House washing that's gentle on your siding

What builds up on siding, and why

Siding collects two kinds of grime. The first is ordinary dirt: dust, pollen, cobwebs and exhaust. The second is organic growth: algae, mildew and mold that feed on that dirt and on the moisture that lingers on shaded walls.

The growth is the part that matters. It's what turns siding green or black, it's what comes back after a quick rinse, and it's the reason a simple hose-down or a pressure washer rarely fixes the problem for long.

Signs your house needs a wash

Walk around the outside of your home and look for:

• A green film on the north side or on walls shaded by trees and fences. That's algae.
• Black or gray spots under the eaves, around gutters and near downspouts. Usually mildew.
• A dull, gray cast over light-colored siding, even where you don't see spots.
• Dirty soffits and trim, spider webs and wasp nests in the corners.
• Streaks below windows and light fixtures, where water runs down the wall.
• A chalky residue that comes off on your hand, common on older siding.

Most homes show at least two of these after a couple of years without a wash, and the shaded sides always go first.

Algae, mildew or mold: what's on your siding?

People use these words interchangeably, but they look a little different, and knowing which one you have tells you a lot about your house.

• Algae is the green or blue-green film, most often on the north side and on walls that stay damp. It's the most common growth on siding in the Chicago suburbs.
• Mildew shows up as small black or gray spots, often under eaves, around gutters and on trim, where moisture collects and air doesn't move much.
• Mold is usually fuzzier and can be black, green or other colors. On the outside of a house, it tends to appear in the same damp, shaded spots as mildew.

The good news is that all three are organic growth, and all three respond to the same approach: a cleaning solution that kills them at the root, followed by a gentle rinse. If growth keeps returning quickly in one spot, it's usually a sign of a moisture source nearby, like a gutter overflowing or a sprinkler hitting the wall, and we'll point it out.

Our soft wash house washing process

1. Walk around and quote. We check the siding type, the level of growth, windows, lights and landscaping, then give you a clear price.
2. Protect first. Plants, shrubs and lawn are soaked with water, and outlets, fixtures and anything delicate are covered where needed.
3. Soft wash. A cleaning solution matched to your siding is applied at low pressure, from the bottom up, and given time to break down the growth.
4. Rinse. Everything is rinsed from the top down at low pressure, and plants are rinsed again.
5. Walkthrough. We walk around the home with you to make sure you're happy with the result.

Because the growth is killed rather than just knocked off, your siding stays cleaner for longer than it would after a pressure wash.

Should you power wash a house?

It's the most common way people ask for this service, and it makes sense: power washing is the method most people know. But for the house itself, high pressure causes more problems than it solves.

• It damages siding. Pressure can crack or warp vinyl, erode stucco, dent aluminum and strip paint.
• It pushes water where it shouldn't go. Siding is built to shed rain falling from above, not water blasted at it from below and at close range.
• It doesn't last. Pressure knocks off the visible stain but leaves the roots of algae and mildew behind, so the green comes back fast.

So when you ask us to power wash your house, we'll soft wash it: the same clean result, without the damage, and it stays clean longer. Power washing still has its place on the ground around your home, and we offer power washing for your driveway, walkways and patio in the same visit.

Vinyl siding cleaning

Vinyl is the most common siding we wash, and the one most often damaged by DIY pressure washing. High pressure can crack or warp panels, strip their finish and drive water behind them, where it can soak insulation and sheathing.

Soft washing avoids all of that. The cleaning solution does the work on the green algae and mildew, and the rinse uses about the pressure of a garden hose. Vinyl comes back to its original color without streaks or water trapped behind the panels.

Older vinyl can also develop a chalky film as the surface ages in the sun. We'll point it out if we see it, because it behaves differently from dirt and growth.

The most common DIY mistakes on vinyl:

• Spraying upward. Vinyl panels overlap like shingles, facing down. Spraying up from below drives water straight into the gaps and behind the siding.
• Getting too close. Even a small pressure washer can gouge or crack vinyl when the tip is held close to the surface.
• Scrubbing hard. Stiff brushes leave swirl marks and can dull the finish.
• Using the wrong cleaner. Strong household products used straight from the bottle can streak siding and burn plants below.

