to eave, leaving a one-foot overhang on each side of the building.

1) Start at the end of the building and temporarily secure one end of the roll by attaching the insulation to the eave strut with double-faced tape.

2) Pull the insulation across the purlins with the vapor barrier toward the building interior. Double-faced tape attached to the opposite end of the insulation will keep tension on the roof roll while the metal panels are being attached over the insulation.

3) Install the next roll in the same manner, making sure the rolls are stretched tight, aligned properly and closely butted.

4) Fasten tabs using one of the methods described on the following page. Any rips or tears must be covered with matching facing tape to ensure a tight vapor seal.

5) Trim excess insulation flush to prevent it from acting as a wick and moving water into the building.

Facings

In addition to acting as a decorative protection barrier, facings serve an integral part of the overall insulation system. Facings provide vapor barriers, light reflectivity and structural strength. In some cases, a reinforcement of fiberglass scrim is used for extra rigidity and greater impact resistance.

The effectiveness of a vapor barrier depends on three primary factors:

1) Location within the insulated section

2) Permeance

3) Proper installation