In order to save on construction time and as a result, save on total project costs, individuals looking to build a duplex might want to consider building a prefab or modular duplex. With options for both standard and pre-designed homes available, there are many builders who can meet a wide variety of client needs. Below, we have outlined some of the best options for prefab and modular duplexes as well as addressed common questions about the process. If you would like assistance building your own prefab duplex, speak with a member of our prefab concierge team.

Understanding Prefab and Modular Duplexes

What is a prefab duplex? What is a modular duplex? And what’s the difference between the two?

A duplex is characterized by two residential units which are often placed side-by-side or one on top of another. Technically speaking, a prefab duplex refers to any duplex that is built using prefabricated construction techniques. This includes modular construction, kit home building, panelized home construction, and manufactured construction.

Modular duplexes are a subset of prefab construction where box-like module(s) are built off-site, shipped, then set, and finished at the final build site. So, there is very little difference between the two as both will have the design elements of a duplex.

How much does a prefab duplex cost?

The duplexes included in our list have turn-key costs starting at $600,000+. These estimates are based on the all-in costs to build each home, not including land. It is worth noting that there are both more affordable and higher-end, fully-custom prefab duplexes beyond those that are included on our list, depending on your budget and preferences.

To determine what it will cost for your own prefab duplex, there are a number of factors to consider:

Land
Permitting fees
Site preparation - site assessment, excavation, utilities, foundation
Home cost - modules, panels, kit components from the builder
Delivery - many prefab companies serve large areas of the U.S., if not the whole country. It is worth inquiring if they have regional manufacturing facilities or if they ship materials from their headquarters, in which case, long-distance shipping costs can add-up
Installation/set - setting modules on a foundation & tying them together, or the assembly of the materials kit or panels
Finishes - depending on the company and your project’s needs, some modular homes can be delivered in a highly-finished state (around 90% complete). This means homes can arrive on-site complete with flooring, cabinetry, electrical, and plumbing; this requires little on-site work for the home to be move-in ready. Kit homes and panelized homes require significantly more on-site work to assemble and finish, increasing the local cost section of your budget

How long does it take to build a prefab or modular duplex?

Like other styles of prefab and modular homes, a prefab duplex can often be built quicker than a site-built home. While the exact timeline of your project will be determined by the length of the design/engineering process, permitting approvals, off-site build times, and on-site assembly & finishing, it is our experience that a prefab duplex can be move-in ready anywhere between 9-16 months.

Prefab and Modular Duplexes For Sale

McKinley by ZipKit Homes

The McKinley by ZipKit Homes is a 1,024 square foot cottage that is built using a panelized kit home. With 2 bedrooms and 2.5 bathrooms, the McKinley has options to be used either as a single-family residence, duplex, or multi-family project. ZipKit Homes’ design has interesting features such as a modern exterior, patio, and open floor plan.

ZipKit Homes is based in Pocatello, Idaho, and can work with buyers throughout the Western United States. Although regional cost differences will affect the cost of building a McKinley, we estimate that buyers in mid to high-cost areas can expect to pay $375,000 per residence (i.e. $750,000+ for a duplex).

Duo by Module

The Duo by Module is a 1,728 square foot cottage that is built using modular construction. With 3 bedrooms and 2.5 bathrooms, the Duo is a top-bottom duplex that features a footprint that is well-suited for urban infill lots. Module’s home has interesting features such as a modern exterior, a smaller one-bedroom unit on the ground floor, and a larger, two-story apartment on the second two floors.

Module is based in Pittsburgh, Pennsylvania and can work with buyers throughout the Mid-Atlantic U.S. (PA, NY, NJ, MD, DE, OH, WV, VA). Although regional cost differences will affect the cost of building a Duo, we estimate that buyers in mid to high-cost areas can expect to pay around $600,000.

Custom Duplex by Clever Homes

The Custom Duplex by Clever Homes is a fully-custom cottage that is built using a combination of prefab building techniques. Because it is a fully custom design, Clever Homes can work with buyers to design a unique duplex.

Clever Homes is based in San Francisco, California, and can work with buyers throughout the entire U.S. Because Clever Homes works on fully-custom projects, it is difficult to estimate a project cost however, typical custom homes from Clever Homes can range from $500 - $600 per square foot to build the Custom Duplex duplex by Clever Homes, not including land.

Key Takeaways of Building a Prefab or Modular Duplex

Just like site-built duplexes, prefab and modular duplexes are characterized by two residential units which are often placed side-by-side or one on top of another
As with most types of residential construction, the turn-key cost of your duplex will be heavily influenced by several factors: location & local labor cost, standard vs. custom, site work costs, and degree of finishes. That being said, buyers with mid to high-end costs can expect turn-key pricing from $400 - $600 per square foot
Similar to cost, the timeframe to build your duplex will be largely determined by factors like permitting time, standard vs. custom, and whether or not your selected company has a backlog of orders. While some modular homes can be built in as little as a few weeks, the entire process: from the time you put your deposit down until your duplex is move-in ready is often between 9 - 16 months
There are a number of builders that sell prefab and modular duplex homes including ZipKit Homes, Module, and lever Homes