STEP 8 – Care for Your Newly Painted Exterior
Make sure to check Paints and Stains twice a year, taking the necessary steps as appropriate.
MOLD AND MILDEW
Exterior paints can support the growth of mildew, particularly after they have weathered more than a couple of years. Flat paints, oil-based paints and economy paints are most prone to mildew growth. Is most likely to occur on northern exposure and in shaded and damp areas.
Where mildew is detected:
- Cover plantings and grass in the area.
- Apply a 3:1 mixture of water:household bleach to the mildewed area plus a 1-foot margin, using a brush or garden sprayer; wear eye and skin protection; with colors, do a test area first to be sure the bleach solution will not cause fading.
- Allow the mixture to remain on for 20 minutes; add more as it dries.
- Rinse off the area thoroughly.
DIRT AND CHALK
Airborne dirt can accumulate on paint and darken it, and be a source of nutrients for mildew. Chalky pigment can be released from paint as it weathers, resulting in fading of colors and unsightly rundown. Both dirt and chalk can be removed by scrubbing or power washing.
- Scrubbing is best done with a mild detergent and scrub brush, followed by thorough rinsing. Harsh alkaline cleaners such as TSP can reduce the gloss of alkyd paints and of some latex paints.
- Do power washing with plain water, without the addition of cleaning agents or bleach; use care to not lift paint or damage the substrate. It is an aggressive cleaning method, to be done only when necessary, normally 1-2 times per year maximum.
EFFLORESCENCE
Moisture from within or behind a masonry substrate can carry white powdery salts out, undermining the paint or disfiguring the surface.
- Remove any build-up of efflorescence using a stiff metal wire brush; wear eye and skin protection, and a dust mask.
- If possible identify and eliminate the source of water causing the efflorescence.
- Where necessary, prime with a latex masonry primer and repaint.
CHECK CONDITION
It is important to monitor the condition of exterior paint in order to catch failures early, and thus minimize subsequent failures and make re-do more cost-effective. In addition to assessing exterior paint for dirt, chalk and mildew, and efflorescence, and treating as outlined above, check the paint closely for the following, and repair immediately:
- Cracking or checking
- Blistering, peeling, loss of adhesion
- Serious fading and loss of gloss
- Signs of rusting