Getting ready to paint your house outside? Great! But before you open that paint can, you need to do some prep work. Think of it like baking a cake—you can’t just throw everything together and hope it works. You need to follow the steps to get it right.
When you prep the house for painting the exterior the right way, your paint job can last 7 to 10 years. Skip the prep? You might see peeling and fading in just 2 or 3 years. That’s why prep work matters so much.
In this guide, you’ll learn all the steps to prep a house for exterior painting. We’ll keep it simple and easy to understand. By the end, you’ll know how to get your home ready for a fresh coat of paint that looks amazing and lasts for years.
Why Prep Work Matters So Much?
Here’s the truth: most painting problems don’t come from bad paint. They come from bad prep work.
When you rush through prep or skip steps, paint won’t stick right. You’ll see bubbles, cracks, and peeling. The paint might look good for a few months. But then problems start showing up.
Good exterior house painting prep helps your paint:
- Stick better to your walls
- Last much longer (up to 15 years with quality paint)
- Look smooth and even
- Stand up to rain, sun, and wind
Studies show that exterior paint typically lasts 5 to 10 years, but this depends heavily on how well you prepare the surface. Think of it this way—every hour you spend on prep saves you money and time later.
When to Start Your Project?
Timing matters a lot when you paint outside. You can’t just pick any day and start.
Check the Weather:
Paint in temperatures between 50°F and 80°F. Too cold? Water gets trapped under your paint and causes bubbles. Too hot? Paint dries too fast on top but stays wet underneath.
Also watch for:
- Rain in the forecast (wait at least 24 hours after rain)
- High humidity (makes paint dry slowly)
- Direct sunlight (can cause blistering)
Fall and spring are usually the best times. Summer works too, but paint early in the morning or late afternoon to avoid the hot sun.
Plan Enough Time:
Don’t rush this job. A full prep house exterior for a painting project can take several days or even weeks. Break it into smaller tasks:
- Day 1: Clean the house
- Day 2-3: Scrape and sand
- Day 4: Fix damage and fill holes
- Day 5: Prime bare spots
- Day 6+: Paint
Gather Your Tools and Supplies
Before you start, get everything ready. Running to the store mid-project wastes time and breaks your focus.
Cleaning Tools:
- Pressure washer (you can rent one)
- Garden hose
- Bleach or TSP cleaner
- Scrub brush
- Buckets
Scraping and Sanding:
- Paint scraper (tungsten-carbide blade lasts longer)
- Wire brush
- 80-grit sandpaper
- Random orbital sander
- Dust mask or respirator
Repair Items:
- Exterior wood filler
- Caulk (urethane acrylic works best)
- Caulking gun
- Putty knife
Painting Prep:
- Primer (exterior grade)
- Drop cloths
- Painter’s tape
- Ladder (follow the 4-to-1 safety rule)
- Safety glasses and gloves
Don’t buy cheap tools. Good brushes and scrapers make the job easier and give better results.
Step 1: Clear the Area
Walk around your house first. Look at everything.
Move or cover:
- Outdoor furniture
- Plants in pots
- Grills and toys
- Garden decorations
Trim back bushes and tree branches that touch your house. You need at least 2 feet of clear space to work safely.
Cover plants you can’t move with light drop cloths. Don’t use plastic—it gets too hot underneath and can kill plants.
Turn off air conditioning units and cover them with plastic and tape. Do the same for outdoor lights if you can’t remove them.
Step 2: Clean Everything Thoroughly
This step is super important. Paint won’t stick to dirt, mold, or mildew.
Pressure Washing:
A pressure washer is your best friend here. Allow at least 24–48 hours for the house to dry before painting after washing.
Tips for pressure washing:
- Stand back at least 5 feet from the wall
- Use green or white spray nozzles (softer spray)
- Work from top to bottom
- Don’t get too close (can damage wood)
For the cleaning solution, mix 1 cup of bleach with 5 gallons of water. This kills mold and mildew.
If your house has soft wood like cedar or redwood, don’t use high pressure. Hand scrub with detergent and water instead.
Check for Mold and Mildew:
Look for black, green, or brown fuzzy stains. Not sure if it’s dirt or mold? Put bleach on it. If the stain disappears, it was mold.
Clean all mold spots with bleach solution or a mold cleaner. This protects your health and helps paint last longer.
Step 3: Scrape Off Loose Paint
Now comes the hard work. You need to remove paint that’s peeling or cracking.
Walk around your house with a scraper. Look closely at every section. Push on the paint with your scraper. If it comes off easily, it needs to go.
You don’t need to scrape the whole house—just areas where paint is loose. Trying to remove all the paint takes forever and usually isn’t needed.
Important Safety Note:If your house was built before 1978, it might have lead paint. Use proper safety gear and follow EPA guidelinesfor lead paint removal.
How to Scrape?
- Hold your scraper at a low angle
- Push firmly but carefully
- Work with the wood grain
- Don’t gouge the wood
Use a wire brush for tight spots and corners. For really stubborn areas, a power sander with a paint-stripping pad works well.
