Masonry Magazine November 2002 Page. 31
Unlike polyurethanes which expand when installed and bond to adjacent surfaces, foams will pull away from the cavity surfaces to which they are attached.
Before foaming, test samples should be weighed to determine the proper density.
Intermittent extreme temperatures have proven to have little, if any, effect on the product.
During the curing process that takes place after urea-formaldehyde foams are injected, some shrinkage will take place. Unlike polyurethanes which expand when installed and bond to adjacent surfaces, foams will pull away from the cavity surfaces to which they are attached. Most manufacturers specify a linear shrinkage of one to two percent. When shrinkage occurs, it is relatively uniform on all sides. The key to minimizing shrinkage is to install the foam in a cavity where it will dry slowly. Just like a wool sweater in a dryer, rapid drying will cause more shrinkage.
Another cause for shrinkage is too high a ratio of foaming agent with catalyst to the resin. By increasing the foaming agent, which has a low (acidic) pH, beyond its recommended level, the installer could experience excessive shrinkage or degradation of the finished material.
The closed core of a concrete masonry unit (CMU) is the ideal environment for the foam. While there will be a slight amount of shrinkage, it will aid the leaching of water down the side of the cell walls to the base of the wall. The shrinkage does not detract from a favorable performance by comparison to all other pre-cut or poured granular insulation materials used in the cells.
Emissions
EVER SINCE formaldehyde issues were raised by the CPSC, and later discounted in the late '70s and early '80s, there have been few incidences where this subject has resurfaced. Manufacturers have minimized the levels of formaldehyde in the mixed and cured product to approximately .03.05 percent. This is such a low level that it is unlikely that any odor problems could occur, even for the most sensitive individuals.
Up to 120% more thermal resistance than foam board!!
Good
PolyMaster™ R-501 aminoplast foam in the block
R-12.85 in an 8-2-4 wall design
* Highest R value in its class
* 42% more thermal resistance than foam board
* Environmentally green
Better
Incylthane™ 2 lb. urethane spray foam
On the block
R-10.99 in an 8-1-1-4 wall design
* One-step waterproofing and insulating
* Easy installation
* Seamless building envelope
Best
PolyMaster™ R-501 aminoplast foam in the block
And
Incyithane™ 2 lb. urethane spray foam
On the block
R-19.85 in an 8-1-1-4 wall design
* Waterproof
* 120% more thermal resistance than foam board
* Total building envelope seal
* Great savings on HVAC equipment and operation!
Find out what the buzz is all about!
Call 1-800-580-3626 today!
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PolyMaster
The Voice of the Mason Contractor
November 2002
Masonry 29