The green film on Bellevue siding is algae, and the safe way to remove it is a soft wash: a cleaning solution applied at low pressure, left to work, then rinsed off. Fall is a good time to do it. A humid summer's growth is at its worst, and there is still time to wash and dry the house before December, January and February, the months that average below freezing here.
Here is where the green comes from, why a pressure washer is the wrong tool for siding, and what a house wash costs.
What the green on your siding is
Most of the green on siding is algae, the same kind of growth that streaks roofs. The Asphalt Roofing Manufacturers Association notes that roof algae travels through the air and grows best where conditions stay warm and humid. On siding it shows up where a wall stays damp the longest:
- North facing walls, which get little direct sun to dry them
- Walls under trees, where shade and dripping leaves keep them wet
- Low on the wall behind shrubs, where air does not move
- Below gutters that overflow, where water runs down the same spot every storm
Gray or black specks that do not rinse off with a hose are often mildew. Dust and cobwebs collect under the eaves and around lights. A house wash takes care of all of it.
Why Bellevue siding turns green
Bellevue has more mature trees than most of the metro. Homes near Fontenelle Forest, Haworth Park and the bluffs along the Missouri River sit under oaks, maples and cottonwoods, and shaded walls stay wet for hours after rain and morning dew. We are based in Bellevue, and the greenest siding we see is on the north side of houses under tree cover.
Soft washing, not pressure washing
The Polymeric Exterior Products Association, the trade group for vinyl siding makers, says routine cleaning of vinyl siding only needs soap, water and a soft-bristled brush. It allows a power washer only with caution: hold it straight at eye level and never aim it upward, because that can force water behind the panels. Some siding manufacturers do not recommend power washing at all, and others limit the pressure and the cleaners you can use.
That is why we soft wash siding. The cleaning solution does the work, not the force of the water. Our pressure washing service matches the pressure to the surface:
| Surface | How we wash it |
|---|---|
| Vinyl, fiber cement and painted siding | Soft wash, low pressure |
| Roofs | Soft wash, never high pressure |
| Wood decks and fences | Low pressure |
| Driveways, sidewalks and patios | Higher pressure |
How a house wash works
- Treat. We apply a cleaning solution matched to the surface that loosens algae, mildew and dirt before any pressure touches it.
- Wash. Low pressure only, in even passes.
- Rinse. Everything gets a full rinse, including your windows, plants and walkways.
You do not need to be home. We need an outdoor spigot and unlocked gates. Move cars and patio furniture away from the walls if you can, or we can do it for you.
Why fall is a good time
- The summer growth is done. Algae spreads through the warm, humid months, so a fall wash takes off the whole season's worth.
- There is still time before the cold. December through February are the only months with an average temperature below freezing in the Omaha area (NOAA 1991 to 2020 normals). A wash in late September, October or early November leaves time for the walls to dry.
- A clean house all winter. You look at that siding every day until spring, and so do holiday guests.
Do the siding before the glass. We wash the house first and clean the windows after, so you get one visit and one clean result.
How often to wash
Most homes do well with a house wash every one to two years. Homes under heavy shade, or with a north wall that greens up fast, are the ones worth washing every year.
What a house wash costs
A house wash with Fontenelle runs $300 to $800+, depending on the size of the house, the siding and how much buildup there is. If the roof has black streaks too, a roof wash runs $500 to $1,200+; our guide to roof soft washing vs pressure washing explains how it works. Stains on the siding below a gutter are a sign it is overflowing, so add a gutter cleaning in Bellevue to the same quote. A window cleaning afterward runs $11 per pane inside and out, or $7 per pane outside only. Members of our membership program save 15% to 30% on every cleaning.
Getting a quote
Send us your address and a photo of the worst wall if you have one. Request a free quote and we will text you a price, usually within the hour.
Want the crew to handle it?
Fontenelle Window Cleaning serves Omaha, Bellevue, Papillion and the whole metro. Free quotes by text, usually within the hour.
