Air Sealing Modular Home Marriage Joints
Marriage joints between modular home modules at all exterior boundary conditions fully sealed with gasket and foam.
- Install a gasket along the entire seam of the exterior boundary where modules are attached together.
- When modules are in place, seal the edge of the gasket to the module.
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.
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).
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.
Marriage joints between portions of modular homes should be visually checked to ensure that a gasket is installed along the entire seam of the modules and the outside portion of the gasket is fully air sealed. An experienced technician can also check for air leaks with a smoke pencil or by feeling with the back of the hand. Air barrier effectiveness is measured at the whole-house level by blower door testing, which may help indicate whether marriage joints have been successfully sealed. To ensure indoor air quality and code compliance, air sealing strategies must be accompanied by whole-house ventilation systems and local mechanical exhaust.
No climate specific information applies.
[Note: Guidance for ENERGY STAR Certified Homes Version 3.0, Revision 08 is coming soon.]
ENERGY STAR Certified Homes (Version 3.0, Revision 07), Thermal Enclosure Checklist, Air Sealing. Cracks in the building envelope fully sealed. Marriage joints between modular home modules at all exterior boundary conditions fully sealed with gasket and foam
Exhibit 1: Mandatory Requirements. Certified under ENERGY STAR Qualified Homes Version 3
The 2009 IECC does not specifically address sealing the marriage joints between modular home modules. Table 402.4.2 Air Barrier and Insulation Inspection Component Criteria, Walls: Corners, headers, narrow framing cavities, and rim joists are insulated.*
The 2009 IRC does not specifically address sealing the marriage joints between modular home modules. Table N1102.4.2 Air Barrier and Insulation Inspection, Walls: Corners, headers, narrow framing cavities, and rim joists are insulated.
The 2012 IECC does not specifically address sealing the marriage joints between modular home modules. Table R402.4.1.1 Air Barrier and Insulation Installation, Walls: Junction of foundation and wall sill plates, wall top plate and top of wall, sill plate and rim-band, and rim band and subfloor are sealed. Corners, headers, and rim joists making up the thermal envelope are insulated.*
The 2012 IRC does not specifically address sealing the marriage joints between modular home modules. Table N11402.4.1.1 Air Barrier and Insulation Installation, Walls: Junction of foundation and wall sill plates, wall top plate and top of wall, sill plate and rim-band, and rim band and subfloor are sealed. Corners, headers, and rim joists making up the thermal envelope are insulated.*
*Due to copyright restrictions, exact code text is not provided. For specific code text, refer to the applicable code.
Tight Air Sealed Home = Comprehensive Draft Protection