I was first interested and tried to engage with a modular company about 8 years ago right before the economy imploded and found the process to be pretty frustrating. Like many, I was originally driven to modular during a value engineering exercise; Modular was mentioned by one of the architects on our team and a quick web search identified a couple of local modular companies for us to contact. We were working with a design completed by Classic Colonial Homes. The building was traditionally inspired with relatively simple massing. It seemed like a sure fit for modular so we set up a call and sure enough a couple days later we were on the phone talking with an informative salesman.
I can't recall the specifics of the discussion, it was pretty long, but the summary was, "We can't really build the house like you set of drawings shows, and if we do it's going to cost more money than just hiring a local GC and finishing it yourself." Needless to say, I was perplexed. Modular was cheap right? How could it not be, it was manufactured with cheaper labor in a controlled environment with more efficient processes. It was Henry Ford, making cars on his assembly line. Why would I ever use modular if it wasn't cheaper than stick-built and how did this company survive if they couldn't execute on a simple project like ours? It was clear that modular was off the table for the project and we would need to find another solution to our budget crisis, but despite my disappointment, I couldn't help feel like I was missing something and I needed to get to the bottom of it.
Step 1: Put on your design handcuffs
The first thing that really struck me about the modular construction restraints were the restrictions on size. The easiest way to understand these restrictions is to realize that the whole industry is built around shipping restrictions: How big of a box can you fit on a truck? It's a bit like playing with legos and the pieces can only get so big. If you go over, you better sit back down at the drawing board and change the design because your project just got really expensive! In fact, there are maximums and minimums. In our case the restrictions were as follows:
Despite the restrictions, you can still design amazing houses with modular like this on we are currently working on
Box Width Maximum: 15'-0"
Box Width Minimum: 11'-0"
Box Length Maximum: 60'-0"
Ceiling Height Max First Floor: 9'-0"
Ceiling Height Max Second Floor: 8'-0"
In reality, this is a relatively flexible set of parameters, meaning you can design many houses using these building blocks, but you need to be aware during the design process or you can quickly find yourself backed into a corner with no way out. More importantly, your client needs to understand these restrictions as in modular construction there is no such thing as "fully custom."
The process of educating yourself, your design team and your client is a critical first step to successfully execute a modular project. Know your building block sizes first. Understanding these blocks and their restrictions needs to be the first step in the design process to avoid costly and difficult design alterations during later design phases of a project.