Designing your home with shipping containers involves a lot of questions. How many do you want? What size?

How will they be connected together? How do you want to finish the openings? Whilst these are all valid questions, when engineering your home, there are a number of important questions to ask about the site, soil and regulations. By engineering your home based around good, accurate site information you will get a better design, accurate cost estimating and smooth permits.

Planning Considerations

Not all sites are suitable for building a container home. Understanding any site specific issues will help eliminate any costly surprises.

Accessibility – Can the containers be easily delivered to the site? As most standard sized containers (20’, 40’ or 45’ ISO) will arrive by truck, you need to ensure there will be good road access, turning circle and headroom. If the site doesn’t have great road access, tight turning circle or not much headroom then you may have to use a crane to lift the containers down from a nearby road. This will incur additional costs.

Topography – A flat site will make it easier to lay out your foundations, and keep them all the same level. If your site is very hilly you might have to have some extensive cutting and filling to ensure your building pad is flat. Alternatively you might have to design your foundations to accommodate the hill; which could involve having piers to different levels or a stepped foundation. This will increase your costs compared to a flat site and will require some site specific engineering.

Utility Access – How easy is it to connect to water, sewer, electricity and communication services? Depending on the distance to the existing services and the terrain your costs can vary massively. If your site is remote and there are no existing services then you may have to include onsite water, septic tanks and off grid power. Each of these will have their own engineering considerations.

Geotechnical Investigation

The foundations of your container home will support the containers, contents and occupants. The performance of the foundation depends on the soil’s ability to support the loads.

By carrying out a geotechnical investigation we can determine the relationship between the soil and the loads. Boreholes will be drilled at representative locations around your building, samples will be taken at set depths and tested in the laboratory to determine their bearing capacity, compressive characteristics and other information your foundation engineer will require. From this information we will determine what soil bearing pressure the ground can support, how much settlement will occur under this pressure and if there are any special conditions.

If you don’t carry out a geotechnical investigation you’ll be designing your foundations around assumed ground conditions. If they turn out to match what you assumed then everything will be fine. However if they don’t match (which is quite common), you will have a poor performing foundation. This can range from unsightly cracking to more serious issues where the whole structure has to be lifted and the foundations completely redesigned.

CeedCivil will work with you to plan the geotechnical investigation as part of your shipping container home engineering.

Foundations

Your foundations need to support the point loads from the corners of your container.

The most common way to achieve this is using isolated piers or pads of concrete. These will be placed either on or close to the corner castings of your container. The size of the piers will depend on the bearing capacity of the ground and the amount of area needed to spread the point loads into the ground. Rebars will be added to the piers to give continuity and resist the lateral loads from wind and seismic. The connection between the corner castings and the piers must be detailed to stop any lateral movement.

By using grade beams between the piers you will have a more rigid foundation to help spread the loads and reduce any differential settlement. This will be useful if you have large spans or more erratic soil conditions.

Some container homes will use continuous strip foundations. This is useful if you have lots of wall area which will benefit from being spread out. You will need to analyse how the point loads at the corners will transfer into the strip and detail the connection to avoid stress concentration.

Regulations

There is a wide variety of regulations around shipping container home engineering depending on where you are. Some building departments will have had experience of looking at container homes and will know what to expect. Others will not have had any experience and will have lots of uncertainty when looking at your permit application.

Understanding the regulations around your site will help you avoid any issues. If the building department requires specific window sizes for egress from sleeping rooms, specific fire separations between your garage and living area, or specific requirements for accessory buildings then this will impact on your design. It is much cheaper to incorporate these into your design than change them once you have completed the design.

As part of our initial services CeedCivil will research the regulations around your project to ensure we know what applies to your project. We will also ensure your application is structured to incorporate these requirements. https://ceedcivil.com/