Modular home costs were one of the first questions we confronted after identifying modular construction as a logical option for our home. The next issue was whether it would truly be more cost-effective than hiring a contractor to build on-site. This guide explains what modular base prices usually include – and the on-site costs that often catch homeowners off guard.

We began researching our options as early as 2016, when far fewer modular builders were operating. Websites showcased beautiful modular homes you could choose from while highlighting speed, efficiency, and quality. But the one critical question was: what does a modular home really cost?

Modular Home Costs: What’s Really Included?

After reviewing builder websites and speaking with a few companies, modular home costs seemed better than expected – especially given what was included. Most base prices cover standard windows, doors, and fully finished kitchens and bathrooms, reinforcing our idea that modular homes arrive nearly move-in ready.

What we learned – and what is important to understand – is that off-site construction refers only to the portion of a modular home completed in the factory. We initially used the square-foot prices to compare against contractor pricing in our area. It wasn’t until we requested a detailed quote that it became clear the advertised square-foot price did not reflect the full cost of a completed modular home on site.

On-Site Work: More Than Just Site Prep

From our background, we thought we knew the difference between off-site and on-site work. Logically, we assumed on-site work meant permits and site preparation including a foundation.

There is more to it.

Once modules are ready to be transported, the off-site portion is considered complete from the factory’s perspective.  What follows are the expenses we found that can exist beyond the factory base price. 

Delivery and Set-Day Costs

Factory schedules continue regardless of what’s happening on your lot. Typically, the factory and on-site contractor coordinate a timeline so the modules are delivered shortly after the foundation is ready. However, if site preparation is delayed or the weather is not cooperating, the factory often cannot pause or slow construction. Modular homes are built using an assembly-line process, which allows for precision and efficiency but makes it logistically, and economically, unfeasible to stop a build midstream.  If the modules are ready for delivery but the site is not, storage fees may apply – this should be addressed up front.

When the modules leave the factory, they are transported to the site by truck. Each module typically requires its own truck, with per-mile delivery charges. Because modules are classified as wide loads, escort or spotter vehicles are often required as well.

Once the modules arrive, another major on-site cost comes into play: the crane and setting crew. The crane is used to lift and set the modules onto the foundation.

The module transportation costs plus the crane and setting crew costs are not included in the square-foot price.  This is common because the distance from the factory to the site differs from customer-to-customer.  If the factory is coordinating this portion, it will be listed as an upcharge.  If it is missing from the quote, it will go into the on-site expense column on your budget.

Post-Set Work: Not Part of the Modular Cost

Once the modules are set, it’s easy to think the modular costs are behind you. This is a common misconception and one that’s often glossed over.

After set day, the following work still remains:

• Tying the modules together
• Testing and certifying fire sprinkler systems
• Tiling or grouting that would not survive transportation stress
• Installing items shipped loose (such as stairways, both indoor and outdoor appliances)

All of this work can be estimated, but if you’re not aware of it ahead of time, it’s easy to underestimate both scope and cost, which can quickly blow a budget.

Questions You Should Be Asking Early

As you research modular home costs, it’s helpful to keep a running list of items that may involve upcharges or require additional on-site work. Just as important is understanding what each builder considers a standard feature versus an upgrade, since these differences can significantly affect the total cost and make direct comparisons difficult.  In a future post, we’ll share which upgrades we chose to defer, which standard options we will replace later, and which improvements we will handle ourselves.

Here’s a starting list of questions that are easy to miss when you are early in the decision-making process:

• Do you charge storage fees if the site isn’t ready?
• Are stairways installed or shipped loose or are they built on-site?
• Are outdoor appliances, such as HVAC condensers, installed at the factory or on-site?
• How much do you estimate module delivery and crane day will cost?
• Do you install the solar panels and energy storage system (Important in California)
• Is sales tax included in the price?  If not, what is the taxable percentage used?
• Do we hire our own contractors to complete post-set work?

That last question is especially important. We share, in a separate post, our experience working with dealers and directly with a builder – each approach has its own advantages and trade-offs.

Final Note

Whether you choose a modular home or a traditional on-site build, certain costs remain unavoidable. In future posts, we will share our “adventures” with:

• Obtaining planning approvals
• Permits (and then more permits)
• Added costs for small or constrained lots
• Public utilities and road work
• Finding contractors
• Navigating state, county, and city codes in California