Found this old article just today. This stuff would have been perfect, but we seem to be ten years too late. Well, we can always use plain old Styrofoam, which beats everything else we've found so far, except possibly Dryvit. Not even Dryvit matches the performance of this stuff. To make our house as "green" as possible, we need the highest R-value we can manage on the outside of our thermal mass barrier (the concrete wall).
On the other hand, using CFC-11 to manufacture that product is pretty "anti-green"... and if they had gone ahead with the new blowing agent and raised the price even more, could I have afforded to use it at all? hmmm....
Celotex Drops Blackore
Rigid insulation has become increasingly useful as builders strive to boost the R-value of walls. In steel-framed walls, foam is essential to block the massive thermal conductance of steel studs.
Meeting high insulation standards will get more difficult in the coming months because a key product is no longer being manufactured. Celotex Corporation stopped production of its Blackore line of polyisocyanurate insulation board on May 1, 1995. The product will be available only as long as existing supplies last.
Tuff-R Blackore lead the insulation field with an R-value of 8.7 per inch. To achieve that insulating value, Blackore used CFC-11 blowing agent and a special carbon black additive. The additive made Blackore products a bit more expensive than other polyisocyanurate foams, but many builders embraced the product due to its higher R-value.
The extra measure of insulation often allows builders to get just enough insulation to meet energy code or utility program standards. The most common example is walls. Blackore can meet insulation requirements with less thickness, creating fewer problems when securing horizontal lap siding over the foam. Blackore is also handy around the perimeter of ceilings where roof framing can pinch attic insulation.
According to Doug Gehring at Celotex, the company dropped the product when changing from CFC-11 blowing agent to HCFC-141b. The new blowing agent inflicts about 90 percent less damage to the atmosphere's ozone layer than CFC-11. However, HCFC-141b is also more costly. The carbon black additive would have boosted the cost even more. Rather than further increase the price of an already expensive insulation, Celotex decided to drop the product.
Celotex continues to make its other "white core" versions of Tuff-R, Thermax and Sturdi-R for wall sheathing and Hy-Therm for roof applications. These products offer about 15 percent less insulating value per inch than their Blackore counterparts.
The demise of Blackore will leave some builders scratching their heads for new insulation options that meet high standards of energy efficiency.
This article appeared in Energy Source Builder #42, December 1995
© Copyright 1995 Iris Communications, Inc.
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