Water and moisture, though seemingly harmless, can cause a variety of paint problems. Think you’re experiencing it? Let’s familiarize you with the most common ones and how they’re typically fixed. As always, if you’re unsure, don’t hesitate to consult a professional for guidance. (Tip: You can reach out to the Boysen Technical Service Department as well. Contact details are on the bottom of this blog post.)

1. Blistering

blistering wall paint

How to spot it: Blistering will look like bubbles are forming underneath your paint. Yup, it’s not pretty.

Why you’re seeing it: It’s likely that a water leak somewhere in your home has crept its way to your wall and underneath the paint. The water is trapped inside and causes unsightly bulges. It’s a problem more commonly seen on glossy paint than flat paint.

What needs to be done about it: Scrape off all the blistering areas and repaint. Before that, however, if a water leak is indeed the cause of the blistering, it must first be found and fixed. Otherwise, you’ll get the same problem again even if you repaint.

Learn more about blistering here.

2. Mold and Mildew

mold on painted wall

How to spot it: Mold and mildew will look like fuzzy or slimy dark spots on your wall. It will give the room a musty odor.

Why you’re seeing it: They thrive where it’s moist and humid. So, you’ll likely see it in more humid areas of the home like bathrooms and kitchens. They’re also more likely to pop up during the rainy season.

What needs to be done about it: With a brush, apply a mixture of 1:3 bleach to water to the moldy painted surface. Let it stand for 24 hours before washing off the residue. Periodic maintenance is key. Once mold and mildew have found a home on your wall, they’ll keep coming back!

Learn more about mold and mildew here.

3. Rusting

rusted metal

How to spot it: You’ll notice rust as red or orange spots on metal.

Why you’re seeing it: Rust occurs when metal is exposed to water and oxygen. The best way to prevent this is to cover your metal surface with a good-quality coating to protect it from the elements.

What needs to be done about it: Rust treatment can be tedious work and can involve both manual and chemical solutions. You’ll find the full step-by-step guide here. To avoid going through it in the first place, prevent it by choosing quality primers and topcoats.

Learn more about rusting here.

4. Efflorescence

efflorescence on painted wall

How to spot it: You’ll notice efflorescence as white, crusty- or fuzzy-looking residue on a wall. In Filipino, it’s called umido.

Why you’re seeing it: Where glossy paint has blistering, flat paint has efflorescence. It’s caused by water passing through a concrete wall and then evaporating. As the water evaporates, it leaves behind salt deposits which is what you’re seeing on your wall.

What needs to be done about it: Scrape off as much of the efflorescence as you can. You can also apply a clear coating on the affected area to block moisture. Like with blistering, if a water leak is the cause of the efflorescence, it must first be found and fixed.

Learn more about efflorescence here.

5. Saponification

saponification on painted wall

How to spot it: The first sign of saponification are specks on your painted surface. Saponification will eventually cause the paint to weaken and once it does, it will start to come off your wall and lose its color.

Why you’re seeing it: Simply explained, saponification happens when highly alkaline concrete (alkaline meaning it has a pH level greater than 7) is continually exposed to moisture. Commonly, it arises when an oil-based paint is applied to concrete.

What needs to be done about it: There’s no going around it. The entire surface must be scraped to bare. Clean the surface, wait for it to dry, then repaint.

Learn more about saponification here.

If you have any questions or inquiries about Boysen products, our technical team will be happy to assist you. Send an email to ask@myboysen.com or call (02) 8363-9738 local 413 to 418 during office hours for a one-on-one consultation.


Jill is a writer on a continuous journey to learn about paint and share them with you, the reader. She has an interest in the technical side of things but also thoroughly enjoys playing with colors. She likes calm greens, quiet blues, and mellow yellows best.

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