Surfactant Leaching

Surfactant Leaching

As New England Summers gradually move forward and the calendar advances, there is a phenomenon that occurs with painting outside which is often a head scratcher when it is seen and can lead to various forms of panic.

Annually we tend to receive at least a couple of calls where Clients reach out to us with concern that something “weird” is happening with their paint.

This “weird” occurrence (when it happens) is frequently noticed on mid to darker toned colors – though can surely happen on lighter colors!

Its appearance is such that it looks like the paint is reacting in a type of odd way in the formation of brownish and/or glossy (even amongst flat finishes) spots that are tacky and/or oily to the touch.

When someone first sees this, horror may set in as their mind can start to race and thoughts of having to completely repaint something that has just painted can race through the observer’s brains.

Fortunately this type of situation is an extremely easy fix.


Years ago however, I was one that experienced said anxious alarm as I received a frantic call from a Client relaying their concerns.

My guess is the year had to be 1995 or 1996.

We had just completed the project and the homeowner said that they were frazzled because what looked extraordinarily beautiful one day, was covered by this weird brown streaking the next and they were not sure what caused it or what to do.

At the time, neither was I.

I reached out to my manufacturer’s paint rep and set up a meeting at the site.

As soon as our rep put eyes to the issue, he calmly let me know what was occurring.


When latex (water-based) paints and stains, at certain periods of the year (often as Summer wears on and heads into and through Fall) are in their curing process after they are applied and are mixed with the natural moisture that can occur overnight or with rain in conjunction with other weather influences, this circumstance known as ‘surfactant leaching’ can take place.

Surfactants are ingredients in paint that are water soluble and can be brought to the surface of paint coatings (‘leached’) as curing conditions are slowed down if moisture (something as simple as overnight dew) lays on the paint surface.


Although if the conditions are there, surfactant leaching can take place interiorly as well (most often in bathrooms or interior environments with a higher humidity level), I have mostly run into it on the exterior.

The way my rep explained it at the time, the surfactants are very similar to the surfactants one would find in soap (hence their oily feel).

The fix for a situation like this is to do either one of two things.

If one was to gently wipe the surfactant leaching with a warm, wet rag, it will absolutely come off.


My preference however has been to encourage homeowners to let nature take its course as over time, the surfactant leaching will certainly go away as the paint cures and begins to form up its permanent barrier to weather.

Although definitely unsightly, all is not lost if one is to experience surfactant leaching and (as with many things) patience can be an absolute virtue in waiting for it to work its way out and your paint coating to naturally mold itself to the pinnacle of its beauty – which was envisioned when the paint color was first decided upon.

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