In modular or manufactured homes that are delivered to the site in two (or three) sections, the joint where the sections of the structure are joined together is called a marriage joint. (It is sometimes also referred to as a marriage line or mating joint.) Marriage joints can be significant sources of air leakage. They should be properly gasketed and sealed to avoid leakage and maintain indoor air quality. Air leakage leads to heat loss in the winter and cooling losses in the summer.
Double-section modular homes are transported to the site as two separate sections. The marriage joints, beam joists, and walls are aligned and connected at the site. The roof, walls, and floor along the marriage line must be properly aligned, sealed, and supported.
Modular home manufacturers offer two options for delivery of manufactured homes to the home site: turn-key or rough set. With the “turn-key” option the manufacturer constructs the foundation, delivers the home, sets the home on the foundation, seals the marriage joints, and performs all finishing work. With the “rough-set” option, the home is delivered to the site by the manufacturer and placed on a foundation built by a third party (Steven Winter Associates 2001). The third-party contractor is responsible for ensuring the marriage joints are properly gasketed and air sealed.
Figure 1 - A typical two-section modular home installation on a pier and ground anchor system. The middle line between the modules is the marriage joint.
How to Air Seal the Modular Home Marriage Joint
1. Install a gasket along the entire seam of the marriage joint. If the manufacturer has already installed the gasket, ensure that each step below was performed.
a. Install the gasket to the ceiling, walls, and floor prior to joining the sections together.
b. Fold the gasket in half and fasten along the mating surface with nails or staples. Fasten at intervals of 6 inches on center (NFPA 2003).
Figure 2 - A gasket is installed along entire seam of the modular home marriage joint.
2. After the sections have been put in place and attached, air seal the entire perimeter of the gasket to the section walls, floor, and ceiling. Use an appropriate sealant such as caulk, foam, or silicon.