The construction of a modular home usually takes up to 7 months from design to completion, though the modular construction itself can be finished in as fast as just 2 months. Modular construction is a highly industrialized building process with several steps being highly mechanized. The industrialization of the modular construction process brings this technique closer to an assembly line than to a traditional construction procedure, turning this building method into one of the fastest.
Still, the mechanized construction of a modular home is only one part of the overall construction of the house. From the moment the design process starts to the instant the house is totally finished and ready to be lived in, there are different phases that need to be completed and these are pretty similar to other construction techniques such as stick-built.
Modular home construction timeline in comparison to stick-built:
| Modular Construction | Stick-built | |
| Design phase | 2 to 4 months | 2 to 4 months |
| Building permits | 3 to 12 months | 3 to 12 months |
| Foundations | 2 to 4 months | 2 to 4 months |
| House building | 2 to 4 months | 2 to 5 months [1] |
| Total time | 7 to 20 months | 9 to 25 months |
Constructing off-site allows the two construction phases of house building and foundations to take place simultaneously. Most of the steps required to build a modular home are just the same steps that any other traditional construction process follows. However, modular construction has a great advantage over traditional methods since the most demanding part of the construction, the house building, takes place off-site in a factory-like environment.
Why is modular construction faster than other traditional on-site building techniques?
Modular construction is considered a Modern Method of Construction (MMC). This is a category assigned to a group of construction techniques that stand out from traditional construction thanks to their highly innovative processes. MMCs have the capability of reducing the construction timeline by prioritizing automation processes [2].
Building a house with modular construction means that a minimum of 70% of the overall process takes place in a manufacturing plant [3]. The overall volume of the modular home is manufactured up to completion in this setup, in the form of modules that once on the building site will only need to be assembled to obtain the finished house.
Given that modular homes are permanent types of construction, it is indispensable to build sturdy foundations and prepare the land, as any other traditional construction method will do. This process will take just as much as it would with other construction methods. However, with modular construction, the land preparation takes place simultaneously to the module construction, cutting down the construction timeline enormously.
The modular home construction timeline
The most attractive quality of the modular home construction process is the prefabrication phase. This is the stage that sets modular methods apart from any other construction techniques: it is faster and carried out off-site allowing the simultaneity of different construction phases. However, some parts of the modular home construction timeline take just as much time as any other traditional construction method would.
Designing the house
Generally, it takes from 2 to 4 months to design a modular home [4]. Before any construction work can start, the modular home needs to be designed. The duration of this phase will fluctuate from one client to another, though with custom-designed modular homes it won’t vary much in comparison to other construction techniques. However, it is common for modular construction to offer predesigned models which are already designed homes that are just ready to be manufactured.
Choosing a predesigned module will save an incredible amount of time in the design phase. Still, even if it highly reduces the design needs, an already designed modular home has to unavoidably go through the design phase to customize some details and define the foundation requirements according to the land where the house will be built.
Obtaining the building permits
The time required to obtain the building permits highly varies from one jurisdiction to another: while some jurisdictions take just 3 months, others require as much as 12 months to release the building clearance [5]. Obtaining the building permits is a requirement that every modular home has to attain to. Despite being prefabricated constructions, modular homes are treated as permanent houses that have to be built according to the local building codes and regulations.
Therefore, even before construction starts, it is required to acquire a building permit from the building department of your jurisdiction. In order to obtain the building permit, you will have to present a set of documents that include the floor plans of the new modular home [6]. Therefore, you won’t be able to start this process until the design phase is completed.
Modular construction: the manufacturing Phase
The manufacturing phase of the modular home takes from 2 to 4 months [4], [5], [7] and in this short period of time, the overall volume of the house is completed. This phase is unique from modular construction and it is the reason behind the time reduction in modular constructions. The house is built per modules and every module is fully finished in the factory-like environment: from frame construction to exterior finishes, including all the final components such as wiring and HVAC.
The manufacturing process takes place in a controlled environment that is highly mechanized and protected against any weather events. These conditions set the perfect environment for a fast-paced construction while reducing any delays due to climate factors or even transportation delays since the centralization of the construction translates into centralized storage where materials are delivered in bulk to be utilized in different projects [8].
On-site construction works and Foundations
This phase of the modular construction process is very similar to that of traditional construction and it takes around 2 to 4 months to be completed [4], [5]. However, modular construction counts with a huge advantage: the construction of the foundations takes place simultaneously with the construction of the house volume. Therefore, even if the foundation works take just as long as they would with traditional construction, the amount of time saved by using the modular method is enormous.
Once the foundations are finished, the pre-manufactured modules are delivered to the building site to be assembled. The assembly process can be done in as fast as 1 single day [9]. Then still some finishing works are required to obtain a fully working house. Since the construction of the modules is done with these needs in mind, the finishing works are usually fast to complete.
References:
- How long does it take to build a timber-frame home? Legacy Timber Frameshttps://www.legacytimberframes.com/hrf_faq/long-take-build-timber-frame-home/
- What is MMC – Modern Methods of Constructions? Dorcehttps://www.dorce.com/what-is-mmc-modern-methods-of-construction/
- Prefabricated vs. modular homes: what’s the difference? Royal Homes https://www.royalhomes.com/tip/prefabricated-vs-modular-homes-whats-the-difference/
- Discover a better way to build your home. Plant Prefab https://www.plantprefab.com/homebuyers/#process
- You have questions, we have answers Blu Homes https://www.bluhomes.com/fact-sheet
- How to obtain a building permit – A guide to the homeowner The Corporation of the township of Georgian Bay Building Department https://www.gbtownship.ca/en/living-here/resources/Documents/Building-Permit-Guide.pdf
- Frequently Asked Questions – Process. Method Homes https://www.methodhomes.net/frequently-asked-questions
- Blaney Flietner, M. Modular Homes go Greener Bob Vila https://www.bobvila.com/articles/454-modular-homes-go-greener/
- Semler, K. How does a modular home get assembled? – Part II: Set day Impresa Modular https://impresamodular.com/how-does-a-modular-home-get-assembled-part-ii/
