If You Suspect Mold in a Building – Remember the Hindenburg!

Lucas Hamilton

If you have had some moisture damage in your building and suspect or see that you have some mold, remember The Hindenburg

Before you cut into the wall, compartmentalize and put the space under a negative pressure.  The last thing you want to do in a building when you think you may have had a moisture issue and suspect that mold could be growing behind the wall is to disturb it and have the mold spores release into the air within the building. If you think you may have a problem and need to cut into the wall take these steps to create negative pressure in the room:

  • Close the door
  • Open a window
  • Put a fan in the window blowing out to create negative pressure in the room
  • Then you can safely cut into the wall to treat the mold

The lesson we learned from the Hindenburg relates to the smoking lounge.  The lounge was kept under positive pressure and the smoke leaked out into the rest of the dirigible so that if there was a gas leak in the envelope of the dirigible, the gas could not flow into the smoking lounge to get ignited by a pipe or a lighter.

You are doing the same thing here but in reverse.  You are putting the space into a negative pressure before you disturb the space so that contaminants could not possibly flow into the building.

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

Tolerance for Moisture Intrusion is a Challenge in Vancouver

Lucas Hamilton

Earlier this week I traveled to Vancouver, British Columbia, Canada to present the workshop on Mold and Moisture Control in buildings at the final [Be Certain] event.  It has been fascinating to present these workshops in different Northern climates and creating simulations to address the specific challenges faced in these areas of North America.

Previously, I blogged about polyethylene in Calgary, Alberta, Canada and the challenges faced in controlling moisture because of the use of exterior insulation. In preparation for my Vancouver workshop, I re-ran the modeling for Vancouver and the results were very interesting.

Polyamide films, like MemBrain™ because it is a breathable vapor retarder can provide additional tolerance for moisture intrusion in many climates, but in extreme climates like Vancouver there is almost no way to survive water intrusion.

In such climates, the best course is to build into the design redundant drainage planes and flash, flash, flash. Expect water to pass your principle line of defense and stop it with a secondary line of defense which will evacuate the intruding moisture to the exterior environment. This would be like a window rough opening being completely wrapped prior to window installation and this rough opening flashing draining water out and onto the face of a water resistive barrier (WRB) which leads to an egress at the base of the wall system.

While there is so much we know about moisture management, there is always more to learn and our thinking must be comprehensive. If we don’t learn from the past, our attempts to build air-tight and moisture-tight buildings will leave us looking more like Wile E. Coyote grasping for the next solution. I am not comfortable with that. Thoughts?

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation