Power Washing in Vienna and Northern Virginia

The green and black film on the shaded side of a house is not dirt. It is living growth, algae and mildew, and it has roots into the surface. Blasting it removes what you can see. The organism is still there, which is why a pressure-only wash looks great for two months and then goes green again faster than you expect.

Soft washing means applying a cleaning solution at low pressure, letting it dwell so it actually kills the growth, then rinsing at low pressure. It cleans deeper, it lasts noticeably longer, and it does not stress the surface. On vinyl siding, painted wood, stucco and anything with a coating on it, that is what the job should be.

The other thing detergent solves is chalking. Older vinyl and painted surfaces oxidize, leaving a fine powder that comes off on your hand. Pressure alone smears it. If you are painting afterward, that chalk absolutely has to come off, because a coating applied over chalk is a coating with a layer of loose powder underneath it, and it will let go.

Every material has its own rules. This is roughly how we approach the common ones.

• Vinyl siding: low pressure and detergent, always washing downward or level, never angled up under the laps. Water driven up behind siding has nowhere to go and ends up in the wall.
• Painted wood siding: gentle. Enough to remove dirt, mildew and any loose failing paint, and no more. If paint comes off during a wash it was already failing.
• Stucco: low pressure. Stucco is porous and a narrow tip will erode the surface and force water into the wall system. Cracks get noted, not power washed.
• Brick and masonry: moderate at most, kept off the mortar joints. Old lime mortar is soft and can be washed right out of a wall.
• Concrete driveways and patios: this is where higher pressure belongs, with a rotating surface cleaner rather than a bare wand.
• Pavers: careful pressure, since aggressive washing strips the joint sand and you will need to re-sand afterward.
• Wood decks and fences: low pressure with a wood cleaner. Softwood furrows easily and wand marks are permanent.
• Composite decking: cleaner and low pressure only. High pressure can raise the surface texture and it will not go back.

Here is something worth knowing before you rent a machine for a weekend. Concrete washed with a bare wand almost always ends up striped, that zebra pattern of clean and less clean bands across a driveway. It happens because a wand cleans in an arc and no human hand keeps the distance and overlap perfectly consistent across a whole slab.

The fix is a surface cleaner, the round attachment that rides flat on the concrete with spinning jets inside a housing. It holds the same distance across the entire surface and produces an even result, faster and with less water. It also keeps the spray contained instead of throwing dirt across your garage door and the side of your car.

Not all stains come out with pressure. Oil and transmission fluid need a degreaser and time to pull out of the pores. Rust from a fertilizer spreader or metal furniture legs is chemical and needs a rust remover, not force. Tannin stains under an oak tree are a different treatment again. If a stain has been in bare concrete for years, we will tell you honestly whether it will lighten or truly disappear, before we start rather than after.

When a wash is prep for a paint job, the bar is higher. Clean enough to look nice is not the same as clean enough to accept a coating. Every bit of dirt, pollen, mildew and chalk has to come off, because paint bonds to what it touches, and if it touches a layer of chalk, that is what it is stuck to.

We also give the house time to dry after washing. Wood especially holds water well after the surface looks dry, and painting onto damp siding traps moisture under the film, which shows up later as blistering and peeling. Depending on the season and the material, that means one to several days between the wash and the first coat. It is a real part of the schedule, not a delay.

One thing homeowners rarely know: pressure washing does not kill mildew as thoroughly as a cleaning solution does, and mildew that survives under a fresh coat of paint keeps growing and comes back through the new film. If your north side went green last year, it will do it again through new paint unless it is treated properly first. That is a chemical step, not a pressure step.

It is worth setting expectations before we roll a hose out, because a few things look like dirt and are not.

Faded paint is not dirty paint. Ultraviolet light breaks down the resin in a coating over the years and the pigment chalks off. Washing removes the chalk and can make a wall look slightly better, but the color that is gone is gone. That is a repaint conversation.

Weathered gray wood on a fence or deck will lighten with cleaning, but the gray is damaged surface fiber and getting the real wood tone back takes a cleaner plus a brightener and usually sanding.

Efflorescence, the white powdery bloom on brick and block, is mineral salt coming out of the masonry as moisture moves through it. Water will not remove it for long, because more moisture keeps bringing more salt to the surface. It needs the right treatment and, more importantly, an understanding of where the water is coming from.

Artillery fungus, those tiny black specks all over the lower siding of a house with hardwood mulch beds, is stubborn. The spores bond hard to vinyl and paint. Some of it comes off. Some of it does not, and anyone who promises otherwise has not scraped many of them off a wall.

We would rather tell you this at the estimate than have you look at a clean house and wonder why one thing is still there.

Water goes places. Before we start we walk the site with you and cover what needs covering.

Plants and shrubs get soaked with clean water before any cleaner goes up, which keeps them from taking up the solution, and rinsed thoroughly afterward. Light fixtures, outlets, doorbells and cameras get protected. We check that windows and storm windows are shut, and we point out any that do not seal, because an older window can leak with a garden hose let alone a washer.

We keep water away from soffit and attic vents, ridge and gable vents, and dryer vents. We do not blast up into the underside of a roof edge. And we do not pressure wash roof shingles, because it strips the granules that make the shingle a roof. A roof that is streaked with algae needs a soft wash approach and, honestly, a roofer's opinion if it is old.

We watch the temperature too. Washing in freezing weather leaves ice on walkways and steps, and cleaning solutions do not work properly when it is cold. Late fall and winter jobs get scheduled around that.

Most house washes are a single day. Concrete flatwork is often half a day. Decks are washed as part of a refinishing job, with drying time built in before we sand and stain.

Spring is our busiest stretch, once the pollen has finished falling in this area, since a house coated in yellow-green film is the reason most people call. Early fall is the quieter, easier window if you have a choice. Either way, the same crew arrives at the same time and Fred is there with them.

Our week runs 8 to 5, Monday through Friday, and we will book a weekend by appointment. Veterans get 10 percent off, and so does anyone 65 or older. If you are considering painting later in the year, tell us at the wash and we will note what we find on the walls, since a wash is the best possible chance to look at every square foot of a house up close.

Call 703-869-0593. We serve Vienna, Oakton, McLean, Great Falls, Arlington, Falls Church, Tysons, Fairfax, Burke, Reston, Herndon, Annandale, Alexandria and Springfield.