Stucco & EIFS Cleaning
Porous, brittle at the surface, and in a climate that never gives a wall much chance to dry. Of everything we clean, this is the one where pressure does the most damage fastest.
A Surface That Absorbs Water, in a Place That Supplies Plenty
Stucco behaves almost opposite to vinyl. Where vinyl sheds water off a smooth face, stucco takes it in. The surface is porous by nature, which is fine in a dry climate and much less fine in one with eight wet months.
Add the second property and the problem compounds: stucco is brittle at the surface. Pressure does not simply clean it, it pits the texture, erodes the finish coat and will take out a weak or previously patched area completely. What you are left with is a wall that looks worse than when you started and now absorbs more than it did.
EIFS, the synthetic version built over foam board, is softer again and considerably less tolerant of water getting behind it. If there is any doubt about which system a house has, the right move is to treat it as the more delicate of the two until it is established, which is what we do.
Stucco gets the gentlest settings we use, which means soft washing throughout. Two things turn up on it repeatedly: algae and mildew held in the porous texture, and efflorescence carried out of the wall by moisture, which needs its own treatment rather than scrubbing.
How We Clean Stucco
Minimal pressure, maximum care around cracks and openings, and a clear eye on whether what you are looking at is dirt or a moisture problem.
Identify the System and Its Condition
Traditional stucco or EIFS, and where the cracking, patching and previous repairs are. This decides the approach and, occasionally, whether we recommend a stucco contractor before a cleaner.
Pre-Wet the Surroundings
Plantings and beds below are wetted so that any carryover is diluted on contact rather than absorbed.
Apply Solution at Minimal Pressure
A cleaning solution suited to masonry coatings, applied at the lowest effective pressure. On stucco the chemistry does all the work and the water is purely a carrier.
Keep Water Away From Cracks and Openings
Angles and distances are chosen so nothing is driven into hairline cracking, around window and door openings or up under trim and drip edges.
Rinse Gently and Report Back
The elevation is rinsed at the same low pressure, and you are told what we found. Cracking that needs attention, or staining that looks like moisture moving through the wall, is worth knowing about.
What We Address on Stucco
Stucco collects a distinctive set of problems, and some of them are not really cleaning problems.
Mildew & Algae
The green-grey cast on shaded and north-facing elevations, which the porous texture holds onto firmly.
Runoff Staining
Dark streaking below sills, drip edges and gutter joints where dirty water concentrates on the same path.
Efflorescence
White mineral bloom carried out of the material by moisture, which needs its own treatment rather than scrubbing.
Sheltered Areas
Soffits, recesses and under overhangs, where nothing weathers off naturally and growth accumulates quietly.
Patched & Repaired Sections
Often weaker than the surrounding wall and the first thing to fail under pressure, which is why we identify them first.
Moisture Symptoms
Staining that returns quickly after cleaning usually means water is moving through the wall. We flag it rather than rewashing it annually.
Frequently Asked Questions
Why is stucco the worst surface to pressure wash?
Two reasons that compound each other. Stucco is porous, so it absorbs water rather than shedding it, and it is brittle at the surface, so pressure pits and erodes the texture and will blow out a weak patch entirely. Combine those and high pressure does not just mark the finish, it pushes water into a wall assembly that has limited ability to dry, which is a far more expensive problem than a dirty wall.
What is the difference between traditional stucco and EIFS?
Traditional stucco is a cement-based coating over lath, reasonably robust and able to breathe. EIFS, often called synthetic stucco, is a layered system over foam insulation board and is considerably softer and much less forgiving. It can be dented by impact and is notoriously sensitive to water getting behind it. If you are not sure which you have, we will work it out on site and treat it as the more delicate of the two until we know.
There are hairline cracks all over mine. Does that matter for washing?
Yes, a great deal. Hairline cracking is common and often not structurally urgent, but every crack is a path for water into the wall. That is precisely why pressure is off the table here: forcing water at a cracked porous surface sends it exactly where it should not go. We clean at low pressure and we will point out any cracking that looks like it needs a stucco contractor rather than a cleaner.
Will washing get rid of the dark staining under the windows?
Usually it improves substantially. That staining is typically dirty runoff concentrating down the same path from a sill or a drip edge, often combined with mildew, and both respond to chemistry and dwell time. If the staining turns out to be a moisture problem moving through the wall rather than running down the face of it, cleaning treats the symptom, and we will say so instead of quietly repeating the job every year.
Have a question we didn't answer? Call (425) 298-7041or submit a quote request — we respond within 24 hours.
Soft Washing Across Seattle & the Eastside
Stucco is a minority finish here compared with the Southwest, but it clusters. Larger custom homes across Medina, Mercer Island, Bellevue and Sammamish account for much of the traditional stucco in our service area, and some of the townhome and condo development around Redmond, Issaquah and Lynnwood brought EIFS with it. In this climate both want cleaning on the gentle end and an eye on how the wall is handling water.
Pick your city for what we usually find locally.
Don't see your city? We work across the greater Seattle area, roughly an hour out from Kenmore. See the full service area, or call (425) 298-7041 and we'll tell you straight away whether you're in range.
Related Pages
Stucco sits alongside the other siding types we handle differently:
Stucco Needs the Gentlest Approach We Have
If a contractor quotes you a PSI for stucco, keep calling. Free assessment across Seattle, Bellevue, Kirkland, Redmond, Sammamish, Medina, Mercer Island, Issaquah and the wider Eastside.
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