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4 Ways to Insulate a Container Home

4 Ways to Insulate a Container Home

By Tobias RobertsRise Writer
Apr 24, 2018

Shipping container homes are continually growing in popularity as a sustainable and inexpensive housing option. With over 300 million freight containers sitting empty at ports around the world, the opportunity to expand this innovative and sustainable housing alternative might very well only continue to expand. Also, many real estate experts foresee an increasing synergy between shipping containers as a housing alternative with more traditional prefabricated building options.

However, one of the biggest challenges that shipping container homes face is finding proper ways to insulate the container itself. The $2,000 price tag for a used shipping container might seem like a perfect housing alternative for people searching for an affordable and sustainable home. Although many don't enjoy the thought of living inside a metal box during the hot summer days is not as appealing. Fortunately, several insulation options transform container homes from metal boxes to pleasant and livable dwelling places.

What Are The Challenges of Insulating Container Homes? 

The main challenge of properly insulating a container home is related to the walls' inherently shallow depth. While the shipping container's metal structure is a sturdy and durable wall material, the lack of thickness poses a challenge for correct insulation.

Ryan McCue is the President of Tiny Home Connection, a Colorado-based consulting and construction company specializing in tiny homes. According to Ryan: 

"To get the proper insulation in a shipping container, the walls must be built out to allow the appropriate depth to install the insulation, much like you would when finishing a basement. Unfortunately, this may mean taking up precious square inches inside the container. Otherwise, you could build out the outside of the home. Still, you then remove the aesthetics of the shipping container exterior that many people seem to like."

Before deciding on an insulation material for your container home, you will first need to determine how you want to build out the walls. If you are connecting several shipping containers for a multi-container home, adding space on the inside of the walls might not be an issue because of the extra square footage of the house. If you opt for a tiny homemade from one or two shipping containers, space will be a premium. In this case, you might be better off adding insulation to the exterior and then covering it with some exterior cladding. You can then choose to either leave the inside walls as exposed metal or cover them with some interior plaster.

spray foam

Is Spray Foam Insulation Good for Container Homes?

One of the easiest and quickest ways to insulate a container home is with spray foam insulation. This insulation material can be sprayed directly onto both the interior and exterior walls of a shipping container. Many shipping containers are coated with highly toxic paints to withstand life at sea. Spray foam insulation can trap the VOCs that could off-gas into your home.

However, spray foam insulation is a product of the petrochemical industry, which is not a hallmark of sustainability. Also, the EPA has identified potential health hazards related to polyurethane spray foam insulation, including asthma, lung damage, and other respiratory ailments. In addition, it is important to know that not all spray foam is created equal. Many conventional spray foams have very detrimental impacts on the atmosphere.

Icynene is a water-blown spray foam insulation product that expands as it hardens and thus insulates a home through tiny plastic bubbles that form in the interior of the insulation. While many other types of polyurethane spray foams can off-gas chemicals into your home, the small amount of VOCs associated with Icynene insulation will most likely be completely undetectable between 2-3 weeks. 

When asked about what insulation option his company recommends to their clients, Ryan of Tiny Home Connection said:

"Choose a product that has expansive properties, such as closed-cell foam or Icynene. These come with a higher price tag upfront, but the energy savings over time more than make up for it. These products take much of the guesswork out of insulating and do a much better job of sealing and insulating than other moderately to poorly installed insulation products."
cotton insulation
Cotton Insulation. Photo Credit: Bonded Logic Inc

Is Cotton Insulation Good for Container Homes?

An important ethic of sustainable homes and construction is to try to reutilize as much as possible. Today, several companies offer natural, cotton-based insulation made from recycled, post-consumer denim and cotton sourced from used jeans and other clothing products. 

Cotton insulation has an R-Value of 3.5 per inch, similar to that of more traditional fiberglass insulation. Commercial denim insulation is usually treated with boric acid, a natural fire retardant. 

On the negative side, denim insulation does require a vapor barrier. If it does get wet, it will become dense, lose some of its insulation properties, and take a long time to dry out. UltraTouch is one company that offers denim insulation that is recycled post-consumer waste and naturally VOC-free.

Havelock Wool Sheep's Wool Insulation
Havelock Wool Sheep's Wool Insulation

Is Wool Insulation Good for Container Homes?

Another natural insulation alternative sourced from renewable and natural materials is sheep's wool. This high-performance and environmentally friendly insulation alternative have an R-value of 3.5 per inch, similar to fiberglass, denim, or other fibrous insulation types. The lanolin in sheep wool is a naturally flame retardant, making it unnecessary to treat the wool with other chemical solutions.

Before you go out to sheer a few sheep, several companies are specializing in selling sheep wool insulation products. Companies like Black Mountain offer different varieties, and some even come with natural condensation control. The hygroscopic fibers in sheep wool can absorb up to 35% of its weight in water without altering the thermal performance.

CC by 2.0 Cork
CC by 2.0 Cork

Is Cork Insulation Good for Container Homes?

Cork insulation is another natural insulation alternative for container homes. Cork is a renewable and biodegradable resource from trees. Amazingly, cork trees do not have to be cut down to harvest the cork, but rather the bark from the trees is harvested every nine years. This harvesting process makes cork “carbon negative” since the cork forests (mostly in Portugal) capture carbon from the atmosphere.

The acoustic property of cork is yet another benefit of cork insulation for shipping container homes. This natural insulation material will form an acoustic buffer between your home and the metal walls of the container, which, left alone, would transmit sound easily. Companies like ThermaCork specialize in a wide array of cork insulation products.

Disclaimer: This article does not constitute a product endorsement however Rise does reserve the right to recommend relevant products based on the articles content to provide a more comprehensive experience for the reader.Last Modified: 2021-07-10T04:32:55+0000
Tobias Roberts

Article by:

Tobias Roberts

Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.