How To Prep A House For Exterior Painting

So, you’ve taken a look and decided that it’s time to give your home a new coat of paint. Or, maybe you want to go with something totally different. However, for many, the thought of tackling a DIY project as large as painting a house exterior can be pretty overwhelming.

While we can’t promise you it will be a walk in the park, the project is much more manageable when you’ve taken the right preparations. and below, we’ll show you just what to do to set yourself up for success.

How To Prep A House For Exterior Painting

Before You Get Started

Talk about the tools needed and safety best practices.

  • Buckets (for cleanup)
  • Garden hose
  • Bleach and/or cleaning solution
  • Rags
  • Safety Goggles
  • N100 Respirator with HEPA filter cartridges or dusk mask (depending on the presence of lead paint)
  • Protective suit (optional if working with lead paint)
  • Spray shield
  • Wire brush
  • Primer
  • Ladder
  • Exterior paint with stir sticks
  • Pressure washer
  • Trim paint
  • Painter’s tape
  • Paint brushes, roller, and/or sprayer
  • Drop cloths
  • Wood filler
  • Paint scraper
  • Sander
  • Spackle knife
  • Sanding Block (medium grit)
  • Sander
  • Caulk gun
  • Exterior caulk
  • Plastic bags or wrap
  • Trash bags

How To Prep A House For Exterior Painting: Getting Started

Before getting started, be sure to remove all items near your home, such as grills, furniture, trash cans, and store them away from your home. It’s also a good idea to tape any outlet boxes and other fixtures using painter’s tape and drop cloths. Also, cover sensitive objects like fountains and flowers to prevent damage or contamination.

Here is a simple, step-by-guide to preparing the exterior of your home for painting.

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Step 1: Pressure wash to clean your home’s exterior

If there’s one thing that’s absolutely essential for ensuring a successful paint job, it has a clean surface. This is where a powerful pressure washer comes in. Using this machine with the right detergent is by far the most effective way to thoroughly clean your home’s exterior siding.

However, you’ll need to use caution when selecting the right nozzle. If you use a stream that’s too concentrated, it could damage wood, get water underneath any lapped siding, and even break windows! You should also direct the water in the same direction rain hits your home. Keep in mind your siding is only designed to protect your home from water damage coming from a downward trajectory.

On those surfaces that are not experiencing excessive flaking or peeling, you can use a garden hose and scrub brush to give it a good cleaning.

An excellent cleaning agent that’s safe to use is Trisodium phosphate (TSP). And a detergent that contains a mildewcide will do wonders for removing and preventing mildew. Or, you can just mix a quart of regular bleach in three quarts of water. For any cleaning product you choose to employ, please make sure you read all instructions carefully. For more details, you can watch this video showing how to pressure wash a home.

Step 2: Scrape off all loose paint and test for Lead

If your home was built pre-1978, then it’s possible that it’s coated using lead-based paint. This type of paint is harmful to your family, neighbors, and pets, which is why the EPA banned it for residences.

  • Purchase a lead testing kit at your local hardware store or online, or take some paint chip samples over to a testing lab. If the test comes back positive, you will need to take the following precautions:
  • Utilize a HEPA vacuum
  • Ensure you’re wearing an N100 or another professional-grade respirator with fresh HEPA cartridges along with a microporous protective suit.
  • Dampen the existing exterior paint using a spray bottle to help minimize the toxic dust particles.
  • Put down a few plastic drop clothes to collect scrapings.
  • Dispose of hazardous waste using sealed trash bags.

And if your paint doesn’t contain led, then a dusk mask sh0uld be sufficient, although I personally recommend a respirator.

Now it’s time to scrape.

Take a scrapping tool or wire brush to remove flaking paint not cleaned during the pressure washing process or that the pressure washer couldn’t reach. If the old paint is intact, then scraping down to bare wood is not necessary. You can always paint over it after sanding.

Step 3: Sanding

Sanding is a very important step to ensure a strong mechanical bond between each coat of paint. Ensure the paint isn’t bumpy or lumpy before using 80-grit sandpaper to smooth the surface.

You can speed up this process by using a power sander or grinder. However, these tools can damage old layers. If you decide to scrape by hand, using a heating gun can soften old paint to make it easier to scrape off. To get rid of scratches sand, use 100-120-grit paper. If you have weathered wood, use medium-grit paper. And for doors and trim, use fine-grit.

Step 4: Patch holes, remove caulk, and repair/replace rotting wood.

Once you’ve finished sanding, replace any trim or siding that can’t be salvaged. If you have rotting wood, you can use epoxy to repair it or just replace it. For rotten spots and deep cracks, you’ll need a good two-step epoxy. But, you should avoid using auto-body fillers on your wood as they tend to cure too hard. While they can look good at first, the filler will eventually begin peeling away.

You’ll want to hold off on caulking cracks until you’ve primed since your primer will protect the wood when your caulk fails.

Before priming, remove the old caulk.

Step 5: Priming

Primers are specially formulated to penetrate wood provide a good seal along with a catchy surface that will allow topcoats to stick much better. These are used over bare wood, epoxy, sparkle, or surface with deteriorated and chalky paint. However, if the painting surface is sound and clean, you may consider skipping this step.

