We don't have many brick homes around here in central Vermont. I recently visited a one-story ranch home that was built with exterior walls of hollow core CMUs (concrete masonry units), a brick exterior and a sheetrocked interior that is strapped to the CMUs, which are filled with vermiculite insulation. I am looking for advice from auditors who have experience with this type of construction. Would you feel comfortable doing a BDT (blower door test) that depressurizes the house? What concerns would you have about this?
Any chance of asbestos - it is an automatic no thanks
Have you thought about pressurizing the house instead
If the drywall is in good shape, you should have little worries about the 50pa depressurization moving fibres of asbestos through the CMU and the drywall into the house. You could also do a Pressurization test and eliminate that.
What was the insulation in the attic? I am assuming not vermiculite since you didn't measure it. If so then no blower door testing until removed.
Finally, how did you determine the presence of vermiculite in the cores of the CMUs.