A greener take on insulation
A sound insulation is a must to reduce carbon emission and build environmentally friendly buildings. Materials used for insulation, on the other hand, can be hazardous to nature. So, why don’t you grow mushroom in your walls?
In US insulation industry will grow to be a 9.8 billion dollars market by 2020. At the moment insulation materials made of fiberglass dominates the market with a 70% share. Second comes the Expanded polystyrene or SIPS. But neither of them is that eco-friendly.
Fiberglass or glass wall, although is the most conventional material, can be irritating to the respiratory system or the skin, therefore should be purchased as encapsulated, ie. wrapped in bag - not to touch or breath. Moreover, fiberglass is weakest when it is cold outside. The R value decreases considerably when there is air ilfiltration and it is not a steady state environment (from R – 19 to R – 4, for instance)
Structural insulating panel, SIP, is a sandwich of two layers of structural board and an insulating layer of foam in between. The board can either be sheet metal or oriented strand board and the foam can be expanded polystyrene foam (EPS), extruded polystyrene foam (XPS) or polyurethane foam.
SIPs are often recommended for the fact they they can perform better in colder weather and prevent air leakages more effectively; however, many foam insulations are made of petrochemicals and their production causes a restrain on unsustainable resources.
Moreover, “Plastics are a contaminant that goes beyond the visual,” quotes Rachel Ehrenberg, (Styrofoam degrades in seawater) from Bill Henry from the Long Marine Laboratory, University of California, “some of the first evidence of polystyrene as a potential contaminant to wildlife that’s more on the molecular level.” It is not surprising since discarded polystyrene does not biodegrade and is resistant to photolysis. According to the California Coastal Commission, it is now a principal component of marine debris. This material can be harmful to animals if it is ingested by them.
HOW TO GO GREEN IN INSULATION?
As AIA ARCHITECT David Hertz, says that mass produced insulation affects the environment negatively, and instead of styrofoam or fiberglass, we can look for more eco friendly options. He mentions straw-bales, cotton and wool, to which we can include green roofs and even mushroom.
Straw-bale insulation
Straw-bales can be used in natural building as structural elements or for insulation. It can be preferred for its relatively lower costs, availability and significantly high insulation value. The straw-bale walls absorb the sun when it’s out and radiate heat when it’s dark. Unlike what is generally thought, Canadian and U.S. materials laboratories have found that: “The straw bale/mortar structure wall has proven to be exceptionally resistant to fire.” In these tests, the flames took more than two hours to penetrate the plastered bale walls. These bales are very thick, 24 inches of straw bale can have a R-Value up to R-50; but you it works if you have enough space.
Cotton insulation
Cotton insulation is outstanding as an eco-friendly option with a higher R-Value than most fiberglass batts. The cotton is primarily recycled industrial scrap, so it provides a sustainability benefit. The batts do not use the toxic formaldehyde backing found in fiberglass, and the manufacture requires much less energy than fiberglass. Its airborne fibers don’t cause cancer risk.
Wool as an insulation material
The insulation material made from bonded together sheep wool is often used in timber-frame buildings. It is a natural insulator because its crimped nature traps air in millions of tiny pockets. Sheep wool insulation has an higher R – Value than fiberglass, cellulose, or mineral wool. This moisture absorption is unique to sheep wool and does not compromise the wool’s insulating abilities. If it is not going to be recycled, can be composted without causing harm to the environment.
The major drawback is that sheep are often treated with insecticide and fungicide. Sludge, a byproduct of washed off residues on the fleece contains remnants of the pesticides which cause a concern for disposal.
Green Roofs & Living Walls
If you have the chance to have a green roof or green wall, they will also provide you with good insulation. Green roofs serve several purposes, from creating a natural habitat to absorbing rainwater, from providing insulation, to helping lower the urban air temperatures if concenterated in city environment.
Mushrooms
Two young entrepreneurs called Eben Bayer and Gavin McIntyre invented a strong, low-cost, biodegradable and renewable insulation material out of mushroom that could replace the conventional materials.
They noticed that the vegetative roots of mushrooms (mycelia) resemble bundles of white fiber. Placed inside a panel after 10 to 14 days, the mycelia develop a dense network. The panels are dried in an oven at between 100° and 150°F to stop mycelia growth.
Mixed-in seed husks, the mycelia can withstand a blowtorch. It can grow at room temperature and in the dark, doesn’t require expensive manufacturing equipment, and can easily be tailored to different levels of strength and flexibility.
The insulation type most appropriate for you depends on your unique needs and priorities. The optimum can be a combination of two or three for you. David Hertz also recommends installing radiant barriers. A radiant barrier reflects radiant heat energy instead of trying to absorb it and it supplements any of the insulation methods that you prefer to have.
