A modular home being fabricated in a factory

A modular home, also known as a prefabricated or prefab home, is a great option for homeowners who don’t have enough time to supervise engineers, architects, or construction sites.

Modular homes are built in factories and transported to be assembled on the property. Now, you may be wondering, “how long does the construction take?”

This article will highlight ten phases that determine the number of weeks a modular home takes to complete. 

But first, a quick answer to how long the entire modular home construction process takes:

What Is the Typical Modular Home Build Timeframe?

The typical modular home build time is 27 weeks. However, various factors come into play when addressing the period for finishing a modular home. For example, designs, inspection approvals, construction, and fittings must be factored in to determine the completion date. 

The entire construction process breaks down into phases of various lengths. Let’s look at them in more detail.

Home Design (Architectural) Phase (4–12 Weeks)

The first phase of building your modular home is the design process.

This stage may take from four to 12 weeks, depending on the size of the house. At this stage, all home details are picked out, from flooring and cabinets to the roof.

Here all designs are left to your taste, and only expert advice is offered, from the house design to the appliances. Companies only provide consultation and customization of your ideas.

For many, this part is usually the most fun. It’s the phase where you get to creatively choose the physical aspects of your modular home. 

A site visit is scheduled to help the designers know the property topology and amenities availability. They will also inquire about the access route to the proposed site. 

homeowners standing around a table with blueprints on top discuss their modular home's design

Additionally, they will determine the site preparation time, assess approval requirements, and build a budget. Once you agree on the design and the amount for completing the house, a 5% deposit will start your new home.

Financing Phase (1–7 Weeks) 

One of the shortest phases in the modular house building process is financing.

Most modular companies offer to finance the construction. However, if your preferred prefab firm doesn’t provide funding, a homeowner mortgage will suffice. 

There are limitless options available for funding your homeownership. We recommend choosing construction loans with a low-interest rate of 5-8%. 

The finance phase will take one to seven weeks, depending on the lender approval process. For example, a standard mortgage approval will only take a week, while a construction loan takes eight to nine weeks. A modular firm’s financing takes five to seven days to approve.

Permit Plans and Approvals Phase (4–25 Weeks)

This phase covers three main stages: 

  • Site plan approval 
  • Zoning compliance 
  • Construction permits

After receiving the project drawing from your modular company architecture, you can present it to the local jurisdiction for review. The process might take several weeks before final thoughts for individuals. However, a company will only need a week or two for its approvals to pass.

Zoning approval is another phase where the city reviews your project to ascertain it meets the required zoning regulations. If the project fails to meet the required standards, you may request a plan revision.

Lastly, building permit approvals can be accessed through the city website and may take 2-4 weeks.

Building Preparation Phase (2–4 Weeks)

Before a company can start working on your modular home, all building variants must be aligned.

The city inspector will inspect the plumbing and electrical connection to meet the set standards. Company experts will check any missed or overlooked details and correct them beforehand.

The design must be water-tight before the walls and decks are hammered away. This stage is the factory review phase, and it’s included in the construction segment.

Here measurements are checked and counter-checked to avoid any errors. The company does this to prevent material wastage and client conflict.

Factory Construction Phase (9–15 Weeks)

This phase duration is a byproduct of the size of the house. 

However, other variants may derail the construction time like raw material availability, the number of orders, and time of year. However, depending on your home’s size, the number of weeks might be less.

Interior of a modular home factory

This phase is where the builder constructs the home exterior and interior framework. The house is 85% complete when it leaves the factory, and the only work left will be on-site, which involves mud work, electrical, and plumbing finishes.

Site Preparations Phase (1–6 Weeks)

Site preparation duration is dependent on various factors. The most limiting factor is the access road. Building an access road might take time if your building site is in the middle of the forest.

A contractor’s longest time needed for a modular home is two weeks for laying foundational bricks. This stage usually happens on uneven, hilly surfaces. Other factors will also determine this phase length, such as: 

  • Access road construction 
  • Well construction 
  • Septic system 
  • Leach field

Laying Foundation Phase (1–2 Weeks)

The timeline of laying the foundation depends on the house size and material used.

For example, if the house has a raised basement, pouring concrete may need more time. 

Furthermore, rebar or steel reinforcement is required before pouring concrete since the floor is raised. Installing the rebar may take time before the concrete is poured.

A traditionally-poured concrete foundation at a construction site

However, pouring concrete may take a few days if the foundation is not raised. Hardened concrete is also advised depending on the type of backfill topsoil on-site. Other factors that impact laying the foundation include plumbing, inspections, basement waterproofing and backfilling.

Installing the Framework Phase (6–12 Weeks)

In this phase, the modular home is brought to the site. The installation process usually takes six to twelve weeks.

After the foundation is poured and cured, the house framework now begins. Finally, interior and exterior walls are installed in modules.

The top story floor is also prefabricated and will be brought to the site together with other house walls. After ten weeks, the framework is complete, and the mud work commences. The remaining weeks will see the house almost complete.  

Appliances and Hookups Phase (2–4 Days)

This stage is among the final touches where the electrical and plumbing work are completed.

Electrical appliances are connected and tested in all rooms. The plumbing is also complete and tested at this phase. The taps and tubs connected are checked and tested. At this stage, the septic or sewer should function well.

At this point, the plumber should test the house’s air-tightness to meet the city standards. All the city inspection requirements are to be addressed during this phase, and the home’s final inspection is usually scheduled.  

Site Finishing Phase (4–6 Weeks)

Most of the final touches are done at this stage. Mainly, the finishing touches include installing fire escapes and lawns.

Most of the outside vanities are installed, like decks and swimming pools. Paint touch-up is also addressed during this phase, and significant exterior safety gadgets are installed.

The experts usually review the house design to ensure they have covered all agreed terms. The appliances must be tested before the handover. Once the company is satisfied with the work, the final occupancy inspection is scheduled. After the review has been passed, the house is handed over to the owner.


Some of the phases highlighted above may fall within each other, but the number of weeks that a modular home should take to complete is between 20-27 weeks.

However, the exact number is dependent on various factors like site development and weather. Snow or rain may also limit access to the site.

Other construction orders that the company has may also slow down the building time, or city inspections may derail the process. However, with proper planning and finances, most companies boast less than 22 weeks of construction. 


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