A soft wash avoids every one of these: the solution does the cleaning, and the rinse runs from the top down at low pressure.

Stucco, Dryvit and EIFS cleaning

Stucco and EIFS (exterior insulation and finish systems, often called Dryvit after one well-known brand) look similar but need to be handled carefully for different reasons.

• Traditional stucco is hard but porous. High pressure can erode the finish, open hairline cracks and push water into the wall.
• EIFS and Dryvit have a thin finish coat over foam insulation. High pressure can gouge the surface or force water behind it, and water behind EIFS is one of the most expensive problems a wall can have.

Both collect algae and mildew in their textured surface, especially on shaded sides. Soft washing lifts it out of the texture with a cleaning solution and a gentle rinse, with no force on the wall. Why low pressure matters for siding.

Washing is also a good moment to look closely at the wall. While we work, we watch for signs that water may be getting behind the finish: dark stains spreading below window corners, cracks around openings, soft or bulging spots and damaged sealant. If we see any, we'll show you, because those are worth having a stucco or EIFS specialist check before they grow. Cleaning won't cause them, and it won't fix them, but a clean wall makes them much easier to spot.

Aluminum siding cleaning

Many older homes in and around Arlington Heights still have aluminum siding. Over the years its painted finish oxidizes and turns chalky: rub your hand on it and it comes away white.

Aluminum needs a gentle approach. Heavy pressure or harsh scrubbing can dent the panels or wear through the paint. We soft wash aluminum to remove dirt and growth, and we'll tell you honestly how much of the chalking a wash can improve, since heavy oxidation is a finish issue rather than a cleaning one.

Planning to paint? Aluminum siding has to be clean and free of loose chalk before new paint will stick. A soft wash is a common first step before repainting, and it gives your painter a clean surface to start from.

Other siding we wash

• Fiber cement (such as Hardie board). Durable, but its painted finish can be scuffed by pressure. It soft washes very well, and manufacturers recommend low-pressure cleaning.
• Brick. Brick itself is tough, but older mortar joints can be eroded by high pressure. Soft washing removes the green and black growth that settles into the rough surface of brick on shaded walls.
• Wood and cedar. High pressure raises and splinters the grain. A soft wash cleans wood without damaging it, and it's the right first step before re-staining. See fence and deck cleaning.

Our siding cleaning services cover all of these, and if you're not sure what your siding is, send us a photo and we'll tell you.

Homes with more than one type of siding

Plenty of homes around Arlington Heights mix materials: a brick front with vinyl on the sides, stucco on one level and siding on another, or wood trim around aluminum. That's not a problem for a soft wash, but it does mean one method doesn't fit the whole house.

We plan the wash wall by wall. Each surface gets a solution strength and rinse suited to it, and transitions between materials, like the joint where brick meets siding, get extra care so water isn't pushed into the seam. You get one visit and one price, with every surface cleaned the right way.

When to schedule a house wash

• Spring, to clear winter grime and the first pollen.
• Fall, to remove a summer's worth of algae and mildew before it sits on the house all winter. Many homeowners prefer this one.
• Before selling, so the house looks its best in listing photos and showings.
• Before painting, since paint only holds on a clean surface.
• Before a big event at home, like a graduation party or family visit.

Soft washing needs temperatures above freezing, so in the Chicago suburbs the season runs roughly spring through late fall. For what to do on the day, see our FAQ.

Plant, pet and lawn safety

The most common question we hear is whether soft washing will hurt the garden. Here's how we protect it:

• Plants, shrubs and lawn are soaked with water before any solution goes on, so they don't absorb it.
• The solution is applied only where it's needed, at low pressure, with no overspray drifting across the yard.
• Everything planted near the house is rinsed again when the wash is done.
• We ask that pets stay inside during the wash and until surfaces are dry.

What's included in our house washing services

• Siding on every side of the home
• Soffits and fascia
• Outside faces of the gutters (full gutter brightening is available for heavy black streaks)
• Exterior window frames and trim
• Front door area, light fixtures and shutters

What does house washing cost?

Price depends on the size of the home, how many stories it has, the siding type and how much growth there is. We give you a clear price before anything is scheduled, with no surprises afterward. For a breakdown of what drives the cost, see our guide to house washing prices.