Professional Touch Painting

Mildew, Mold & Fungus

Mildew is a black or brown fungus that can grow on, and disfigure exterior surfaces, including paint. While it is not possible to guarantee a 100% mildew-free paint job, especially for a long period of time, there are some precautions that can help significantly in reducing or avoiding mildew growth on painted surfaces. Please read this before starting your exterior painting projects.

1. The Environment:

There isn't much you can do about this, but try to keep these factors in mind before repainting and during product selection, so you can say you gave it your best shot in terminating the mildew. Semigloss latex paint helps prolong this problem, don’t use oil-based if you live in a shady area, also warm and moist weather, and absence of freezing weather encourages mildew growth, and mildew in your immediate area leads to mildew growth (windblown spores), protected areas are prone to growth; sunny areas help slow accumulation of mold and mildew.

2. The Surface Being Painted:

Never paint over mildew, you must bleach it first or is will reappear, and don’t just prime over it.

HOW TO: Apply a mixture of water and household bleach, 3:1, and be sure to protect your eyes, skin, and prevent inhalation. Vegetation and plants need to be wet down and/or covered before application of bleach solution to prevent burning and damage. Apply the solution to the surfaces containing mildew allow 20-30 minutes, reapply if it dries, and then rinse thoroughly. For heavy buildup of mildew, bare wood, and areas previously painted with oil-based, you may need to add a scrub brush and some elbow grease. Remember any exterior surfaces containing oil-based paint should be primed and top coated with acrylic latex primer.

3. Mold Preventative Choices:

Latex, of course, is better than alkyd and oil-based paints for exterior mildew, and dulling prevention. Satin, Semi, and Gloss formulas are generally more mildew resistant than flat and low sheen paints. High quality paint likely has a mildacide unlike lower grades, but be sure to consult with your paint rep to make sure you choose products with a mildacide additive, otherwise you will be throwing your time and money away. Don’t be fooled, Benjamin Moore Exterior paints don’t all have a mildacide in their formula. However, all Sherwin Williams Exterior paints have a mildacide additives in their products. Mildacide - an ingredient added to exterior paints helping resists the growth of mildew.

4. Color Selection:

Dark colors attract sunlight, so they will also dry surface moisture like dew and rain much faster, thus darker colors inhibit mold growth. You can buy and a use mildew-resisting additive that comes in a small plastic pouch that the homeowner can mix in their selves, it is available at all paint stores, but only if your paint rep recommends. (Some solvent based latex paints don’t take these additives very well)

5. Paint Application:

Of course, two coats are always better than one, a heavy coat offers more protection than a thin one, a prime and top coat is better that two top coats. Keep an eye on weather conditions, avoid painting when windy most importantly where mildew has been an issue in a certain areas (shady sides of home ect). When at all possible, even if you have to pay a paint contractor, exterior paint should be applied with a sprayer because it will prevent mold and mildew. When exterior paint is brushed or rolled it has lands and grooves that provide a home for organic materials thus helping mold spores and mildew accumulate.

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