Insulation

Vapor Barrier (Moisture Barrier)

You know how your car has dew on it in the morning? Shipping containers do the same thing. If it’s cold outside, and your container home is warm inside, your container will sweat on the inside of its metal walls. Since weathering steel is designed to create its own oxide layer that protects the underlying steel from rusting, corrosion  from condensation isn’t of much concern. The health implications, however are. Wherever moisture collects, you will find mold, mildew, and even algae. Such contaminants in the air of your home are a health hazard for anyone who has a chronic respiratory disease or asthma. So, it goes without saying that you absolutely must have a vapor barrier of some sort installed before you begin insulating your container home. Here is a list of the types of vapor barrier you can purchase:

• House Wrap–This is plastic sheeting that in normally applied to the outside of a house underneath the siding. When used in a container home, however, it is a good idea to use it on the inside container wall to provide a moisture barrier. If you decide to use this, you will have to apply the adhesive and the house wrap before you frame in the walls. This will give you a hole-free vapor barrier that is sealed against the container wall.
• Closed Cell Spray Foam Insulation–Easily the best option. This option actually serves the dual purpose of providing a superior moisture barrier and the best insulating properties of any insulation type. This will be covered in the next section.

Insulation – There are several types of insulation, each one with advantages and disadvantages. It is of utmost importance to thoroughly study up on insulation types in order to determine which one will be best for your container home. To help you get started, here is a list of insulation types, along with their advantages and disadvantages.

Insulation Types

• Fiberglass Blanket (Batt)
  • Advantages
    • The cheapest insulating material allowed by code.
  • Disadvantages
    • Must be handled carefully in order to avoid crushing it
    • Prone to collecting moisture. This will be amplified in a container home.
    • Provides an environment for mold and mildew growth.
    • Moisture collection in insulation adversely affects insulating properties
    • Allows convection currents to move air through it, adversely affecting its insulating properties.
    • Must wear protective clothing and breathing gear during installation.
• Fiberglass Panel (Batt)
  • Advantages
    • Not as cheap as fiberglass blanket, but still quite affordable
  • Disadvantages
    • Must be handled carefully in order to avoid crushing it
    • Prone to collecting moisture. This will be amplified in a container home.
    • Provides an environment for mold and mildew growth.
    • Moisture collection in insulation adversely affects insulating properties
    • Allows convection currents to move air through it, adversely affecting its insulating properties.
    • Insulating values degrades over time.
    • Must wear protective clothing and breathing gear during installation.
• Loose Fiberglass
  • Advantages
    • Can be blown into spaces difficult to access
    • Insulating properties similar to fiberglass batt
    • Moisture can build up in it, reducing R-factor
    • Mold and mildew can grow in it
  • Disadvantages
    • Must be applied by a professional
    • Costs about the same as cellulose insulation
• Mineral Wool
  • Advantages
    • High R-factor that never degrades
    • Environmentally friendly–95% is wool made from melted stone
    • Acoustic soundproofing properties
    • Fireproof–Withstands temperatures up to 1,000ºC
    • 100% waterproof
    • No nutrient source for mold and mildew
    • Anti-convection properties similar to closed cell insulating foam
    • Actually helps dry out damp spaces
  • Disadvantages
    • Much more expensive than fiberglass insulation products
• Closed Cell Spray Foam
  • Advantages
    • High R-factor
    • Acts as a vapor barrier
    • Never settles or sags
  • Disadvantages
    • Much more expensive than other insulation types
• Cellulose
  • Advantages
    • Environmentally friendly–made from plant fiber.
    • Can be sprayed or blown in
    • R-factor similar to fiberglass batt insulation
    • Acoustic dampening
    • Fire resistant
    • Vapor barrier-like qualities; can help dry out a damp space quicker
  • Disadvantages
    • Dust can infiltrate home during installation
    • Slumping–Settling of insulation due to improper blowing or spraying
    • Weight–Can weigh 2-3x loose fiberglass insulation
    • Offgassing–May give off an ammonia smell

There are other insulation types not included here due to mostly commercial exterior applications.

With so many insulation types to choose from, it can be a bit overwhelming. It may be worth consulting with an architect to help you decide which insulation will be best for your home.

Insulation Installation

Fiberglass Batt Insulation

Batt insulation is installed between the studs. The biggest issue with this insulation type is the likelihood of it becoming saturated with water, which will precipitate other issues, such as reduction in R-factor and the promotion of mold and mildew growth. Furthermore, the rapid changes in temperature caused by the steel container walls will cause convection currents in the insulation that destroy its insulating ability. While fiberglass batt insulation may be the most affordable, it probably won’t be the best solution for your container home.

Mineral Wool Insulation

This insulation is also installed between the studs. Due to its vapor barrier-like characteristics, it can be installed without any concern for condensation or degradation of insulating quality over time. This type of insulation is one ideal for use in a container home.

Blown Insulation

This type of insulation is usually blown in after the interior walls are finished. It may be a good idea to cover wall outlets with plastic before the insulation is blown in. This will help prevent the house becoming dusty during application.

Sprayed Cellulose Insulation

Sprayed cellulose insulation is not recommended due to the fact that it will introduce moisture into a space that has a steel wall. This moisture can remain trapped for an extended period of time, leading to mold and mildew growth. If sprayed cellulose is used, the insulation may need to be dried out using some kind of forced ventilation.

Spray Foam Insulation

This insulation is applied after the walls are framed in, but before hanging the drywall. This is the other optimal insulation for container homes, due to it acting as a vapor barrier while preventing convection currents of air from circulating in the wall space. The foam fills the entire space between studs. Insulating qualities remain the same indefinitely.

Pro Installation

Blow-in or spray insulation should be left to the professionals. There is a significant amount of technical knowledge and skill required for the job to be done right.

Wrapping It Up

There are a lot of insulation options to choose from. There is also a lot to learn about insulation and what will be best for your container home. If it’s all a bit much for you, consult with a reputable architect to determine which insulation will be best for your home.