green building construction and moldBuilders involved in green building construction tend to believe that using mold-resistant materials will ensure that their building will be free from mold.   Not necessarily! In this segment, we will evaluate materials sold as “mold resistant” used by builders specializing in green building construction.  Many  builders and homeowners with green building objectives tend to equate the mold-resistant material an an insurance against mold.  Let us share with you the results of a casual outing to an outdoor green building festival.

We stopped at two separate booths that advertised bio-based insulation and listened to the company’s representatives.  Along with documentation, we took home two samples of soy-based insulation that according to the manufacturers were “green” and “mold-resistant.”  Both types of insulation are applied by spraying it into walls and attics.

Simple Kitchen Experiment

When we arrived home, we decided to conduct a little experiment.  We put both samples into a bowl of water.  Our primary objective was to learn whether they were truly “mold resistant.”  Our salad bowl was not fancy laboratory apparatus, but it gave us the information we were seeking, and more!

Figure 1 shows our two samples.  Sample A insulation was compact and hard to the touch, while Sample B insulation was spongy and could even be folded in two.

Soya based insulation

Figure 1

We then cut a piece of each sample and dropped them in the same bowl.  Sample A floated while Sample B soaked up water like a sponge and was submerged. Regardless of what we were going to find about their mold-resistant property, we immediately knew by their behaviors, that Sample B insulation would be big trouble.  Two days later we took them out of the water and squeezed them to see how much water we could get from each. A tiny drop of water came out of Sample A insulation, while water contained in Sample B insulation could be squeezed out like a sponge. Figure 2.

Soya based insulation comparison

Figure 2

We put them back in the salad bowl.  Two weeks later we observed a brownish stain on sample A, while sample B remained pristine. Figure 3.

stain comparison on soya based insulation

Figure 3

We then submerged sample A by holding it under water.  The brownish stain disappeared immediately.  We reasoned that the slight discoloration we had observed was simply a color residue.  Had it been mold the substance would not have washed away because of hyphae, the root system of mold that would have anchored itself to the material.  We kept both of them in the bowl for another two weeks and saw no changes. We concluded that they were both, indeed, mold-resistant!    But, let’s not yet hand out the cigars, …

In Part 3 of the Green Building Construction And Mold, we will learn something more about these two samples.

Written by Charles & Danielle Dobbs – Professional mold assessors, expert witnesses, authors of several books on mold, and mold education bloggers

Charles & Danielle Dobbs - Professional mold assessors, expert witnesses, authors of several books on mold, and mold education bloggers

Professional mold assessors, expert witnesses, and authors of MOLD MATTERS- SOLUTIONS AND PREVENTION, MOLD PREVENTION TIPS FOR THE GREEN BUILD INDUSTRY, and INSPECTION AND SAMPLING METHODOLOGIES FOR TRAINING MOLD ASSESSORS.

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