When I was a kid, I discovering those self-adhesive cork squares that you can glue to the wall to form a bulletin board of any custom size as long as that size was in even foot increments since that was the size of the cork tiles. I remember thinking this was a great way to hang stuff on my wall like my parents wouldn’t let me do. So I stuck several to the wall of my closet and started my own bulletin board. My father was not nearly as excited about the addition to my room since the squares were backed with an adhesive that never let go, ever. No more self-adhesive bulletin boards for me.
Seems the green building industry is all abuzz this week talking about the announcement of a new type of insulation, cork. Cork is considered to be a renewable resource since it comes from the bark of a type of oak tree grown in the Mediterranean region and can be harvested off of the tree every nine years or so without harming the tree. After wine corks have been cut from the solid stuff, the leftovers are crunched up and mixed with a type of glue to make things like bulletin board squares.
A company in Portugal named Amorim Isolamentos has found a new way to engineer the cork leftovers to come up with a great new renewable insulation. The pieces of cork are ground up and then instead of adding a glue to hold the pieces together the cork is superheated in an autoclave using steam that prompts the cork to release its own natural adhesive that then binds all the little pieces together in nice thick, straight sheets of insulation. The company is offering many different thicknesses from 1” to 12” thick boards either 1’ x 3’ or 2’ x 3’.
So how does this fancy new insulation compare with other insulations? Cork insulation boasts an R-3.5 per inch which puts it neck and neck with a typical fiberglass batt type insulation. One of the major downfalls of fiberglass batt insulation is in how it is installed. Any compression of the batts severely and negatively affects its R value. Since our firm is an inspector of insulation installation jobs with Earthcraft, I can tell you that we almost never sees a grade 1 (perfectly done) fiberglass batt installation job. They are very hard to install so that they work the way the manufacturer designed them to work. The cork insulation, on the other hand, doesn’t have the problem with compression since the cork itself is very strong and naturally resists compression making it much more difficult to install wrong.
Sound attenuation is another bonus with cork insulation. I have installed fiberglass in interior walls before to deaden the sound of the washing machine in my home office which was right next door. What was I thinking designing a house with my laundry room and home office side by side? That is another story. The cork proves to be much better at sound attenuation and you don’t have to only use it in the walls, its compressive strength makes it a great flooring underlayment as well.
You can even install the cork on the exterior of your house much in the same way that builder’s now use foam board to increase overall insulation values. In fact, it can be used as a siding option as well so install it on the outside of your house for insulation purposes and then forget the siding altogether! Want to see some pictures of this stuff in use? Head over to the company’s website at www.bcork.amorim.com and view some of their beautiful photos.
So what about fire resistance? A 40 mm piece of Cork when held over an open flame, resisted igniting for 60 to 90 minutes compared with 10 seconds for expanded or extruded polystyrene. Not bad indeed!
Going back to the bulletin board in my closet, there was always an odor with the cork board, a hard to describe smell, but it was definitely coming from the cork. Whether that was the cork or the glue, I couldn’t tell you. I did read that this insulation has a bit of a smoky smell to it, might be something you would have to see and smell before you buy. Speaking of buying, since this is a brand new product pricing has not been finalized yet. The best bets that I could find for pricing was putting this product at $5.50 per board foot to achieve R-19. That is about 5 times the price of polyisocyanurate insulation. As with any green product, the price drops as the newness wears off and the product becomes easier to get. It’s nice to have options! Let me know what you think at www.gcienergyconsultants.com/wordpress scroll down and comment on the blog.