Tyvek‚ the wrap from which waterproof express-mail packages are made, is being tested by DuPont as an insulation that could help eliminate mold problems in school walls.
Excelsior Elementary School, which just opened in Grant Bay, Calif., had its interior walls wrapped with Tyvek before they received their final plaster coating. If the experiment proves successful, it could revolutionize the school construction and renovation process.
The solution came about through the determination of Ron Feist, superintendent of the Eureka Union School District, where Excelsior is located. “We have schools in this state dying a slow death with moisture problems,” Feist said. “Some districts have had to evacuate entire schools because of mold and moisture. It’s a huge issue.”
In the construction project, Tyvek Commercial Type(tm) is replacing grade D and grade B insulation paper, which is normally wrapped around the plywood walls to help prevent rot.
“The code called for a double layer of grade D black,” said Corey Price, inspector of record with the California Division of State Architects, “but we knew that wasn’t going to work because it wasn’t working elsewhere [in the state]. Then we considered grade B paper. It has a waterproof designation, but that lasts only a few years.”
Lumber used in construction of school walls appears to be the genesis of the problem with mold in schools, Price said: “The [building] code allows for the use of non-kiln dried lumber. That lumber already has a high moisture content and the presence of mold spores.”
Because the wood does not dry out completely, the spores lie dormantjust waiting for the right combination of additional moisture and warmth to start grow ing.
Since the project is merely an experiment, California’s construction code has not been changed to allow Tyvek on a ongoing basis. However, Price said he would support the change if mold problems are reduced. “We need to re-think the materials we were using and the way the walls [are] constructed,” he said.