Mold: created from the outside

My maintenance manager and I were looking over a rental house that recently became vacant.  The tenants had lived with mold and never told us about it.  The extent of the mold was large and it re-emphasized our need to do annual inspections.  We normally inspect every house every year.  But this one had slipped through the cracks.  Had we been diligent and done our annual inspection we would have caught the mold early on.mold

But what was really telling was the cause of the mold.  It had grown on various walls, around windows and sills, and really in areas I wasn’t used to seeing.  My maintenance manager immediately offered up the idea that the mold was actually coming from the outside!  Huh?  What’s that you say?  The outside?

We went outside and he showed me cracks in the caulking around the windows.  Water would travel into these cracks and migrate anywhere and everywhere it wanted.  In addition, it was horizontal, cedar siding and many of the butt joints had cracked open, allowing water inside.  The paint on the exterior siding was failing because the siding had not been primed before it was painted.  (Why people paint like this continues to baffle me!).  As the paint was peeling from the wood, it was creating pockets that were trapping water. Simply put, the exterior siding was wet in many places.

The moisture on the outside of the walls and from the cracks was migrating in the wall and creating a moisture-rich environment.  With the warmth from the inside of the house, a healthy crop of mold had sprouted!

It would be easy enough to wash the walls and window sills with vinegar and baking soda, prime, and paint.  Vinegar and baking soda is our non-toxic, effective alternative to the usual bleach approach.)  But this would have been only a temporary solution.  Soon enough the mold would reappear.  The key to mold remediation is to get rid of the source.  That source is almost always moisture, and often warmth.  We can’t and aren’t going to remove the warmth, but we can get rid of the moisture!

We will begin by scraping and wiring brushing all of the old paint off the exterior siding and get down to bare wood and/or good paint.  Then we will caulk and re-caulk around all of the windows, openings, pipes, and other penetrations.  Then we will prime with a good, oil-based primer.  (Always prime bare wood with oil-based primers; never latex.)  After that we will give the entire siding a good paint job — probably spray with a back roll.  Spraying insures good coverage — back rolling insures good adhesion.

Mold is serious business.  To get rid of it you have to do the job right.  Don’t cut corners and you’ll be rewarded with a dry, healthy home.  Cleaning up the mold is step #1.  But beyond cleaning it up, ask yourself why did it grow in the first place.  You may find a water leak you best plug up!

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