Why Pressure Washing Is Not Surface Preparation
Pressure washing is useful.
But it is not surface preparation.
This is one of the biggest misunderstandings in cleaning, painting, and restoration work. Many people think that if a surface looks clean after pressure washing, it’s ready for paint or coating.
That’s usually not true.
What Pressure Washing Is Good At
Pressure washing uses water to remove:
dirt
mud
loose debris
mildew
surface grime
It’s great for cleaning sidewalks, buildings, and exterior surfaces that just need to look better.
Pressure washing improves appearance, not bonding.
What Surface Preparation Actually Means
Surface preparation is about getting a surface ready to hold onto a coating.
That means:
removing rust
removing failing paint
creating surface texture
eliminating contaminants that cause adhesion failure
Surface prep focuses on performance, not looks.
The Big Difference: Texture
Paint and coatings need something to grab onto.
That grip comes from surface texture, also called surface profile.
Pressure washing:
does not create texture
does not roughen the surface
does not open up the material
Media blasting does.
Without texture, coatings rely only on chemical stick, which fails much faster.
Why Pressure Washing Fails on Rust
Pressure washing cannot:
remove bonded rust
clean inside pits
stop corrosion from continuing
Rust that looks “clean” after pressure washing is often still active below the surface. When paint goes on top, rust keeps working underneath.
That’s why paint often bubbles or peels months later.
Why Pressure Washing Fails on Old Paint
Old paint fails because it loses adhesion.
Pressure washing might knock off loose paint, but it:
leaves weak edges behind
does not remove tightly bonded failing layers
does not create a uniform surface
New paint sticks only as well as the old paint underneath it.
Where Pressure Washing Fits in the Process
Pressure washing has a place.
It’s often used:
before blasting to remove heavy dirt
after blasting to rinse surfaces
for maintenance cleaning when no coating is planned
It’s a support tool, not a prep method.
When Media Blasting Is Required
Media blasting is needed when:
rust is present
paint is failing
coatings need to last
surface texture matters
Blasting removes material, not just dirt. It prepares the surface so coatings can bond mechanically and last longer.
Common Mistakes People Make
Some common problems include:
painting right after pressure washing
skipping blasting to save money
assuming clean means prepared
blaming paint when prep failed
Most coating failures trace back to poor surface preparation.
Frequently Asked Questions
Q: Can I paint after pressure washing?
A: You can, but it usually won’t last as long.
Q: Is pressure washing cheaper than blasting?
A: Yes, but failed coatings cost more to fix later.
Q: Does pressure washing remove all contaminants?
A: No. Oils, rust, and embedded coatings remain.
Q: Can pressure washing replace blasting?
A: No. They serve different purposes.
Final Thought
Pressure washing makes surfaces look clean.
Surface preparation makes coatings last.
If the goal is durability, blasting matters.
If the goal is appearance only, pressure washing may be enough.
Knowing the difference saves time, money, and frustration.
Next up: Why Paint Fails (Even When Applied Correctly).
