Commercial Painting Problems & Solutions: Moisture Bubbles

Moisture is one of the largest hazards in most construction environments.  And coatings are no exceptions.

As you can see from the picture, moisture bubbles beneath the coating are unsightly, and they can trap moisture, causing damage to the underlying substrate.  But their origins are a common mystery.  People will pop them, but to their dismay, the bubbles will return with a vengeance.  So where are they coming from, and what can a person actually do to prevent them from returning?

But the Secret’s Out: Moisture is the Issue.

So how can moisture effect the coating?  There are many ways.  But when moisture gets between the coating and the substrate, that’s when you start to have problems.

If the substrate is wood, then moisture can easily travel through untreated wood.  Wood is very porous, allowing many paths and routes for moisture to travel.  But not only does passing moisture cause an issue, but swelling wood can also cause an issue.  When the wood absorbs too much water, then it can swell, causing the surface to expand beyond the cured coating’s elongation capacity.  And then all this expansion and contraction can cause the coating to reach its breaking point.

So, as we know that moisture is the cause for coating bubbles and failure in industrial and commercial painting settings, we need to find ways to prevent that moisture from breaching the areas we don’t want it to breach.

Here are some preventive ways to cease moisture from breaching:

  • caulk all joints, buttes, and anywhere else where there are two adjoining substrates
  • seal the opposite side of the substrate.  If dealing with wood, then seal the other side of the wood, to prevent moisture from penetrating into the opposite side.
  • inadequate drainage.  Potable water can bleed through permeable coatings, accessing the substrate.

When examining the commercial painting, you’ll need to observe for sources of moisture.  Carefully inspect the windows and trim.  These are areas the should be adequately caulked.  If they are not, then they can prove to be access areas for moisture.   Or if the existing caulk looks cracked, or damaged, then moisture can easily access those broken caulk beads.

You Found The Moisture Source, Now What Paint To Use

If you are witnessing moisture bubbles on the surface of the coatings, then you’ll want to address where the moisture is coming from.  Use the techniques listed above to identify the areas.

But after you’ve identified the area, you’ll want to scrape off the old coatings.  Once the old coatings are removed, you’ll want to add a breathable coating to the surface.  A breathable coating will allow moisture to pass through the coating, so that it doesn’t get trapped, and build pressure.

Elastomeric coatings are excellent because they are permeable, and very flexible.  So if the surface expands and contracts, then the coating will flex with the expansion.  Additionally, the moisture will be able to pass through the coating, because it is permeable.

But if you’d like a less expensive option, any latex acrylic paints can be serviceable products in these situations.