If you've ever watched a fresh coat of paint on wood siding start peeling within a year or two, you already know the frustrating truth: paint is only as good as the prep work underneath it. Here in Western New York, wood siding takes a real beating. Between the lake-effect snow, freeze-thaw cycles, summer humidity, and driving rain, a paint job that might last eight years in a milder climate can fail in half that time if the surface wasn't properly prepared.

The good news is that thorough prep work isn't complicated. It just takes patience and the right approach. Whether you're planning to tackle this yourself or you want to know what to expect from a professional crew, this guide walks through every step of prepping wood siding so your paint job actually holds up.

Why Prep Work Matters More Than the Paint Itself

Most homeowners focus on choosing the right color or brand of paint, and those things do matter. But if you apply even the best exterior paint over a poorly prepared surface, it will fail. Paint needs a clean, sound, dry surface to bond to. Skip the prep and you'll see bubbling, cracking, and peeling long before you should.

This is especially true in the Rochester and Buffalo areas. Our winters are harsh, and moisture is the number one enemy of exterior paint on wood. Water gets behind the film, freezes, expands, and pushes the paint right off the surface. Proper prep creates the conditions for paint to grip tight and flex with the wood through seasonal changes.

Step 1: Inspect the Siding Thoroughly

Before you touch a scraper or pressure washer, walk the entire perimeter of your home and look closely at every section of siding. You're looking for several things:

Peeling or flaking paint that has lost adhesion
Cracked, split, or warped boards that need repair or replacement
Soft or spongy wood that indicates rot
Mold, mildew, or algae growth, especially on north-facing walls
Open joints or gaps around windows, doors, and trim
Exposed or popped nail heads
Caulk that has dried out, cracked, or pulled away

Take notes or mark problem areas with painter's tape so you don't miss anything when you start working. If you find widespread rot, that's a bigger conversation about whether sections of siding need to be replaced before any painting happens.

A Note on Lead Paint

If your home was built before 1978, there's a real chance the existing paint contains lead. This is common throughout Rochester, Buffalo, and the surrounding towns with older housing stock. Disturbing lead paint through scraping or sanding creates hazardous dust. If you suspect lead paint, have it tested before you start any prep work. Professional painters who are EPA Lead-Safe certified know how to handle this safely. It's not something to take chances with, especially if children live in the home.

Step 2: Wash the Siding

Wood siding accumulates years of dirt, pollen, pollution, mold spores, and chalky residue from old paint. All of that needs to come off before you do anything else.

Pressure Washing vs. Hand Washing

Pressure washing is the most efficient method, but you need to be careful with wood siding. Too much pressure can gouge soft wood, force water behind boards, and raise the grain in ways that create problems later. Here are some guidelines:

Use a fan tip (25 or 40 degree), never a zero-degree tip
Keep the pressure at or below 1,500 PSI for most wood siding
Hold the wand at least 12 inches from the surface
Work from top to bottom, angling slightly downward so water doesn't get pushed up behind the lap joints
Use a cleaning solution designed for exterior wood or a mix of TSP (trisodium phosphate) and water for heavy grime and mildew

If you're uncomfortable with a pressure washer, you can hand wash with a stiff-bristle brush and a garden hose. It takes longer, but it's gentler on the wood. For heavy mildew, a solution of one part bleach to three parts water works well. Just rinse thoroughly afterward and protect your plants below.

Drying Time

This is where a lot of DIYers make a costly mistake. After washing, wood siding needs time to dry completely before you move on to scraping, sanding, or priming. In our WNY climate, that usually means at least 48 to 72 hours of dry weather. If it's humid or overcast, give it even more time. Painting or priming over damp wood traps moisture and guarantees early failure.

Step 3: Scrape Off Loose and Failing Paint

Once the siding is clean and dry, it's time to remove any paint that isn't firmly adhered. You don't necessarily need to strip the siding down to bare wood everywhere. The goal is to remove anything loose, peeling, bubbling, or flaking so the new paint has a solid base.

