The reason to insulate shipping container home
Shipping container home is a new emerging industry for those looking for something new, sleek, modern, affordable structure but strong and quick deployed. However, as shipping container home is quite new, few concerns remain to be responded in order to gain people’s trust in its reliability. One of the main concerns is the insulation.
The shipping container is actually built for cargo shipping, it is weather-tight and keeps its contain safe and secure. It is initially designed to carry products, not to house humans! As such, insulation appears to be an essential issue to turn this steel structure into a comfortable living or working area. The interior climate of your container can be drastically improved by adding insulation thus reduce your energy bills in keeping the home conditioned.
Furthermore, without insulation, you would not get any approval from your local county to set up your shipping container home as it needs to be built as per code just like conventional homes. Every shipping container home must be inspected by a certified inspector and labeled as a sign of approved. In addition, insulation helps to make your container home sound proof while wall coverings are added.
Thermal Resistance Defined
Thermal energy travels from hot to cold, so we lose heat from inside to outside in cold seasons and lose our cool during summer as heat makes its way to come inside.
Insulation’s job is to slow down that transfer of heat. R-value is a measurement of a material’s ability to resist the transfer of energy; as we all know, the higher the R-value, the more effective the insulation. In general, each roof and wall design and its energy analysis is the only way to find the right balance between the type of insulation, cost-efficiency, long term energy saving and environmental impact. Below you can find an insulation chart showing the relation between the type, the thickness and the R-value they meet.
What type of insulation should be used?
There are various types of insulation products. Most of our customers choose to go with Fiberglass material insulation which is the same type of insulation you find in many conventional homes. As shown in the chart above, at a thickness of 3 ½”, it provides a range of R-13 to R-15 insulation. Also Mineral wool (sometimes named Rock wool) insulation is popular and provides almost similar R-value like the Fiberglass. They are also relatively cost effective.
But there are more efficient insulation methods, such as Polystyrene Foam boards and Closed Cell Spay Foam. The latter provides the highest insulation value as shown in the chart and completely covers all surface of the corrugated shipping container walls and unlike fiberglass and polystyrene board method, you would not find any gaps between the insulation and the container’s wall. It is very effective at managing air leakage.
But Closed cell uses HCFCs as blowing agent and are poisonous and environmentally hazardous. There is another option, open cell foams that have lower R-value in compare to closed cell but are less hazardous to the environment and it is gaining quick popularity among builders. Closed and open cell foam are relatively expensive methods, but reduces risk of condensation and moisture developing in the gaps between surfaces.
As said earlier, each homeowner should specify the preferable insulation method taking the cost, environment, R-value and energy saving into account.
However, regardless of the system you choose, the structural framing has a significant impact on insulation performance. For internal insulation, either wood or steel studs are on 16” centers, and the insulation material is fitted in the gaps between the studs. But the Fiberglass and Mineral wool do not cover the studs and from that point, a thermal bridging might take place. But polystyrene boards and spray foam cover the studs as well thus managing an even better conditioning inside the structure.
There are other types of insulation, similar to the above-mentioned methods but with different type of materials, such as magnesium silicate, Icynene water-blown, Biobased 1701 and Structural Insulated Panels (SIPs) just to mention few. The latter eliminates the conventional framing approach and provide a faster and very tight closure. There are also eco-friendly insulations such as wool and cotton insulation.
How is insulation of shipping container home accomplished?
After all cutouts and reinforcement has been done, the interior work begins. As standard shipping containers are not finished internally, a framing of wood or steel is fitted just behind the container’s walls. In order to avoid any type of thermal bridging, the studs should be fitted within the structure but not connected to the external walls. Unfortunately, some companies and builders do not stick to this rule and connect the studs to the external walls to ease their job.
Following installation of studs, the insulation material is fitted or sprayed between the studs and even between the stud and container’s external wall. In case using Polystyrene foam boards, they are secured to the studs.
Then they are paneled over with either plywood, OSB board, gypsum board, Aluminum board, MgO board or FPR (Fiberglass reinforced panels). Among these options, MgO board is highly recommended due to its several advantages such waterproof, fire proof, sound proof and bug proof.
Whatever panel covering we choose, it can then be painted or covered by wall papers or be decorated as per any preferred interior design style, very similar to interior walls in conventional homes. The ceilings are insulated similar to the walls.
Nowadays, several companies have developed their own insulation brand based on the mentioned materials. Owens Corning, Demilec, |CertainTeed, Advanced Fiber Technology, Thermafiber, Air Krete, Second Nature, BioBased 1701, and Bonded Logic are some just to mention.
As a result, I’d recommend fiberglass batts or blankets coupled with an excellent sealing job for affordable shipping container houses. In case of building as LEED and provide best insulation for sustainable shipping container home, I’d recommend BioBased insulation as a high-performance option.
Written by: Mashal Jesse