Stucco cleaning: identify the finish before choosing a wash

Start by identifying the wall

A textured wall does not tell you whether it is cement stucco, EIFS or a coated system. Look for building records, a manufacturer name or prior repair documentation. Photograph cracks, soft spots, missing sealant and discoloration before a contractor wets the surface. Those defects may call for repair rather than cleaning. If water gets behind a failing finish, a bright appearance after washing is a poor trade for hidden damage.

Let the finish instructions set the method

Manufacturers provide more useful limits than a generic promise of a “soft wash.” Sika’s Parex bulletin for its EIFS and stucco finishes says not to exceed 500 psi, to keep a nozzle at least two feet from the wall, and to use a wide fan tip. Dryvit’s guidance likewise emphasizes that a compatible cleaner, rather than spray force, does the cleaning. Those figures apply to their systems and are not a universal setting for unknown walls. Ask the contractor which manufacturer guidance applies to your house.

Request a test area and a rinse plan

• Have the contractor name the stain: ordinary soil, algae, efflorescence, rust, irrigation residue or a coating failure may require different responses.
• Ask for a small test patch in an inconspicuous area, then evaluate it after the wall dries. Wet color can hide uneven cleaning or damage.
• Ask what will be masked or pre-wetted, including windows, doors, plants, electrical fixtures and nearby painted trim.
• Confirm the cleaner’s dwell time and how the wall will be rinsed before the solution dries. Direct sun and heat can change that timing.

A low-pressure application still needs a clear runoff route. San Antonio’s stormwater guidance for businesses says washwater and cleaning chemicals should not flow into a storm drain. That is a concrete question for a provider working near a driveway or street inlet, especially when detergent is involved. Ask how water will be contained or directed according to the site and local rules.

Read the dry test, not the wet wall

A wet patch can make adjacent areas look darker or temporarily hide a color difference. Look again after the tested section dries. Did the surface soil change? Is an older repair now more visible? Does the coating appear intact? Ask the wall specialist what the test actually demonstrates before extending it across the elevation. A remaining mark is not, by itself, a reason to increase pressure or try a stronger mixture. Cleaning should answer a defined surface problem; it cannot make an unknown finish, a failing patch or a moisture defect sound.

When to pause the job

Do not wash over a crack or loose finish as if cleaning will repair it. If the finish peels in a test patch, water appears behind the surface, or the manufacturer instructions are unavailable for a vulnerable system, stop and ask a qualified stucco or EIFS specialist to assess it. This article is a selection guide, not an offer that Texas Window Washing performs wall washing.

One wall can contain several separate problems

Imagine a patio wall with a dusty open area, a dark streak beneath a window, and a patch from an earlier repair. This is a planning example, not a completed job. Treating all three as ordinary dirt would skip important questions. The dusty area may be suitable for a manufacturer-compatible cleaning test. The streak needs a discussion of its source, particularly if the window or sealant has a known leak. The repaired patch may simply differ from the surrounding finish. Ask a qualified wall specialist to distinguish these possibilities. Approving a wash for one section does not establish that the same process will improve every mark on the wall.

Leave the cleaner recipe to the identified system

A product marketed for “stucco” is not enough information when the wall system is unknown. Give the specialist any finish label, repainting record or repair invoice you have. If none exists, say so. Ask which instructions support the proposed treatment and whether the uncertainty can be resolved before the wall is wetted. For a known system, the useful limits include compatible cleaner, application, rinse and any temperature or exposure guidance in that system’s documentation. This guide does not supply a universal chemical mixture or offer wall washing as a Texas Window Washing service.