Can I Just Paint Over the Mildew on my Siding?

So, you’re finally ready to freshen up your siding with a coat of paint on your NJ home. There’s only one problem. Over the years your home has been growing some colors of its own: green mildew. And now you’re faced with a dilemma…

“Do I really need to clean this off first?” 

We understand the temptation to just let it be. After all, out of sight out of mind, right? But in this case, you definitely need to deal with it. Here’s why.

The Short Answer: You Can Ignore It, but You Shouldn’t 

As the old adage goes, just because you can, doesn’t mean you should. 

Mildew is a living organism that thrives in moist environments, and painting over it doesn’t eliminate the problem—it conceals it temporarily. If mildew is not properly removed before painting, it will continue to grow and spread underneath the paint layer. This can lead to some unsightly consequences:

• Peeling
• Bubbling
• Premature paint failure 

And on top of that, mildew can compromise the paint’s adhesion, meaning that even a high-quality paint job will not adhere properly. 

How Do You Get Rid of Mildew on Siding?

Let’s get practical with a few tips.

Use a Mildew Cleaner: Start with a commercial mildew cleaner designed for exterior surfaces. Simply apply the cleaner to the affected areas, following the manufacturer’s instructions, and rinse thoroughly.

Homemade Cleaning Solution: You can also use diluted bleach. A mixture of bleach and water (typically a 1:3 ratio) is a tried-and-true method for killing mildew. Apply the solution with a spray bottle or pump sprayer, let it sit for about 5-10 minutes, then rinse off with clean water. Remember to wear gloves, protective eyewear, and old clothes!

Power Washing: High-pressure water spray can blast away mildew and other debris, but it does put your siding at risk of damage. Using too much pressure can unlatch or even break it, forcing water into your home. 

Scrubbing: For smaller areas or particularly stubborn mildew patches, scrubbing with a soft-bristle brush and a mixture of water and detergent can be effective. This method requires more elbow grease but allows for precise cleaning without the risk of damaging the siding. Keep in mind harsh scrubbing with lots of detergent may wear the paint a little but if you are planning on repainting anyway it shouldn’t be an issue. 

How Else Can You Prep for Exterior Paint?

Mildew cleaning is one important area of paint prep but it’s not the only one. 

Clean the Whole Surface: Even if mildew is not a concern, cleaning the entire exterior surface is a must. Dirt, grime, and old paint residues can all prevent the new paint from adhering properly. 

Have Damaged Areas Repaired: Inspect the siding for any cracks, holes, or damaged sections. Addressing these issues before painting ensures a uniform appearance and prevents further deterioration.

Make Sure the Surface is Primed: Applying primer is a crucial step, especially if the old paint has been removed or if the surface has been repaired. Primer helps seal the surface, improves paint adhesion, and provides a consistent base color for the new paint. 

Should I Hire a Professional to Clean or Paint? Or Both?

Before we go, let’s address the other question on many homeowners’ minds: when to call in the professionals. Let’s look at this first for cleaning, then for painting. 

Exterior Cleaning: Some homes are small enough to easily tackle DIY style. But when it comes to larger properties the job gets more complex – sometimes dangerous. Even with DIY long range hose connections you won’t be able to reach the highest points, so in that case it’s best to call a professional. 

Exterior Painting: Painting is different. Unlike cleaning mildew, painting is much more risky and has the potential to result in expensive mistakes. When you hire a professional painter, you are not just paying for a high quality finish but the assurance of a high quality finish. 

What’s the Takeaway?

The takeaway is clear: never paint over mildew. Your home is an investment and deserves the best treatment. By cleaning, preparing, and getting professional help, you can ensure your home looks like a fresh paint job for years to come!  

Don’t want to deal with paint or prep? Brennan Contracting can do it for you! We’ll make sure the job is done right. The whole job.