Commercial Building Washing

The dark vertical streaking down a north or east elevation is not dirt and it does not wash off with water and pressure. It is algae — gloeocapsa magma — and in Michigan it grows on the wall that dries slowest, which is why one side of a building looks ten years older than the other three. Treating it means a cleaning solution that kills the organism, dwell time to let it work, and a low-pressure rinse. Treating it with pressure alone drives water into the substrate, strips paint off block, and it all comes back in a season because the organism is still alive.

Soft wash, not pressure, on anything vertical

Pressure is the wrong tool for a wall. It forces water behind siding and into mortar joints, it etches painted block, it will take the finish off an EIFS panel, and on a two- or three-storey elevation it means someone holding a wand at the top of a ladder fighting the reaction of the gun. Soft washing applies the solution at garden-hose pressure, lets the chemistry do the work, and rinses. The wall gets clean, the coating survives, and the result lasts a season or two rather than weeks.

What the substrate changes

Painted concrete block is the most common commercial wall in Wayne County light-industrial stock and the easiest to damage — the paint is the waterproofing, and once it is off, the block drinks. Face brick can take more but shows efflorescence, the white bloom of salts coming out of the mortar, which is a different problem with a different fix. Prefinished metal panel chalks, so an aggressive clean takes the chalk off unevenly and leaves a patchy wall. EIFS and stucco are the ones people wreck. Which of these you have decides the pressure, the chemical and the order of work, and that gets settled by looking at the building, not over the phone.

Working around an occupied building

A wall wash means water, run-off, a hose across a walkway and a section of the building you cannot use for an hour or two. On an occupied commercial property that is the actual constraint, not the washing. What it needs is a walk of the elevation before the day: where the tenant entrances are, which windows are the ones that leak, where the electrical and the low-voltage penetrations sit, what landscaping is directly below, where the run-off goes and whether that is a storm drain. All of that is a ten-minute conversation at the quote and a bad surprise if it is skipped.

The evidence for this one

Their own photographs include a painted-block industrial elevation with a steel roll-up loading dock door, photographed mid-wash — the clean stripe running down the middle of a dirty wall — and finished, with their rig still on the truck bed. A second set shows a commercial brick elevation with wall-pack lighting and base louvers, carrying heavy dark organic streaking before and uniformly clean brick after. This is work they have done and photographed, not a service line added to fill out a menu.