Paint is peeling or bubbling on a commercial wall

Paint blisters and peels because something has broken its grip on the wall. In Miami the first suspect is moisture, either coming through the wall from behind or sitting trapped under the coating. The second is a surface that was never ready to be painted: dusty, chalky, glossy or previously coated with something that would not bond.

So the first job is to decide which one you have, before anyone talks about a repaint. If the wall is wet or has been wet, the paint is a symptom and the cause has to be found. If the wall is dry and the paint simply let go, it is a coatings job and a straightforward one.

Read the pattern

Where the paint has failed says a good deal about why. Walk the wall and note the position before touching anything.

• Low on the wall, within a meter or so of the floor: moisture from the slab, a splash zone, irrigation spray or a drain that overflows onto the footing.
• Under a window, along a parapet or beneath a roof edge: water getting in at a seal, a flashing or the roof itself.
• Beside a restroom, kitchen or air handler wall: a pipe, a drain line or a condensate leak inside the wall.
• In sheets across a large flat area, with no link to water: adhesion failure from preparation or product choice.

Photograph it with a coin or tape measure for scale and note the date. If it is spreading, that record is how you will know.

Peel the edge and look at the back

Lift a loose flake and look at both sides. If the back of the paint is damp, stained or carries a white crust, water has been behind it. If the back is clean and dry and the wall under it is clean, the bond failed on its own. Dust, grease or a glossy old coat left unabraded will do that.

Press the bare wall with a fingertip. Drywall that is soft, powdery or crumbling has been wet for some time. On masonry and stucco, white salt deposits mean water is traveling through the wall and drying at the surface, and the salt itself will push new paint off.

Humidity and the chalk factor

Miami adds its own causes. Exterior paint that has chalked, leaving a pale powder on your hand when you rub it, no longer gives a new coat anything to hold. Stucco that is painted before it has dried properly holds water behind the film. Mildew under the paint on a shaded elevation also lifts it. Our piece on repainting a commercial exterior in Florida covers intervals and what the climate does to a coating. This article is about the walls that fail well short of the interval.

Inside, the usual culprit is air conditioning that cannot keep up. A cold wall in humid air collects condensation on the paint, and coatings bubble where the drying never finishes. If the building smells damp as well, the article on a musty smell with no visible water explains how to find the moisture that is not showing itself.

Rule out the seal before the paint

A good share of exterior peeling starts at a joint. Caulk around windows, door frames, control joints and penetrations dries out and splits in the sun, and water follows the gap into the wall. The paint fails in a line that follows the joint, which is a useful clue. Replacing that sealant is part of the repair, and our notes on commercial caulking and sealing cover when to renew it. Paint applied over a split joint fails again along the same line.

What to do before repainting

Fix the water first, then let the wall dry, then paint. Drying takes longer than people expect, particularly on masonry in summer, and a surface that feels dry to the hand may still hold moisture inside. Where there is any doubt, leave it, recheck after a dry spell and see whether the bubbles return.

Once the wall is sound, the sequence is straightforward. Scrape back to firmly bonded paint, feather the edges, remove chalk and mildew, patch what is damaged, prime bare areas with a product suited to the surface, and recoat. Where only part of a wall is touched, matching the paint over a repair decides whether the patch shows.

Who carries this out

Scraping, preparation, patching, caulking, sealing, priming and painting, inside and out, are performed directly by our own technicians under our commercial painting service. TrionX carries general liability and workers' compensation on that work, and none of it requires a Florida contractor license. Pressure washing before a repaint is part of the same scope.

If the diagnosis points to a leaking pipe or drain, a condensate line or an air handler, that is plumbing or HVAC work, and the roof or flashing is roofing. Florida requires a license for each of those at any job size. Licensed, insured contractors carry that work out, and TrionX coordinates it and documents it. Water damage that reaches the drywall is repaired by our technicians once the source is closed. If the framing or structure behind the wall is affected, that goes to a licensed contractor as well.

When it cannot wait

Bubbling that is growing week to week, paint that is wet to the touch, a stain that is spreading or a wall that has gone soft needs attention now, because the leak behind it is still running. Flakes on the floor of a customer area, or paint falling from above an entrance, are a housekeeping and liability point as well and should be cleared and recorded right away.

A small area of dry, chalky or tired paint on a quiet elevation can wait for the next scheduled round of work, provided somebody looks at it again and confirms that it has not changed.