Tools for Scraping

Rigid putty knife (3" to 5") for general scraping
Carbide scraper for stubborn areas, stays sharp much longer than steel
Hook scraper or pull scraper for large flat areas
Detail scrapers for tight spots around trim and window casings

Work methodically, section by section. Hold the scraper at a low angle to avoid gouging the wood. Any paint that resists scraping and is still firmly bonded to the surface can stay. You're only removing what's already failing.

When to Consider Full Stripping

If you have many layers of old paint that are alligatoring (showing a pattern of deep cracks that looks like reptile skin), you may need to strip down to bare wood. This can be done with chemical strippers, infrared paint removers, or heat guns. Avoid open-flame torches, which are a fire hazard on wood siding and can release lead fumes from old paint.

Step 4: Sand the Surface

After scraping, the edges where old paint meets bare wood will be rough and uneven. These "feathered edges" need to be sanded smooth so they don't show through the new paint as visible ridges.

Use 80-grit sandpaper for heavy feathering and rough spots
Follow up with 120-grit for a smoother finish
A random orbital sander speeds up large areas, but hand sanding works fine for detail work and smaller sections
Always sand with the grain of the wood, not against it

Sanding also scuffs up any remaining glossy old paint, which helps the new primer and paint bond better. If the existing paint is in good shape but has a sheen to it, a light sanding over the whole surface makes a real difference in adhesion.

After sanding, wipe or brush off all the dust. A tack cloth or damp rag works for small areas. For a whole house, you might use a leaf blower or a quick rinse with the garden hose (then allow drying time again).

Step 5: Make Repairs

Now that you have a clean, scraped, and sanded surface, it's time to deal with any damage you found during inspection.

Replacing Rotted or Damaged Boards

If a board is rotted through, soft to the touch, or badly split, replace it. You can often find matching profiles at local lumber yards. For small areas of minor rot (surface-level only), you can dig out the soft material and fill with a two-part wood epoxy like Abatron or Minwax High Performance Wood Filler. These products cure hard and can be sanded, primed, and painted just like the surrounding wood.

Setting Nail Heads

Popped nails should be driven back below the surface (or replaced with galvanized or stainless steel ring-shank nails) and the holes filled with exterior-grade wood filler. Flush everything smooth once the filler cures.

Caulking Joints and Gaps

Caulk is your first line of defense against water intrusion at joints, seams, and transitions. Use a high-quality, paintable exterior caulk (100% silicone is durable but not always paintable, so look for siliconized acrylic or polyurethane caulk). Apply caulk to:

Joints where siding meets trim, window casings, and door frames
Corner boards and butt joints between siding pieces
Any cracks or gaps that would allow water behind the siding

One important rule: do not caulk the bottom edges of lap siding. Those gaps allow moisture that gets behind the siding to drain out. Sealing them traps water and accelerates rot.

Step 6: Prime Bare Wood and Problem Areas

Priming is not optional on bare wood. Paint applied directly to unprimed wood won't adhere properly and will fail much sooner. Even if you're using a "paint and primer in one" product, bare wood still needs a dedicated primer coat.

Choosing the Right Primer

Oil-based primer is the traditional choice for bare wood siding and is still preferred by many professional painters. It penetrates well, seals the wood, and blocks tannin stains (common with cedar and redwood). The downside is longer dry time and stronger fumes.
High-quality acrylic primer has improved dramatically and works well on most wood siding. It dries faster and cleans up with water. Look for products specifically rated for exterior bare wood.
Shellac-based primer is the best choice for blocking stubborn stains, knots, and tannin bleed-through, but it's typically used as a spot treatment rather than a full-surface primer.