The goal is to remove loose, flaky paint. Don’t worry about paint that’s stuck tight.
Step 4: Sand the Surface
After scraping, you need to sand. This does two things:
- Smooths out rough edges where old paint meets bare wood
- Roughs up glossy old paint so new paint sticks better
Use 80-grit sandpaper to feather the edge around scraped areas. “Feathering” means making a smooth transition. When you run your hand over it, you shouldn’t feel a bump.
Sand all bare wood spots too. This removes splinters and creates a good surface for primer.
For areas people will see up close (like by the front door), take extra time. Use finer sandpaper (120-grit) after the rough sanding for a super smooth finish.
After sanding, brush or blow off all the dust. Paint won’t stick to dusty surfaces.
Step 5: Fix Damage and Fill Holes
Look closely at your walls. Find:
- Cracks in the siding
- Holes from nails or screws
- Rotted wood
- Gaps between boards
Fix Rotted Wood:
Wood that feels soft or spongy has rot. You can’t just paint over it.
Use a wire brush to scrape away all the rotten parts. Dig until you reach solid wood. Fill the area with exterior wood filler or two-part epoxy. Let it dry completely, then sand smooth.
Big rotten areas might need new wood. This is important for protecting your home.
Fill Holes and Cracks:
Use exterior-grade wood filler for small holes. Push it in firmly with a putty knife. Smooth it flat with the surface. Let it dry, then sand.
For larger cracks, you might need to apply filler in layers. Let each layer dry before adding more.
Step 6: Caulk the Gaps
Caulking seals gaps and keeps water out. This step protects your home and makes the paint look better.
Where to caulk:
- Where siding meets trim
- Around windows and doors
- Between boards (if gaps are less than ¼ inch)
- Any other small gaps
Use urethane acrylic caulk. It costs more but lasts much longer and handles temperature changes better than cheap caulk.
How to Apply Caulk:
- Cut the tip at a 45-degree angle
- Hold the gun at an angle
- Apply steady pressure
- Smooth with your finger (wet it first)
Don’t caulk gaps bigger than ¼ inch. These need backer rod first, or they might need other fixes.
Step 7: Prime Bare Spots
Any spot where you scraped down to bare wood needs primer. Primer creates a smooth surface for painting and helps the paint last longer.
Use exterior-grade primer that matches your paint type. If you’re using latex paint over old oil paint, primer is extra important.
Pro Tip:Ask the paint store to tint your primer a color close to your final paint color. This helps you see where you’ve primed and might mean you need fewer coats of paint.
Let primer dry completely before painting. Check the can for drying times—usually 24 hours.
While primer dries, do your caulking. This saves time and keeps you moving forward.
Step 8: Do a Final Check
Before you start painting, walk around one more time.
Check for:
- Missed spots that need scraping
- Areas you forgot to fill
- Caulk that needs smoothing
- Primer that’s still wet
- Tools or supplies left in the way
Fix any problems now. Once you start painting, it’s too late.
Make sure all surfaces are completely dry. Touch them with your hand. If they feel even slightly damp, wait another day.
Common Mistakes to Avoid
Even with the best plans, mistakes happen. Here are the big ones to watch for:
Skipping the CleaningPaint can’t stick to dirt. Always wash first, even if your house looks clean.
Rushing the Drying Time: Water trapped under paint causes all kinds of problems. Be patient. Let everything dry fully.
Using Cheap Materials: Cheap scrapers break. Cheap caulk cracks. A cheap primer doesn’t protect. Spend a bit more on quality supplies.
Painting in Bad Weather: Check the forecast. You need at least 24 hours of good weather after you paint.
Not Wearing Safety Gear: Protect your eyes, lungs, and skin. Dust and paint chips can be dangerous, especially if you have lead paint.
Forgetting to PrimeBare wood without primer soaks up paint like a sponge. You’ll use more paint and get worse results.
Working with UDA Services
Sometimes, prep work feels overwhelming. That’s normal! It’s hard work that takes time and attention to detail.
If you need help with your painting project, our team at UDA Services can handle everything. We know how to prep the house exterior for painting the right way. We’ve done it hundreds of times.
We also offer other services like deck and patioconstruction and home additions. Check out our galleryto see examples of our work.
Final Thoughts
Getting your exterior house painting prep done right takes time and effort. But it’s worth it. When you clean, scrape, sand, fix, caulk, and prime properly, your paint job looks amazing and lasts for years.
Remember the main steps:
- Clear and protect the area
- Clean everything with pressure washing
- Scrape off loose paint
- Sand smooth transitions
- Fix damage and fill holes
- Caulk all gaps
- Prime bare wood
Take your time with each step. Don’t rush. The prep work before painting the exterior house is just as important as the painting itself—maybe even more important.
Ready to give your home a fresh new look? Whether you tackle this project yourself or work with professionals, good prep work is the secret to a paint job you’ll love for years to come.
For more help with your outdoor projects, contact usat UDA Services. We’re here to make your home look its best!