How to Repaint Wood Siding

Matt Weber

40 minutes ago

6 min read

by Tom Matthews

While a fresh coat of paint may boost a home’s curb appeal, the protection and longevity it adds to wood siding is even more important than the renewed appearance. House paint deteriorates over time, which leads to moisture intrusion and wood rot. Repainting the siding protects it from water, UV damage, and severe weather, and a quality job can last 10–15 years or more when preparation is thorough.

On the project shown, the old paint had greatly deteriorated, and bad caulk joints on the face of the chimney had led to rotted boards in need of replacement. A crew of experienced professionals from Mount Olive Painting (Birmingham, Alabama) handled the repairs and recoating.

This article covers the basic repair, prep and painting approach, which you can apply to your own home. However, the HIR staff advises against working atop ladders at such heights without experience and the proper safety pre-cautions. This is why the homeowners enlisted professionals to paint the upper level and chimney of the home shown.

MATERIALS AND TOOLS

• Exterior 100% acrylic latex paint (preferred for flexibility and durability on wood) and high-quality exterior primer (oil-based or stain-blocking for bare wood, cedar, redwood or tannin-prone species)

• Paint scrapers (pull-style or hooked preferred), random-orbital sander with 80-grit

(and sometimes coarser or finer) sandpaper

• Exterior wood filler or two-part epoxy for repairs, paintable exterior caulk

• Cleaner (TSP substitute, plus mildewcide

or diluted bleach solution if needed)

• Pressure washer (low pressure) or garden hose + long-handled stiff brush

• Airless sprayer, brushes, rollers (medium nap for textured surfaces), extension poles

• Ladders/scaffolding

• Paint shields, drop cloths, painter’s tape, plastic sheeting

• Safety gear: gloves, eye protection, dust mask/respirator (especially if lead paint is

possible on pre-1978 homes)

PLAN & PREP

Poor preparation is the main reason paint fails early (peeling, blistering or cracking).

Work only in suitable weather: ideally 50–85°F (10–29°C), low humidity, no rain forecast for at least 24–48 hours, and away from direct hot sun that causes the paint to dry too fast. Plan for several days of dry weather after washing so the wood can dry fully (often 24–72 hours).

The size of the area to be painted will determine the time required to complete the project, but factor in at least one day for cleaning and pressure-washing, and possibly a second day for simple repairs, such as scraping paint, setting nails, filling fastener heads, and sealing caulk seams.

Calculate the paint required by measuring the wall areas and subtracting openings. Rough or porous wood absorbs more paint. Check the paint label for your product specifications, but a gallon typically covers 300–400 sq. ft. per coat.

INSPECT & REPAIR

Walk the entire exterior. Look for peeling or blistering paint, soft/rotted wood, protruding nails, open joints, mildew or water damage (often near ground level, windows or roof edges). Fix the moisture sources first, such as clogged gutters, high mulch or leaks, or problems will return quickly.

Replace severely damaged boards. Otherwise, scrape away all rot until you reach solid wood, then fill with exterior-grade wood filler or epoxy. Set any protruding nails, fill holes, and sand the filler smooth. Remove any failed caulk and clean the joints.

Lead-paint note: Homes built before 1978 may contain lead. Follow EPA guidelines for

safe work practices if testing confirms it.

CLEAN THOROUGHLY

Cover any plants and the surrounding ground for protection.

Dirt, chalk, mildew and loose paint prevent adhesion of the new coating, so it must first

be cleaned away. A soft-wash is preferred to avoid damage to the siding. Apply the cleaning agent, scrub with a brush, and rinse thoroughly from top to bottom with a garden hose or low-pressure washer. Keep the nozzle well away and the pressure modest, because high pressure can drive water behind siding or gouge the wood.

Allow the siding to dry completely. Never paint damp wood.

Preparation on this project began by washing the walls with a bleach solution and a thorough rinse. When using a pressure washer, proceed with caution to avoid damaging the wood or driving water behind the siding, but a power wash worked well for these vertically oriented 4x8 wood siding panels.

SCRAPE, SAND AND FEATHER

Remove all loose, flaking, or poorly adhered paint with a scraper, working with the grain and keeping the blade flat to avoid gouging. Scrape the lower edges (butt edges) of boards as well.

