Cork is a very versatile material with a great green pedigree. It is considered a rapidly renewable material because the bark of the cork oak can be harvested without killing the tree, allowing repeated cycles of production over the 200+ year lifespan of the tree. While cork has long been an attractive choice for flooring, it is now being used to provide building insulation boards, as well.
Like cork flooring, the cork insulation is also made from granules of cork that are left over after wine corks have been punched out of the bark. Cork granules are treated under heat and pressure to release a natural binder and produce billets of expanded cork which are then cut to size. The expanded cork has an R-value of 3.6 per inch. This isn't as good as the highest performance materials, but is comparable to fiberglass batts, cotton (blue jean insulation), and cellulose insulation.
Expanded cork insulation at present is a comparatively expensive material for insulation. The cost comparison from Building Green (who have an extensive write-up of the material) indicates that cork might be as much as 5 times the cost of a similar amount of polyisocyanurate insulation board, and more than twice as expensive as extruded polystyrene. But the cork does not rely on petrochemicals for its manufacture, and offers an all-natural insulation product that will definitely appeal to some builders and building owners.
In addition to its energy performance, the cork insulation is also highly flame resistant, helps with sound absorbtion, and does not offgas any significant VOCs. From a LEED perspective, it is a very useful material, qualifying as a rapidly renewable material in addition to being manufactured from the waste byproduct of the manufacture of another product (wine corks). Many cork forests are already FSC certified. And, from the perspective of a materials red list, it is 100% natural.
via: Jetson Green
written by HotTubWorks, October 17, 2012
written by Francisco Simoes, November 07, 2012
written by Green Business Watch, December 03, 2012
|< Prev||Next >|