Apply primer to all bare wood, all repairs (wood filler, epoxy patches, new boards), and any stained areas. If the existing paint is in decent shape and well-adhered, you don't necessarily need to prime the entire house. But if you're making a dramatic color change, a full coat of tinted primer will save you an extra topcoat and give you better coverage.

Timing Matters

Don't let bare wood sit exposed for more than two weeks before priming. Sun and moisture will start degrading the surface, and you'll lose the clean, sound substrate you worked so hard to create. If weather delays are likely (a real possibility in Western New York), prime in sections as you go rather than prepping the whole house and then coming back to prime.

Step 7: Final Check Before Painting

Before you open a can of topcoat, do one last walkthrough. Check for:

Any spots you missed during scraping or sanding
Caulk that hasn't fully cured (most products need 24 hours minimum)
Dust or debris on primed surfaces
Weather conditions: ideal painting weather is dry, between 50°F and 85°F, with low humidity and no rain in the forecast for at least 24 hours

This is also when you want to protect areas you don't want painted. Tape off windows, mask light fixtures, and cover walkways and landscaping with drop cloths.

Common Prep Mistakes That Lead to Paint Failure

We see certain patterns over and over when homeowners call us about paint that's failing prematurely. Here are the most common culprits:

Painting over dirty siding. Even if the old paint looks fine, dirt and chalky residue prevent proper adhesion.
Skipping the primer on bare wood. This is probably the single most common mistake.
Painting over damp wood. Whether from rain, pressure washing, or morning dew, moisture under the paint will push it off the surface.
Not scraping thoroughly enough. Painting over loose paint just means the new paint peels off along with the old.
Ignoring caulk failures. Gaps let water in behind the paint film, and no paint can hold up to that.
Painting in poor weather conditions. Too cold, too hot, too humid, or too much direct sun can all prevent proper curing.

How Long Should a Good Paint Job Last on Wood Siding in WNY?

With proper prep and quality materials, you should get 7 to 10 years out of an exterior paint job on wood siding in our climate. Some homes in sheltered locations or with ideal sun exposure may get even longer. Homes on hilltops exposed to wind and weather, or those with persistent moisture issues, may see shorter lifespans.

The biggest variable isn't the paint. It's the prep. A premium paint over poor prep will fail in 2 to 3 years. A good mid-range paint over excellent prep can easily last a decade. That's why professional painters spend far more time prepping than actually painting.

Whether you own a home in Victor, Brighton, or anywhere else in the region, the same principles apply. Our climate demands that extra attention to detail during prep.

Should You DIY or Hire a Pro?

If your home is one story, the siding is in reasonable shape, and you have the time and patience, prepping and painting wood siding is a manageable DIY project. The key is not rushing the prep steps.

That said, there are situations where hiring a professional makes a lot of sense:

Multi-story homes that require ladders or scaffolding
Homes with lead paint that need safe removal protocols
Extensive rot or damage requiring carpentry repairs
Large homes where the project would take you multiple weekends (increasing the risk of weather-related problems between sessions)
When you simply want the job done right the first time without the learning curve

Professional exterior painting crews handle prep and paint as part of a single, efficient process. If you're looking at exterior painting services in the Buffalo area or need help with a home in Penfield, Henrietta, or Fairport, it pays to work with a crew that understands what WNY weather does to wood siding.

Get Your Wood Siding Painted the Right Way

If reading through all these steps makes you think, "I'd rather have someone else handle this," you're not alone. Prep work is the least glamorous part of painting, but it's the most important part. At MLZ Painting, we don't cut corners on prep because we know that's what makes the difference between a paint job that looks great for a couple of years and one that holds up for a decade.

We work with homeowners throughout Rochester, Buffalo, and the surrounding Western New York communities, including Lima and Geneseo. If your wood siding is due for a fresh coat, give us a call at (585) 362-2190 for a free estimate. We'll take a look at the condition of your siding, talk through what prep work is needed, and give you an honest quote for the job.

Why Prep Work Matters More Than the Paint Itself