Is pressure washing safe on limestone?

No — limestone is a soft, porous stone. High-pressure water forces its way into the pores and can etch the surface, strip the natural patina, and accelerate freeze-thaw damage over a Missouri winter. Soft washing (low pressure, a cleaning solution that does the work instead of PSI) is the correct method for limestone facades, window surrounds, and hardscaping.

Is pressure washing safe on brick?

Modern fired brick handles moderate pressure well, which is why we pressure wash brick concrete flatwork and some brick facades at calibrated PSI. Older or soft-fired brick and the mortar joints between bricks are more vulnerable — high pressure can blow out mortar and force water behind the brick veneer. We soft wash brick facades with visible mortar wear or on pre-1980s St. Louis homes.

Is pressure washing safe on vinyl siding?

Vinyl siding tolerates pressure washing better than stone or older masonry, but high PSI or the wrong nozzle angle can force water up under the panels and behind the seams, leading to mold growth you cannot see. We use lower pressure and a downward spray angle on vinyl, and soft wash whenever algae or mildew staining (not just dirt) is the problem.

Is pressure washing safe on slate?

Slate used for roofing, walkways, or patios is dense and generally pressure-washing tolerant, but the mineral coating that gives slate its color can be stripped by excessive PSI or a tight-angle nozzle held too close. We pressure wash slate flatwork at reduced PSI with a wide fan tip, and soft wash slate roofing entirely — a pressure washer on a roof is also a fall-risk and warranty concern most manufacturers void outright.

How much does soft washing cost in St. Louis?

Soft washing is $0.25 per square foot, flat-rate. A typical West County estate facade runs $600–$1,200 depending on total square footage. Call (314) 888-5325 for a square-footage estimate.

How much does pressure washing cost in St. Louis?

Pressure washing concrete flatwork — driveways, patios, walkways — is $0.20 per square foot, flat-rate. A full exterior package combining concrete flatwork and siding soft wash typically runs $600–$1,200. Call (314) 888-5325 for a square-footage estimate.

Soft Wash vs. Pressure Wash St. Louis: Which Is Safe for Your Home

Both methods clean an exterior — they do it in opposite ways. Pressure washing removes buildup with force (PSI). Soft washing removes buildup with a cleaning solution and low pressure. Using the wrong one on the wrong surface is how limestone gets etched and vinyl siding gets water damage nobody sees until the mold shows up. The right call depends on the material, not the stain.

Which Method for Which Material

West County homes mix limestone, brick, vinyl, and slate on the same property — sometimes on the same facade. We assess material-by-material before quoting, not one method for the whole house.

Material	Safe Method	Why
Limestone	Soft Wash	Soft, porous stone. High pressure etches the surface and drives water into pores, accelerating freeze-thaw damage over a Missouri winter. Low-pressure soft washing with the right cleaning solution is the only method we use on limestone facades and hardscaping.
Brick	Depends on age	Modern fired brick and concrete flatwork tolerate calibrated pressure washing well. Older or soft-fired brick, and the mortar joints on any brick, are more vulnerable — we soft wash brick facades on pre-1980s homes or wherever mortar shows wear.
Vinyl Siding	Pressure OK, care needed	Vinyl handles moderate pressure, but the wrong angle can force water behind panel seams and cause hidden mold growth. We use lower pressure with a downward spray angle, and soft wash entirely when algae or mildew — not just dirt — is the problem.
Slate	Soft Wash (roofing) / Low-PSI (flatwork)	Dense and generally pressure-tolerant for walkways and patios at reduced PSI with a wide fan tip. Slate roofing is soft-wash only — a pressure washer on a roof strips the mineral coating, is a fall risk, and voids most manufacturer warranties outright.

Flat-Rate Pricing — Per Square Foot, No Surprises

Both methods are priced flat-rate per square foot. Neither is inherently more expensive — the total depends on how much of your home needs each treatment.

Soft Washing

$0.25/sq ft

Limestone, brick facades with mortar wear, cedar shake, algae and mildew removal, slate roofing.

Pressure Washing

$0.20/sq ft

Concrete flatwork — driveways, patios, walkways — modern brick, and calibrated-PSI slate hardscaping.

Full exterior packages combining both methods on a larger West County property typically run $600–$1,200 depending on total square footage. Call for a walk-through estimate.

Not Sure Which Method Your Home Needs?

We assess every surface before we quote — limestone gets soft washed, concrete gets pressure washed, and mixed-material facades get both where each is appropriate. Flat-rate quotes, $2M insured on every visit.

Get a Free Exterior Estimate Call (314) 888-5325