In Building Foundations for a Rocky Landscape, we completed the footings and now we will share how we completed the foundation work and our reasons why we poured concrete for the octagon in the centre of the Sea Container Cabin.
Replacing standard foundation building methods with piers
If you want to minimize foundations work with shipping containers, you can skip the standard foundations used in traditional building methods and use piers instead resting the corners of your shipping containers instead of having to support the perimeter of your structure. With a clean set of footings to build on, the forming of the outer box piers and the centre octagon takes place. The centre octagon has structural box piers located at each of the octagon points that hold one end of the containers. There are 20 outer box piers that hold the outer ends of the containers and supports the outer posts and beams for the roofing system.
Choice of floor construction for the great room
In the Concept & Design section, we describe the features of our centre octagon great room. This great room could be designed with a suspended wood floor system, or with an elevated concrete slab on foundations. We selected a concrete centre hub for the following reasons:
- Permanent long term durability
- Invincible to damage from beneath from insects and animals (carpenter ants and porcupines love to eat wood!)
- Ability to heat a thermal mass with in floor radiant heat piping in an insulated concrete slab
- Superior weight load capabilities for heavy wood stoves
- Waterproof for winter gear drying in front of a fire, and in the event of a leak from the interior water tower there’s a floor drain in the centre
Images Capturing Step by Step Foundations Work
Centre octagon forms with structural box piers and concrete curtain walls
Structural box piers with embedded steel welding plates
Centre octagon after concrete forms removed
Rebar floor ties inset into octagon foundations (Picture 1)
Rebar floor ties inset into octagon foundations (Picture 2)
Outer box pier concrete forms
Centre octagon backfilled, compacted, and insulation laid
In floor heat piping installed before concrete floor is poured
Completed foundations, great room octagon floor, backfilled, and graded
Panorama of Sea Container Cabin site – click to enlarge
Optimize the benefits of building with shipping containers for more than foundations work
We have figured out how to optimally build homes out of shipping containers in cold environments while meeting Ontario’s building code. And after we figured it out, we wrote about it. Contact us for your DIY shipping container kit so you can experience what’s behind building your own permanent shipping container home.
Hi,
My name is Watson and I was wondering. Can you use shipping containers as a foundation for building with other shipping containers?
Hi Watson. The short answer is Yes. You always need a foundation design for the first container level, but if you want to stack another container on top, then we need ensure the base foundation design is capable of holding the extra weight and stresses. Containers are designed to stack on their corner points, and shipping containers are stacked as high as 20 high on the large shipping vessels when carrying deliveries around the world. However many fancy home designs tend to want to position containers on top of each other without aligning the corner points. This creates the need to use additional structural members, beams, posts, etc. to accomodate those design features. Hope this helps. Jason.
Hi. Can we use steel post as foundation to a 40ft. container for the purpose of elevating it 9ft above the ground? We plan to leave the lower level open and use as garage.
Thank you and I will appreciate your advice…
Yes that is possible. It needs to be structurally engineered and specified of course. If you are in Ontario we would be happy to assist you with your project. Cheers, Jason.
We are wanting to use shipping containers for a fire department training burn building. We are wanting to have these on concrete footing posts. On a 40 ft container what is the suggested span between these posts? Also we will only be stacking these 2 containers high so how deep should these be? We are in Georgia.
Hi David, good question. In Canada, our building codes typically require concrete footings and posts that go at least 4 feet deep in order to get below the frost line. So I would assume that is a good planning assumption for you. However your local building official / permitting office will specify your local requirements. As for the span between posts, if your 40 container is not compromised with holes cut in the sides then you only need to have 4 posts, one at each corner of the container. Containers are designed to structurally take all loading at the corners.
Cheers
Jason