Pressure treated wood is wood that has been infused with chemical preservatives to help protect it from rot, decay, and insect damage. This treatment allows the wood to last much longer, especially when exposed to outdoor elements like rain, sun, and moisture.
While pressure treated wood is durable, many people prefer to paint it to improve its appearance or match existing painted trim or structures. But before painting pressure treated wood, there are some important preparation steps to take. Here are tips and instructions for properly painting pressure treated lumber.
Should You Paint Pressure Treated Wood?
Painting pressure treated wood is completely optional – the treatment already protects the wood. But there are good reasons you may want to paint it:
- Improve appearance – The chemicals can leave pressure treated wood with a greenish tint. Paint covers this to achieve a more natural wood look.
- Match existing structures – If you have pressure treated wood next to already painted trim, posts, or boards, painting will blend the new and old wood.
- Add another layer of protection – Paint forms a protective seal to further shield the wood from moisture damage.
- Customize color – Paint lets you match any color scheme if the natural green tint of treated lumber doesn’t fit your aesthetic.
As long as proper preparation and paints are used, you can successfully paint both new and old pressure treated wood in any exterior or interior application.
When to Paint Pressure Treated Wood
Pressure treated lumber purchased from the lumberyard will be very wet with chemical preservatives. These preservatives need time to fully dry and set into the wood fibers.
If you paint pressure treated wood before it has dried properly, the paint may peel or bubble. The excess moisture needs an escape path, which pushes through the paint.
Here are general guidelines for drying times before paint can be applied:
- Wood less than 1 inch thick – Allow at least 6 weeks of dry time before painting.
- Wood between 1 to 2 inches thick – Allow at least 8 to 12 weeks before painting.
- Wood over 2 inches thick – Allow at least 4 to 6 months of drying time.
These timeframes assume the wood has been stacked with good airflow on at least one side. Wood left bundled or with poor circulation will take longer to dry out.
Test moisture levels with an inexpensive moisture meter. Look for moisture content below 15% before painting.
If needed sooner, kiln-dried pressure treated wood is available. The intense heat quickly removes excess moisture, allowing paint to be applied after just 2 to 3 weeks.
Prep Work Before Painting Pressure Treated Wood
Proper prep work ensures paint will adhere well to pressure treated lumber. Follow these important steps:
Clean and Remove Mill Glaze
Pressure treated wood can be covered in dirt, oil, wax, and other debris from the treatment and manufacturing processes. Clean thoroughly with a stiff brush and detergent, then rinse well.
The sawing process also creates an impervious layer called mill glaze across the cut surfaces. This needs to be chemically stripped or sanded off to allow paint penetration.
Sand the Surface
Once clean and dry, sand the wood with 80 to 100 grit sandpaper. This roughens the surface for better paint adhesion. Smooth out sanding scratches with 120 to 150 grit paper.
Be sure to wear a safety mask when sanding treated lumber – the sanding dust contains chemicals.
Spot Prime Knots and Stains
Apply a stain-blocking primer to any knots, sap streaks, or tannin stains. Water-based alkyd primers work well. This prevents discoloration from bleeding through the finished paint.
Prime All Surfaces
Priming creates a uniform surface for paint adhesion. Use an oil-based or water-based alkyd primer formulated for exterior wood. Apply according to the manufacturer’s instructions.
Replace Damaged Wood
Inspect for cracked, warped, or rotten boards. Paint will not adhere well or hide underlying issues. Replace damaged pressure treated wood before painting.
Choosing the Right Exterior Paint for Pressure Treated Wood
Not all paints bond well or hold up over time on pressure treated lumber. Consider these factors when selecting paint:
Oil or Latex Paint
Either oil-based or latex (water-based) paints work on treated wood. Oil was traditionally used for its superior penetration, but quality latex formulations have improved greatly.
- Oil-based – Greater surface penetration for excellent adhesion. More durable finish. Long dry time between coats. Contains solvents that can be harmful.
- Latex – Bond well when proper primer is used. More UV-resistant. Shorter dry time. Easier cleanup with water. Low odor and VOC.
For most applications, high quality latex paint will perform well on treated lumber. Make sure it is formulated for exterior use.
Paint Sheen
- Flat – Hides imperfections well but not very durable. Needs frequent touch-ups.
- Satin/Eggshell – Slight sheen, easy to clean. Resists moisture and touch-ups. Good choice for siding.
- Semi-gloss – Durable, smooth finish. Easy to clean. The most resistant to moisture and weather. Good for trim.
Higher gloss gives greater protection but may highlight uneven surfaces.
Mildew Resistant Paint
Mildew resistant paint contains additives to prevent mildew growth. Using this in high humidity areas helps the paint stay cleaner.
Elastomeric Paint
Elastomeric paint (elastomeric acrylic) expands and contracts without cracking or peeling. The flexible resins offer excellent protection from moisture on wood siding or decks.
Application Tips for Painting Pressure Treated Wood
Follow these tips for getting the best results when painting pressure treated lumber:
- Only paint when the temperature is between 50-90°F and humidity is below 85% for proper curing.
- Allow 2-3 hours dry time between coats. More in higher humidity.
- Lightly sand between coats using fine (220 grit) sandpaper for better adhesion.
- Use a high quality brush made for exterior paint. An angled sash brush works well.
- Maintain a wet edge while painting. This prevents lap marks as you reach the end of boards.
- Begin at the top of walls when painting siding and work your way down.
- Backbrush after spraying paint to work it into the wood grain.
- Apply at least 2-3 coats for best coverage and a long-lasting finish.
- Follow manufacturer’s recommendations for any thinning, dry time, and application requirements.
