Joseph from Boulder Co asks:

My question is about the viability of shipping containers as building material. I have seen amazing things being done with them and I’m wondering if it would work for our current project.

We have the intention of creating a glamping vacation rental getaway (620 – 1240/sf) for parties of 4-8 people gearing towards millennials and tiny home fans. (Attached is a typical 2/1 draft design)

Concerns we have are:

– refinancing after project is up and running to get initial investment money back to investors.

– construction cost with containers vs standard building materials. Our partner builder has done builds in CA for $110-130/SF hard cost.

– city/county planner objections to use of material

I appreciate any thoughts you have. Thank you again for all your work and content.

Joseph this is a great question:

In my experience shipping containers make for a robust structure. I love the idea from the perspective of re-using materials that might otherwise go to the scrap heap for recycling. But here’s the problem with shipping containers. They’re 8 feet wide. When your building block for your room is too small to fit basic furniture, the resulting finished product has extremely awkward room sizes. For example, if you’re making a bedroom, you need a minimum of 11.5 feet to fit a bed, a walking space and a dresser in that dimension. If you want a queen sized bed with two bedside tables, you need a minimum of 9 feet just for the furniture to fit in the room.  If you want a bit of breathing room it needs to be larger. In both cases, the minimum room dimension is above 8 feet. So you’re going to be cutting out a wall, a thick steel wall. That’s an expensive cut. Now your room is 16 feet wide. That’s a nice dimension, but it can lead to a larger footprint than you’re after.

Wood framed construction is not that expensive. I’m building apartments and single family homes all day long for about $120-130 per SF. So there is no savings in the overall cost of construction by using shipping containers compared with conventional stick built. Let’s look at a standard 8 x 20 foot container. They can be purchased for $2,500 each plus delivery. I just took delivery of one of these and paid $300 delivery. If you look at the cost per square foot for a structural box, you’re looking at $17.50 per SF.

Most of the cost of construction is embedded in the infrastructure and the finishes. The total cost of framing is about 15% of the total project cost in a regular stick built home. But even when you’re building with containers, you need some framing for the interior walls. This might be wooden strapping which is less expensive than structural framing. But it’s not zero. When you’re building with shipping containers, the insulation becomes key. Metal containers are highly conductive. You need channels to route the utilities like water, sewer, electricity, and HVAC. In order to get sufficient insulation, you end up with thick walls, or expensive insulation. If you have thick walls, now your interior room dimensions shrink and you end up with a smaller room below the 8 foot dimension.

Framing makes up a small percentage of the overall construction schedule. Most of the time is consumed during the rough-in and interior finishing stage. Even if you set the framing portion of the schedule to zero, you would not save more than about 20% of the overall schedule, with virtually no savings in investment.

I want to thank you Joseph for a great question. It’s one of those ideas that intuitively looks like it should be a benefit, that doesn’t get realized in real world practice.