You can use Acrylic primers on nearly any surface, except for redwood and cedar. For those woods, you’ll need oil=based paint since it’ll need to lock in the reddish=bropwn extractives” in the wood that will leach out, leaving behind rust stains should you prime the wood using a water-based product.

Many might suggest tinting the primer as close to the color of the topcoat as possible, but this can also lead to missed spots (holidays). Instead, try tinting your primer using a different color. That way, if you see the color bleeding through, you’ll know just where to apply more paint.

And if you spray the primer using a power sprayer, you can use a manual brush technique called “back-brushing” to work the primer into every crevice and crack.

Another tip is using a metal primer on exposed nailheads. This will prevent any rust from bleeding through your paint.

Step 6: Caulk gaps and cracks

After the primer dries, fill in gaps around windows, doors, and trim using a caulk gun filled with exterior caulk.

Caulk any joints that are less than a quarter-inch wide in the trim and siding. The pros prefer using siliconized acrylics, as paint won’t stick. However, some also like the newer and more expensive urethane acrylics as they have greater longevity and flexibility.

One good reason not to buy cheap caulk is that if a joint fails, you’ll have to start back at square one. However, don’t expect any 35-year caulk to last the full 35 years. However, it will definitely last much longer than the cheaper 15-year-caulk.

Other Considerations

Here are some other factors to consider while preparing to paint your home’s exterior.


So many quality paint jobs have been ruined by bad weather conditions. Keep in mind your paint will need time and the right environment to dry properly. That’s why you want to plan your projects during a season or week when there’s relatively low humidity. While it’s no fun painting in the hot sun, such dry conditions can help your paint dry faster. And there are few things as soul-crushing as feeling raindrops just after you’ve applied your final coat of paint!

It would be best if you also kept in mind that many paints and caulks have a limited range of temperatures in which they work well. For instance, if it’s too cold or too hot, they may either cure slowly or perhaps not at all. Just be sure to read the labels, and you shouldn’t have any issues.

If you have to paint in humid conditions, make sure you check the previous coat carefully before you apply another. You also want to account for the sun. Areas of your home that receive very little to no direct sunshine will dry slower. And sections that with direct sunshine will develop a harder surface that can become dry to the touch even before they are completely cured.

Paint thinner

One very basic preparatory step that can save you lots of time and headaches is making sure you have a solution on hand to deal with spills. You’ll just need a few cleaning rags and water if using latex paint. But for enamel or oil-based paints, you’ll need either paint thinner or mineral spirits. We recommend using the kind made by the manufacturer of the paint you’re using for the best results.

Most labels on paint cans will tell you what they offer under the “Directions for Clean Up” section.

Another tip: The terms paint thinner and mineral spirits are sometimes used interchangeably. While they are very similar, mineral spirits are used more often for painting indoors because they produce lower fumes. Paint thinner is often less expensive but contains higher Volatile Organic Compounds (VOC).

Outdoor pets

If you have outdoor pets, you may want to consider taking them to another location like a neighbor’s home or day spa or bringing them indoors for a while. The last thing you want is for your furry loved ones to be moving around your work area, messing up your supplies and setup. And, of course, they can be affected by scraping, sanding, and falling debris. You especially want to relocate them if you discover the presence of lead paint.

Proper scaffold and sadder setup

Painting a home’s exterior is often a multi-story job, meaning you’ll likely need a ladder or possibly a scaffold. This can be a trickier proposition than when you’re working indoors because of the unevenness of the ground. It’s always a good idea to have another person with you holding the ladder when working on soft ground. You can also learn more about how to work with scaffolding in this guide safely.

Test Swatch

Before you dive head-first into painting mode, you should test by putting a swatch of paint on a surface. This step is only useful if you want to ensure that the paint you picked out will match the shade you have. This test isn’t necessary if you’re applying a different color or shade.

Costs: DIY Versus Hiring a Professional

For folks who want to take on the DIY project of painting their home’s exterior, the average cost will total about $750-$900 (possibly a bit more depending on the supplies you need).

You can look to spend between $20-$80 for every gallon of paint. And other materials such as an orbital sander and power washer can drive up the costs as well. Of course, there are devices you may be able to rent from a hardware store to cut down on costs.

On the other hand, to hire a contractor, you can expect to pay anywhere from $1750 to $4,500 or about $1 per foot if your home consists of stucco, brick, or vinyl.

But, if your home is pretty tall with multiple stories, it may be way safer to budget a professional painter with an experienced crew who knows how to use scaffolding, ladders, safety harnesses, and lifts.

Final Thoughts on How to Prep a House for Exterior Painting

As you can see, prepping a home for exterior painting requires a lot of work before you even begin painting. But every step is important in assuring that you have a quality finish that stands the test of time.

And once again, we can’t stress enough how important it is to consider safety before taking on this DIY project. If your home has more than two floors or the ground around it is very uneven, it might be worth considering a professional service.

Otherwise, if you follow our advice, you should be able to knock this project out over a weekend and stand proudly on Monday as your neighbors “ooh and aah” at your home’s spiffy new paint job.

Not interested in prepping your home? Let us do all the work for you! Schedule your free estimate today.