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What is A Marriage Line in A Mobile Home and How to Seal It

Mobile home marriage line

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?

Marriage Line in A Mobile Home
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. 

Do you have any additional questions about mobile homes? Comment below and let us know!

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9 Responses

  1. If wood beams are used in the floor as the edge support along the marriage line, in addition to sealing the line with a gasket, isn’t it important to tie the two beams together structurally with bolts or some other means? One would think this is commonly done.

  2. Who sells marriage line indoor seals,or trim to cover the marriage line?in a open kitchen to den area,and a hallway,I had to remove the trim board,14ft,and 4′ I sealed the line with foam,now I can’t find anyone who sells the product to /trim,to cover it!?? Anyone know who sells them? A fauz wood box is 500+$,a 1×6 box I’d construct is 100$, I just want the flat vinyl with insulation cover that I removed!!

    1. I appreciate your comment and your inquiry about where to find marriage line indoor seals or trim. Unfortunately, we don’t have any specific recommendations for a supplier who offers these products. It sounds like you’ve explored various options and have a good idea of what you’re looking for.

      Sometimes, finding specific parts or materials for mobile homes can be a bit challenging, but you might want to consider checking with local mobile home supply stores, online marketplaces, or even contacting the manufacturer of your mobile home if you have that information. They might be able to point you in the right direction.

      Thank you for reaching out to us, and I hope you’re able to find the solution you’re looking for. Best of luck with your home improvement project!

  3. Great article on the marriage line in mobile homes! It’s important to know how to seal it properly for better energy efficiency and comfort inside your home. Thanks for sharing this informative post!

  4. Great article on the marriage line in mobile homes! It’s important to know how to seal it properly for better energy efficiency and comfort inside your home. Thanks for sharing this informative post!

  5. Thanks for explaining the concept of a marriage line in mobile homes! As a long-time mobile home owner, I had no idea that this was even a thing. It’s great to know how to properly seal it to prevent water damage and structural issues. Definitely saving this post for future reference!

  6. Great article! I had no idea that a marriage line in a mobile home could be a potential issue. I appreciate the tips on how to seal it and keep the home safe and secure. As a mobile home owner, this information is invaluable to me. Thanks for sharing! – John

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