Proper prep work and painting technique allows treated wood to be coated beautifully and protected from the elements. Follow these tips for a paint job you can enjoy for years.
How Long Does Paint Last on Pressure Treated Wood?
With proper preparation and application, painted pressure treated lumber can last from 7-15 years before needing maintenance. Mildew resistant paint may last 2-3 years longer by resisting fungal growth.
Here are factors that affect paint lifespan on treated wood:
Quality Paint
Higher quality exterior acrylic latex paint lasts longer than cheap paint. Invest in paint from a reputable brand designed for wood trim, siding, fences, and decking.
Proper Prep and Application
Taking time to properly clean, prime, and apply the paint leads to greater durability. Rushing the job results in early peeling and wear.
Exposure to Elements
Paint on wood exposed to full sun and heavy moisture will need reapplication sooner than protected surfaces. Overhangs and roof lines see less wear.
Maintenance and Touch-ups
Addressing any worn or peeling paint as soon as it starts extends the life of the overall paint job. Touch up worn areas before they spread.
With the right prep and products, you can expect painted pressure treated wood to last upwards of 10 years before needing a full re-application of paint.
Pressure Treated Wood Paint Colors
Paint allows you to decorate pressure treated lumber in any colors you like. Here are some popular paint schemes for treated wood projects:
Neutral Natural Wood Tones
Painting pressure treated pine in lighter stain-like colors creates a natural wood aesthetic while still providing protection:
- Light brown
- Dark beige
- Gray
- Tan
This allows the beauty of the wood grain to show through while muting any greenish tint.
Bright White
A fresh coat of bright white paint transforms aging gray pressure treated decks, fences, and retaining walls. White reflects sunlight to minimize warping.
White painted railings and trim pop against colorful siding or stonework. Use an exterior white in satin or semi-gloss sheens.
Colors Matching Existing Features
Match fences, trim, and accents to existing color schemes:
- Paint a deck’s railings and pergola to match house trim.
- Coordinate fence and raised beds with exterior home paint colors.
- Paint a pressure treated potting table or bench to blend with garden colors.
Tie everything together with complementary hues.
Vibrant Colors
Tropical climates call for vibrant painted wood to enhance the festive environment:
- Ocean blues
- Seafoam greens
- Sunny yellows
- Coral pinks
Painting outdoor furniture in these fun colors is trendy. Just pick a color scheme and match all accents.
Stained Wood Effects
Specialty opaque stains create a stained wood look while protecting like paint. Consider:
- Rich cedar and redwood tones
- Dark walnut shades
- Weathered driftwood grays
This offers the natural wood tones without revealing the pressure treated green hue.
Painting pressure treated lumber opens up endless possibilities for customizing the wood’s appearance. Choose colors and sheens to match your style.
Maintaining Painted Pressure Treated Wood
While paint protects the wood, it still needs proper maintenance and touch-ups. Follow these tips for keeping painted treated lumber looking its best:
Inspect Frequently
Check painted surfaces at least once per year for any worn, cracked, or peeling paint. Address these areas promptly to prevent spreading.
Clean Regularly
Wash painted wood annually using a high pressure washer (less than 500 psi) to remove dirt, mildew, and chalking. Avoid abrasive cleaners.
Spot Sand and Repaint
Lightly sand any damaged paint edges to feather them smooth. Spot prime bare wood, then repaint just the affected areas.
Full Repaint Every 7-10 Years
Expect a full repaint every 7-15 years depending on wear. Follow all original prep steps before repainting.
Check for Moisture Intrusion
Detect any leaks, cracks, or drips allowing moisture behind paint. Repair these before repainting to prevent further peeling.
Replace Damaged Boards
It’s often easier to replace a badly weathered board instead of prep and repaint. Use matching pressure treated lumber.
With proper maintenance and touch-ups, you can keep painted pressure treated wood looking like new for over a decade. Repair issues promptly to maintain the protective paint barrier.
Frequently Asked Questions
Can you paint pressure treated wood right away?
No, fresh pressure treated wood should dry for at least 6 weeks before painting. The treated lumber needs time to release excess moisture and chemicals.
What kind of paint adheres best to pressure treated wood?
High-quality acrylic latex paint or oil-based paints formulated for exterior wood adhere well. Be sure to prime first.
Do you have to use special primer on treated wood?
Yes, use an exterior wood primer. Oil and latex wood primers work, just check compatibility with your topcoat.
Can you use interior paint on pressure treated wood?
No, only use exterior paint on treated lumber since it faces weathering. Interior paints are not formulated to resist moisture, sun, etc.
How long does painted pressure treated wood last?
Around 7-15 years before needing repainting. Proper prep work, using quality exterior paints, and doing touch ups helps maximize lifespan.
Does pressure treated wood need sealer before painting?
No, priming before painting is sufficient for sealing and preparing the wood. Do not use standalone sealers.
Should pressure treated wood be stained or painted?
Either works. Stain shows off more wood grain but needs more frequent maintenance. Paint provides more protection but hides grain.
Can you paint wet pressure treated wood?
No, only paint properly dried lumber. Wet wood traps moisture under paint and causes peeling/bubbling.
Conclusion
Painting pressure treated lumber allows you to decorate it in any color while providing extra protection from outdoor exposure. With the right prep work, paints, and application, treated wood can be coated beautifully for years of enjoyment.
Be sure to:
- Allow proper dry time before painting new treated lumber
- Clean, sand, and prime the surface
- Use high quality exterior latex or oil-based paints
- Apply multiple coats for full coverage
- Maintain the paint with frequent inspections, cleaning, and touch-ups
Follow these tips for a painted pressure treated wood project that will hold up beautifully against the elements for a decade or longer.