Sand the rough edges and bare spots with 80-grit paper (random-orbital sander speeds the work). Feather the transition between the old paint and the bare wood so it feels smooth

to the touch. Any sharp edges will telegraph through the new finish and be easily noticeable. Sand bare wood lightly for better primer adhesion. Wipe away the dust.

This home also featured lap siding, some of which was removed for a cosmetic update, and some of which was replaced because it had rotted.

Much of the chimney’s siding and trim had to be completely pried away and replaced with new building materials. Some of the wood siding was salvageable and was repaired using epoxy filler and fresh caulking.

CAULK AND SPOT-PRIME

Apply high-quality, flexible, paintable exterior caulk to the siding’s seams, joints, around windows/doors, and gaps where water could enter. (Do not caulk horizontal joints that need to drain.)

Prime all bare wood, repaired areas, knots, and any areas where the old finish was removed. Use a stain-blocking primer on cedar, redwood, or tannin-heavy woods to prevent bleed-through. Spot-priming is often enough if the existing paint is sound and you’re keeping

a similar color; full priming is recommended for major color changes, heavily weathered

surfaces, or best longevity. Let the primer dry fully per manufacturer instructions.

Any bare wood should first be coated with a high-quality, exterior-grade primer.

APPLY THE PAINT

Apply two coats of quality exterior acrylic latex paint for best durability and coverage. Work from the top down, maintaining a wet edge to avoid lap marks. Paint in the shade when

possible.

The first step is to cut in the edges, grooves, and details with a brush.

The procedure of the Mount Olive Painting crew is to spray-and-back-roll. They spray larger areas and immediately back-roll or back-brush (smaller areas) to work the paint into the wood grain and ensure adhesion. This combination technique gives excellent bonding results on wood.

On the project pictured, the soffit and gutter were painted a contrasting off-white alabaster to contrast the navy blue of the siding.

Professional crews will often paint the trim after the siding if colors differ, masking as necessary.

Always apply thin, even coats rather than one heavy coat. Follow the product’s recoat times. Avoid painting in direct hot sun or when temperatures will drop below the recommended range overnight.

The soffit and gutter were painted an alabaster color, so the crew from Mount Olive Painting began at the top and worked downward. The paint is applied with an airless sprayer.

The concept of painting a house may seem relatively simple at first, but simply reaching the areas of your home that need to be painted is not simple at all -- and access is often the biggest obstacle. Work done at dizzying heights such as repairing a chimney cap is a perfect example of why professional painters earn their money.

The Mount Olive Painting crew applies the topcoat with an airless sprayer as a second painter follows up with a roller, brushing it into the woodgrain for thorough coverage and best adhesion. The workers use a 3/4-inch polyamide roller for the application.

AFTERCARE

Allow the new paint to dry overnight. Inspect it carefully and touch up any thin spots. Allow it to cure fully (often weeks) before aggressive cleaning.

Inspect it annually, and keep vegetation trimmed, gutters cleaned, and moisture controlled to maximize the paint life.

Before and After

Note that, as with all painting projects, proper surface preparation accounts for most of a successful, long-lasting result. Take your time on cleaning, scraping, sanding, repairing and priming—these steps determine how well the new paint bonds and how long it lasts.

SIDE NOTE 1

CONTAINMENT TAPE MAKES MASKING EASY

Need to mask off a paint project? Make the work easier with Frog Tape Double-Sided Containment Tape. First step is to stick the tape right where you need it. As with any tape, burnish it in place—especially on rough surfaces—for the best adhesion. Then, remove the backing strip from the Frog Tape Containment Tape to reveal its adhesive surface. Follow up by unrolling your plastic sheeting over the adhesive strip to anchor it in place. The paint masking is now complete! The two-sided tape works great on borders, around doors and windows, and to seal off rooms from overspray or airborne dust.

SIDE NOTE 2

FOUNDATION PREPARATION

The concrete block foundation got painted too, but the prep steps differ from the wood siding. You can really go to work with high-pressure water on the block, which was necessary to blast away loose paint. (By the way, after a little experimentation, we determined that a rotating “turbo” nozzle does the best job of stripping loose paint from concrete.)

After stripping loose paint with a pressure washer and a wire brush, clean and fill any damaged mortar joints with a reputable concrete/masonry filler product, then prime the repairs and any exposed concrete with an exterior-grade masonry primer prior to repainting.