Cleaning Fascia and Soffits: The Trim That Makes a House Look Old Before Its Time

The short answer: low pressure, right chemistry, never aimed up

Fascia and soffit clean up with chemistry and dwell time, not force. The working method is a downstream-injected soft wash: a house wash mix leaving the tip at roughly 40 to 60 PSI, a five to ten minute dwell, then a full rinse. On aluminum, vinyl, and fiber cement, anything past about 500 PSI at the surface starts stripping chalked finish and driving water past the laps. Spray across and slightly downward, never straight up into a soffit seam. A soffit panel is not a sealed surface, and water pushed up through it lands on attic insulation. Work top down: roof edge, fascia, soffit, then the wall below, and rinse the whole elevation before any of it dries. If the surface is in full sun and over about 90 degrees, wet it down first. The mix has to stay wet to do anything at all.

Read the stain before you buy the wash

Four patterns cover most of what we see, and they need different answers. An even gray-brown film across the whole eave is dust. Boise averages under twelve inches of rain a year, so nothing rinses itself, and farm and construction dust settles all summer. That is the easy one; soap and a rinse take it. Chalky white crust on soffit undersides within throw of a sprinkler head is calcium from hard water, and most Treasure Valley taps test somewhere between seven and fifteen grains per gallon. That scale needs a mild acid, not soap. Black speckling concentrated under north-facing eaves is biological and needs sodium hypochlorite in the mix. Vertical dark stripes running down the gutter face are the one to know about: that is bonded road film on oxidized aluminum, and a standard house wash will not touch it. Mud dauber tubes and paper wasp nests get scraped off first, or you just paint the eave with mud.

The four ways people wreck an eave

One: the pressure washer aimed up. A 3,000 PSI fan at a soffit seam pushes water past the panel into the eave, and wet blown-in insulation loses most of its R-value and dries slowly in a closed attic. Two: the ladder set against the gutter. A K-style gutter carries water, not people. The front lip dents under a couple hundred pounds of point load and leaves a permanent shadow line. Use a standoff and a 4:1 angle, base out one foot for every four feet of height. Three: sodium hypochlorite with no pre-wet and no rinse, which browns arborvitae and lawn edges within a day. Four: driving grit into perforated vinyl soffit. Those perforations are the attic's intake air. Code wants roughly one square foot of net free vent area per 150 square feet of attic floor, so a 1,500-square-foot attic is counting on about ten square feet of opening. Plugging or painting them is how you get ice dams and sheathing mold.

What washing cannot fix

Two things a wash will not solve, and we would rather say so before you pay. First, oxidation. Rub a dry thumb across the fascia. If it comes back white, the paint film has chalked, the binder is gone, and you are touching loose pigment. Washing removes that loose layer and evens the color, which reads as a real improvement from the street, but the finish stays flat. No wash restores gloss. Fixing it means an oxidation remover or a repaint, and the repaint is usually the better money. Second, rot. Most fascia in valley subdivisions is a wood board wrapped in aluminum coil, and the wrap hides everything. Press hard with a thumb behind the gutter. If the metal dimples and holds the dent, the wood under it is soft. Decay fungi get going once wood sits above roughly twenty percent moisture, which is exactly what a leaking gutter does. Replacement runs about $10 to $25 a linear foot installed.

Sequence, frequency, and when not to hire this out

Order matters more than people expect. Clean gutters first, because pulling sludge out of a trough sends a black slurry straight down the fascia. Then wash the eaves and walls. Then do the windows last, since a house wash will spot glass. Once a year is enough for most homes, and the natural pairing is the fall gutter clean, which around here lands late October through mid-November after leaf drop. Here is the part that costs us work: if you have a single-story house and the soffits sit eight to ten feet up, do not hire this out. A flow-through brush on a twelve-foot pole runs about forty dollars, threads onto a garden hose, and gets most of a ranch done in a morning. Hire it for a two-story, a steep pitch, peeling painted wood, or real growth. Reflekt's soft-wash house washing is $0.18 per square foot and includes the eaves; gutter cleaning starts at $199.