How Often Should You Power Wash Your House?

The house got washed once. Maybe two summers ago, maybe it came that way when you bought it. Now a green film is creeping across the shady side again, and you are wondering if this is going to be a yearly thing.

For most homes around here, it is. Here is how often a house really needs it, what makes the green come back faster, and how to make a wash last.

The Short Version

• How often? About once a year for most Delaware homes. CertainTeed, which makes vinyl siding, recommends the same.
• Why does the green keep coming back? It is living growth, and in Delaware's humidity the shady north side of a house can go from clean to green in a single summer.
• Should you power wash it? No. High pressure can blow water behind siding and strip paint. A soft wash cleans it without that risk.
• Want it to last longer? Kill the growth at the root instead of blasting the surface. That is what a soft wash does.
• Rather not keep track? The BRIGHT Plan plans the visits around the seasons for you.

How often does a house actually need washing?

About once a year for most Delaware homes, and the right way to do it is soft wash house washing, not a power washer.

CertainTeed, which makes vinyl siding, tells homeowners to clean their siding once a year so buildup never gets a chance to take hold. A yearly soft wash keeps the green from ever getting a full season's head start.

Some homes need it sooner. A house under heavy tree cover, near water, or with a side that never sees the sun can need it more than once a year. The siding tells you. When the green or gray film is back, it is time.

What's the green stuff on the side of my house?

It is living growth, usually algae, mold or mildew feeding on the film of dirt on your siding, and a soft wash house washing kills it at the root.

In Delaware's humidity, the shady north side of a house can go from clean to green in a single summer, and it spreads every season it is left alone. Mildew tends to show up first where rain never reaches, like under the eaves and inside porch enclosures.

If you only have a few spots, mold, algae and stain removal can treat them without washing the whole house.

Why does one side of my house turn green faster?

Shade and moisture: the side that rarely sees sun stays damp longer, and that is the side a yearly soft wash has to keep up with.

Trees make it worse. They drop debris, hold moisture against the house, and block the sun that would dry the siding out. That is why two houses on the same street can need washing on different schedules.

Should I power wash my house myself?

No, not on vinyl, stucco or painted siding: high pressure can blow water behind the panels and strip paint, which is why house washing should be a soft wash.

CertainTeed tells homeowners not to power wash vinyl siding at all, because it can force moisture in, damage the panels or discolor them. Blasting also misses the real problem. Algae, mildew and lichen have roots in the surface, and if you strip the visible growth and leave the roots, it grows back on the same schedule. If you want the side-by-side, soft wash vs. pressure wash breaks it down.

When is the best time of year to wash my house?

Spring and fall, because that is when it shows: most exteriors go a little green in spring and a little streaked by fall, and a soft wash house washing clears both.

If you only do it once a year, do it when the film is back and before it gets another full season to spread. That is also why our BRIGHT Plan, a year-round exterior maintenance membership billed monthly, plans the visits around the seasons. Ask about it when you request a quote.

How do I make a house wash last longer?

Kill the growth instead of blasting it off: soft washing sanitizes the surface instead of just stripping it, so the results last several times longer.

Then keep the conditions that grow it in check. Trim branches back off the siding, keep the gutters flowing so water does not sheet down the walls, and do not let pollen and dirt sit for a whole season.

Your roof runs on a longer clock. Most homes in our service area need roof cleaning every 2 to 3 years, depending on tree cover and shade.

What is soft washing?

Soft washing is low-pressure cleaning with a solution matched to your siding, whether that is vinyl, stucco, brick or another delicate exterior, so it cleans without risking damage.

Every soft wash house washing we do carries our 1-year warranty. Before we start, we rinse and cover your plants, wrap cameras and speakers, and check doors and windows.

What does house washing cost in Delaware?

Every house washing job is quoted after a free walkthrough, because size, height, siding and how far the algae has spread all change the work.

One of us comes out, walks the property with you, and gives you a straight number before anything is touched. If you want to know what moves the price, what exterior cleaning costs walks through it.

Who washes houses in Wilmington and New Castle County?

We do: CT Clean and Son handles soft wash house washing across New Castle County, Delaware, and nearby Pennsylvania.

That covers Wilmington, Newark, Hockessin, Christiana, Greenville, Bear, Middletown and the rest of New Castle County, plus Glen Mills, Garnet Valley, Chadds Ford, Kennett Square and West Chester, PA. If you are close to the city, here is our page on house washing in Wilmington.

We are a father-and-son team, fully licensed and insured, with a certificate of insurance available on request. Call (302) 290-6508 or request a free quote, and we will set up your free walkthrough.

Providing the cleanest, safest and brightest environment possible for your home or business