The short answer: low pressure, material by material
Mid-century modern homes are cleaned best with a soft wash approach: a mild cleaning solution, time to dwell, and a low-pressure rinse. High pressure has a narrow role, mostly on flat concrete and terrazzo-free paving. Everything else, from floor-to-ceiling glass to exposed beams, gets gentler treatment.
The reason is that these houses put many different materials within a few feet of each other. A wand setting that is fine for a concrete carport can raise the grain on a redwood fascia or push water past an old window gasket. So the job is planned around the most fragile surface in each zone, not the toughest one.
Large glass walls and clerestory windows
Glass is not hard to clean, but big panes in aluminum or wood frames have seals and weep holes that do not like direct spray. Aim the rinse down the glass at a shallow angle, never straight into the joint where glass meets frame. On older homes, check for dried or cracked glazing putty first. Water forced behind it can end up inside.
Hard water spotting is the common complaint in LA. A final rinse with plain tap water can leave fresh spots once it dries in the sun, so glass is best washed in shade or early in the day and squeegeed or dried by hand. Mineral spots that have sat for years may only lighten with washing and can need a dedicated glass treatment.
Exposed beams, tongue-and-groove and wood siding
Open eaves and beams that run from inside to outside are a signature of the style. They collect cobwebs, dust and gray weathering. Wood should be washed with a wood-safe cleaner, soft brushes where needed, and a low-pressure rinse that keeps the stream moving with the grain. Concentrated pressure leaves fuzzy, splintered lines that show once the wood dries.
Overhead wood also drips. Washing top-down means the beams and soffits come first, then the walls and glass below get a final rinse to carry away anything that ran down. If the wood finish is already peeling or the wood is soft, cleaning will expose that rather than fix it. That is a refinishing or repair conversation. Our wood siding guide goes deeper on stains and finishes.
Breeze block, stucco and painted masonry
Decorative breeze block walls trap dirt and spider webs in every opening, and the inside edges often grow a thin film of algae on shaded sides. They clean well with a soft wash solution, a short dwell, and a rinse from several angles so each opening gets flushed rather than blasted.
Many of these blocks are painted. Paint that is already chalking or flaking will come off in spots during any kind of wash, so test a small area first. The same goes for smooth stucco walls, which should be soft washed rather than pressure washed to protect the finish.
Terrazzo, aggregate and original concrete
Original terrazzo entries and patios are polished stone chips set in cement. They respond to a neutral or mild cleaner and a gentle rinse. Acidic cleaners can etch the marble chips and dull the surface, and high pressure can open small pits. Old terrazzo that has lost its shine needs honing and polishing by a specialist, not more washing.
Plain concrete driveways, carports and walkways are where higher pressure belongs. A rotary surface cleaner lifts dirt evenly without the striping a single nozzle leaves. Exposed aggregate paths, common on these homes, need lower pressure so loose stones are not knocked out.
Mistakes that show on a mid-century house
The big ones are spraying up under overhangs into attic vents, aiming at window seals, using one pressure for everything, and letting cleaning solution dry on glass in the Valley afternoon sun. Each leaves a visible mark or a hidden leak.
Another is skipping plant protection. These homes often have tight, architectural landscaping right against the glass. Pre-wetting plants, covering delicate ones, and rinsing them again after keeps solution from sitting on leaves. Under Los Angeles Municipal Code section 64.70.02, wash water from paved areas cannot be sent untreated into the storm drain, so runoff from the driveway needs to be managed too.
What it costs and how we approach it
As of October 2026, house washing on our calculator is $0.35 per square foot of exterior wall, driveway cleaning is $0.50 per square foot, and patio cleaning is $0.65 per square foot, with a $195 minimum per visit. Booking two services together takes 5% off, and three or more takes 10%.
At Say Wash It we treat a mid-century house as a series of small jobs with different rules. The flat price is confirmed before work begins, and we walk the property with you at the end so you can see the glass, wood and concrete up close. The instant quote on this page is the fastest way to get a starting number.
Key points
The short answer: low pressure, material by material
Mid-century modern homes are cleaned best with a soft wash approach: a mild cleaning solution, time to dwell, and a low-pressure rinse. High pressure has a narrow role, mostly on flat concrete and terrazzo-free paving. Everything else, from floor-to-ceiling glass to exposed beams, gets gentler treatment.
Terrazzo, aggregate and original concrete
Original terrazzo entries and patios are polished stone chips set in cement. They respond to a neutral or mild cleaner and a gentle rinse. Acidic cleaners can etch the marble chips and dull the surface, and high pressure can open small pits. Old terrazzo that has lost its shine needs honing and polishing by a specialist, not more washing.