If you own a mobile home or are planning on buying one, you must know what is a marriage line in a mobile home. It is a crucial factor when evaluating a mobile home that you should never underestimate. 

Marriage line is the area of your mobile home or manufactured home where additional sections are connected. It is crucial to make sure the marriage line is sealed correctly. Otherwise, moisture and air leaking through the line can cause damage to your home. 

But why is the marriage line so crucial in a double-wide? What are the most important things to know about the marriage line? 

Let’s discuss. 

What is a Marriage Line in a Mobile Home?

In modular or manufactured homes delivered to the site in more than one section, the line where the structure sections are connected is called a marriage line. (Also referred to as a marriage joint or mating joint.) Marriage line gaskets extend across the entire marriage line to create an air barrier between the sections of the house. It is a significant source of air leakage. Any leak in the marriage line can significantly degrade indoor air quality and create energy loss for heating and cooling systems. 

Usually, double-section modular homes are transported to the site in two separate sections. The marriage joints, wall, and beam joists are aligned and connected at the site. The roof, walls, and floor must be aligned appropriately, sealed, and supported along the marriage line. If you notice damage on the wall or the flooring around your house’s marriage line, it can mean the air barrier has been disrupted. You might also see red water drips, which is a sign that the gaskets are damaged. 

What is a Marriage Wall? 

Simply put, the marriage wall is the wall adjacent to the marriage line. The marriage wall is two walls coming from two different house sections to create a thicker interior wall. The thickness is usually twice the other interior walls, going up to 1′ in some manufacturing brands. It is a structural load-bearing wall that you should not attempt to remove by yourself. It requires thorough construction knowledge and experience to remove it without causing any structural damage.

Inspecting the Marriage Line

Before purchasing a manufactured home, you need to inspect the marriage line thoroughly. Other than apparent areas, you need to take a closer look at other sites as well. For example, the plastic that comes with the manufactured home must be looked at as it can get into the line of the structure, which can lead to many other problems. Additionally, the leftover nails and staples must be removed from the line as they can damage the marriage boundary and ultimately degrade the structural integrity of your home. 

Inspecting the Head Duct Gasket of Marriage Boundary

Inspecting the head duct gasket of the marriage boundary can save you from some severe structural damage in the foreseeable future. The head gasket should be in a smooth condition. Otherwise, it can lead to your manufactured home having some severe problems with its sheer walls. If the shear wall is not strong enough to withstand wind, the house might collapse in extreme weather conditions. 

Additionally, the gaps in a marriage boundary should not exceed more than an inch. If the gap gets wider or uneven throughout the boundary line, it needs to be readjusted with professional help. If the gap is left untreated for too long, it can create roof leaks, weakened structural integrity, and several other very expensive issues.

How Do Seal Marriage Line in a Mobile Home?

• Install a gasket along the entire joint of the marriage line. If the gasket is already installed, proceed to perform the following steps. 

1. Before joining the sections, install the gasket to the walls, ceiling, and floor.
2. Next, fold the gasket in half and secure it along the pairing surface with nails or staples. Secure at intervals of 6 inches in the center (NFPA 2013).

• After putting the sections in place and attaching them, using an appropriate sealant such as caulk, foam, or silicon, air seal the entire perimeter of the gasket to the section walls, floor, and ceiling,
• The next step is to visually check the marriage line to ensure the gasket installed along the line of the module and the outer part of the gasket is completely air sealed. It can be done using a smoke pencil or feeling the airflow with the back of the hand. Blower door testing, which measures air barrier effectiveness at the whole-house level, can also indicate whether marriage joints have been successfully sealed. 

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