Modular vs. Manufactured vs. Stick-Built Homes

Occasionally during home inspections, I run across modular homes. When I find them, I explain to my client what they are and how they differ from stick-built homes.

The 1st photos shows a manufactured home being constructed in a factory. The 2nd photo shows a piece of a modular home being lifted into place at the home site.

Modular homes are built in pieces in a factory which keeps conditions such as rain, wind, or snow at bay. Stick-built homes are built onsite with lumber and other components pieced together. A modular home can be completed in the factory in a week or two whereas a stick-built home often takes 3~4 months.

The large pieces of a modular home are trucked to the site where a permanent foundation (normally consisting of either concrete block or poured concrete) has been completed and is awaiting the home’s pieces to arrive. Using a crane, the large pieces of the home are picked off the truck and loaded and fastened into place. A modular home can be in as few pieces as 2 (a small ranch) and sometimes as many pieces as 8 or 10. Things like dormers are separate pieces which get loaded and secured to the roof. Decks, patios, the air conditioning compressor unit, etc. are then installed.

The easy way for an inspector to determine the type of home being inspecting is to look in the attic. Since the modular home was put together in pieces, the meeting location of the roof framing (trusses) will be in halves running down the center of the attic. The larger pieces are often called ‘boxes’ since they resemble partially empty boxes once they leave the factory. Normally, there will be vertical framing from the right and left (or front and rear) roof trusses with a small space between them. The framing is secured together, but the truss halves are the tell-tale sign. In conventional stick-built homes using trusses for the roof framing, the roof trusses are generally going to be a single truss running the full depth of the attic (roof structure) with no break in the center. The ‘break’ in the center in the modular home roof’s framing is the indicator. Similar seams are often also visible in the basement due to the halves coming together like mentioned above in the attic.

The home’s ‘boxes’ are joined together with hardware, drywall joints are completed, flooring is finished to create a ‘seamless’ look, and there is often no easy indication that the home was built in pieces without knowing the proper places to look. As mentioned above, modular homes are built in factories under ideal conditions. There’s no rain, wind, or snow to get into the home while it’s being completed, inspections are completed within the factory, and each of these can help lead to a very high quality home.

Manufactured homes (called ‘mobile homes’ pre-1976) are very similar to modular homes in many ways. Again, they are also built inside factories where quality control can be better than stick-built onsite plus no weather to impact the construction. Manufactured homes are constructed on a permanent chassis (an underside metal frame like a car or truck). Manufactured homes are most often 1-piece (single-wide) or 2-piece (double-wide), trucked to the location, and then placed onto a foundation. Most manufactured homes are placed on top of strategically placed series of piers (most often concrete block piers) with tie downs cemented into the ground, their wheels and axels are detached but most often left under the home. Sometimes manufactured homes are placed onto permanent perimeter concrete foundations like a stick-built home and I’ve inspected some with full basements. Unlike nearly all modular homes, manufactured homes don’t have attics. Also, manufactured homes are built to HUD codes (called the Manufactured Home Construction and Safety Standards), not the IRC (International Residential Code) that stick-built and modular homes are built to. HUD codes and the IRC do vary in some respects. Currently, PA is on the 2015 IRC (updated every 3 years but not necessarily adopted by PA every time a new version is rolled out). Also, manufactured homes will have a HUD tag (a small metal plate with a unique serial number) on each section normally at one of the exterior corners. A double-wide, for example, will have 2 tags installed normally with sequential serial numbers.

Stick-built homes are, by far, the most common of the 3 types of homes. They are fully constructed onsite using most of the same components as manufactured and modular homes. Their initial building stages are exposed to wind and rain until the roof, doors, windows, and side walls are constructed.

Matthew Steger is a Certified Level 1 Infrared Thermographer, an ASHI Certified Inspector (ACI), and an electrical engineer. He can be reached at matthew@thehomeinspectorsnotebook.com. No article, or portion thereof, may be reproduced or copied without prior written consent of Matthew Steger.