A site-built house is constructed entirely at the building site. They conform to all state, local or regional codes where the house is located and are often called 'stick-built' houses. Site-built homes run all sizes and shapes and generally take anywhere from 2-3 months to well over a year to build, depending upon size and finish quality. A well-built, cared for site-built home generally increases in value over time, although its location plays a key role in value. Realtors are generally involved in the sale and re-sale of these homes.
Modular homes are built in sections at a factory. Modular homes are built to conform to all state, local or regional building codes at their destinations. Sections of the modular home are transported to the building site on truck beds, and then joined together by local contractors. The home may be placed upon a pre-poured basement or on a crawl space. Local building inspectors check to make sure a modular home's structure meets requirements and that all finish work is done properly. Modular homes are sometimes less expensive per square foot than site built houses. A well-built modular home should have the same longevity as its site-built counterpart, increasing in value over time.
In some countries, especially in Japan, this build technique is the preferred method. A licensed Realtor may sell a modular home. Most banks, appraisers, and insurance companies treat modular homes the same way they do site built homes--a house that's constructed entirely on your property. Ask the mortgage brokers and banks in your area to explain how they finance modular homes.
Manufactured homes were formerly referred to as mobile homes or trailers, but with many more style options than in the past. Manufactured houses are built in a factory. Manufactured homes conform to a Federal building code, called the HUD code, rather than to building codes at their destinations. One of the standards that is often referenced by local building codes to restrict where manufactured homes may be placed is the roof pitch. Manufactured homes generally have less pitched roofs than either modular or stick-built homes.
Manufactured homes are built on a non-removable steel chassis. Sections of the new "double-wide" or even newer “triple-wide” manufactured homes are transported to the building site on their own wheels and are joined at their destination. Segments are not always placed on a permanent foundation, making them more difficult to re-finance.
Manufactured home owners often take off the wheels and place the home on concrete blocks with "skirts" around the perimeter. Building inspectors check the work done locally (electric hook up, etc.) but are not required to approve the structure.
Manufactured housing is generally less expensive than site built and modular homes. Manufactured homes sometimes decrease in value over time. Realtors are not allowed to sell manufactured homes. They are sold by licensed manufactured homes sales reps and most often financed with special manufactured homes loans. Keep in mind that in order to live in a manufactured home you will have to place it in a manufactured homes park. These days, most communities will not allow you to place a manufactured home out on your own lot. Check with your Township building inspector for the rules on that.
What Do the Differences Mean to You?
Communities generally have no restrictions against traditional, site built homes, but they will have local building codes that must be followed. Many housing developments do set minimum size requirements and stipulate you must build a house that conforms to published restrictive covenants or be approved by an architectural review committee. Most communities and developments allow modular homes. Some do not, but in many of those cases the restrictions seem to have been imposed because of an ongoing confusion about the differences between modular homes and manufactured homes. Local building ordinances or the restrictive covenants and deed restrictions in a development often exclude manufactured homes. You should investigate the deed restrictions and local ordinances thoroughly before purchasing land for any type of new home.
More on Modular homes.
Modular homes are built in sections in a factory setting, indoors, where they are never subjected to adverse weather conditions. The sections move through the factory, with the company's quality control department checking them after every step. Finished modules are covered for protection, and then transported to your home site. They are placed on a pre-made foundation (either a basement or a crawl-space), joined, and completed by your local builder. How long it will take the manufacturer to build your order depends on your design and the manufacturer, but some modular homes can be built in the factory in as little as 1-2 weeks. And since modulars are built indoors, there's never a weather delay. It usually takes another 2-4 weeks for your local builder to complete the home once it's delivered to the building site.
Contrary to popular beliefs, not all modular homes look alike. In fact, unless you were there to see the house delivered and assembled, you might not guess it's a modular home. Modular home manufacturers use computer aided design programs to draw plans to your specifications, or to modify one of their standard plans to suit your needs, so nearly any home plan can be turned into a modular home. It's true that some modulars are very basic and resemble double-wide manufactured homes, but the two structures are still built in different ways. Each manufacturer is different, so be sure to ask questions about flexibility if you would like to design your own home. Today's modular homes come in both one and two story models, with Cape Cod styles being very popular.
All types of homes have their places in the housing spectrum of any community. Manufactured homes have the appeal of relatively low cost, just as renting a house or apartment might appeal. Modular homes generally have lower construction costs than a stick-built home and may have other advantages in the areas of utilities (lower heating and cooling bills due to better insulation and better control of the build). Site-built homes offer the maximum in flexibility and the opportunity for increased craftsmanship (and well and the risk of a sloppy build).
Realtors are supposed to accurately identify a home as being a modular when they list it and that information should be on the MLS sheet, but some don’t always do that. If you believe that the home that you are looking at is a modular, but it is not identified that way, look in the basement (assuming that there is one) All modular homes have a fairly easy to identify “marriage line” running the full length of the sections that were transported to the site. Usually there will be support posts of a beam under this line, which always has two full length wooden beams or joists (usually 2 X 10’s) – one for each half of the house. That beam acts just like the sole plate around the rest of the outside perimeter of the each section of the house. Those sole plates will normally be bolted together at the marriage line.
Some home re-modelers are now using modular add-ons as a quick and less expensive way to add living space to homes. You can literally order a “room”, complete with it’s own roof, windows, electrical wiring in place and ready to set on the foundation that you add to the existing house. You could probably add a complete second story to an existing ranch house that way, assuming that the first story walls can bear the load. I've got one set of clients who like to think about what they would do to improve the houses that we've looked at and they constantly talk in terms of adding a box here or there, where the box is actually a modular room. They have done this in the past and understand both what's involved and what the costs are to remodel using that technique.
Hopefully this post helps you to better understand the differences between the site-built and modular homes that you might see. We may well see more modular homes in the future, both as a way to hold down construction costs and to better control the quality of the build. Modular home manufacturers have removed most of the restrictions on what can be factory built - single or multi-story. There is little but residual misunderstanding to keep you from choosing a modular home these days and now you can't claim that any more.