Most of the damage done to brick by cleaning in New York comes from the machine, not the dirt. A pressure washer set for concrete will cut into a brick face and blow mortar out of its joints. Brick needs far less force than that, and a little more patience.
Brick cleaning is mostly a question of pressure. The Brick Industry Association’s Technical Note 20 says high-pressure water cleaning is not appropriate for brick, and puts the limit at 400 psi measured at the nozzle. NPS Preservation Brief 1 says much the same for older buildings, starting at 100 psi or below. On an NYC wall, going past that risks the brick face and the mortar around it.
As a brick pressure washing contractor in NYC, we start low and raise the pressure only as far as the dirt needs. If you would like to see the result first, we clean a small trial area before the rest of the wall. If the joints or the brick are in poor shape, we tell you before any water goes on, and we seal brick only when it actually needs it. That is what brick cleaning services should mean on an older front.
A dirty brick wall in New York is rarely in danger. A badly cleaned one often is.
These are the mistakes that leave brick worse off than the dirt did.
Too much pressure cuts a brick face and erodes nearby mortar. On NYC brick, BIA Technical Note 20 sets the ceiling at 400 psi.
Dry brick drinks in whatever is sprayed on it. BIA advises soaking the New York wall first so the cleaner stays near the surface.
Abrasive blasting strips a brick’s outer skin along with the dirt. On an NYC front that loss is permanent, and BIA advises against it.
BIA Technical Note 20 rules out unbuffered muriatic acid on brick. On a New York wall, a milder cleaner made for brick is tried first.
Water forced into open joints goes into the NYC wall, not off it. Joints in that state need brick pointing NYC before any washing.
Four points from the Brick Industry Association and the National Park Service that separate cleaning brick from damaging it.
BIA Technical Note 20 calls for saturating the area to be cleaned, and the wall below it, before any cleaning solution goes on, and keeping it wet until the rinse is done. A soaked NYC brick holds the cleaner at its surface instead of drawing it deep into the wall.
The same Note specifies a 25 to 50 degree fan tip held at least 12 inches from the brick, with pre-wetting below 100 psi and rinsing between 100 and 400. A narrow jet held close to a New York wall concentrates force on a small spot, which is how faces get cut.
BIA suggests trial cleaning on about 20 square feet, judged only once the wall has dried, usually after about a week. NPS Preservation Brief 1 goes further and suggests letting a test patch weather for a month or two where time allows. Wet NYC brick always looks cleaner than it is.
Cleaning can draw salts out of brick as a white powder, which Brief 1 notes may need a second treatment. BIA advises removing light efflorescence with a dry or wet stiff fiber brush, after the moisture behind it is fixed. Washing it hard on an NYC wall only feeds more water in.
Before any water goes on the NYC wall, we look at the mortar and the brick. Where joints are open or brick is failing, we tell you, because washing a wall in that state pushes water in and can make the damage worse.
Cleaning begins at low pressure, and the pressure goes up only as far as the dirt requires. If you want to see the result before the whole New York wall is done, we clean a small trial area first and let you judge it once it has dried.
The wall is rinsed at low pressure and left to dry before anyone decides it is finished, since wet NYC brick hides streaks and patches. Sealing is only discussed if the wall actually needs it.
A brick wall that has been cleaned badly can look fine on the day. The trouble shows later, in faces that weather faster where the skin was cut, joints that open a little more each year, and a white bloom that keeps coming back. All of it comes from treating brick like concrete. Soaking the wall, keeping the pressure low, judging the work once it is dry, and saying so when a New York wall needs repair before it needs washing is what leaves the brick cleaner and still whole.
Our brick cleaning services cover row houses and apartment fronts in Queens, Manhattan, Brooklyn and the Bronx, and brick pressure washing reaches older walls in Westchester County and Yonkers too.
Whole buildings in stone, glass or precast are covered under facade cleaning NYC, and the rest of our brick work is on brickwork contractor NYC.
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Yes, if the pressure stays low. BIA Technical Note 20 says high-pressure water is not appropriate for brick, sets the limit at 400 psi at the nozzle, and calls for a fan tip held at least 12 inches away. On an older NYC wall, NPS Preservation Brief 1 advises starting at 100 psi or below.
The name matters less than the pressure at the nozzle. Soft washing usually means a cleaning solution followed by a gentle rinse, which is close to what BIA Technical Note 20 describes for brick, rinsing at 100 to 400 psi. On a New York wall, any method that stays in that range is reasonable.
Usually not. BIA Technical Note 20 advises against abrasive blasting on brick, because it removes the outer surface along with the dirt and the damage is permanent. NPS Preservation Brief 1 calls abrasive methods generally inappropriate on historic masonry. On an NYC front, low-pressure water and a tested cleaner come first.
Not in its raw form. BIA Technical Note 20 says not to use unbuffered muriatic or hydrofluoric acid on brick. Proprietary cleaners made for brick, used as their makers direct and tried on a small area first, are the safer route on a New York wall, and the brick is soaked before they go on.
Usually efflorescence, salts drawn to the surface as the wall dries. NPS Preservation Brief 1 notes that cleaning can bring them out. BIA Technical Note 20 advises brushing light deposits off with a stiff fiber brush, dry or with water, once the moisture source is fixed. On an NYC wall, more washing rarely helps.
Usually not. NPS Preservation Brief 1 says water-repellent coatings on historic masonry are usually unnecessary, are not permanent and must be reapplied, and should never go on a damp wall. On a sound New York wall that sheds water well, we leave the brick unsealed and seal only where it genuinely needs it.
At least until it is dry. BIA Technical Note 20 suggests a trial area of about 20 square feet, judged once dry, usually after about a week. NPS Preservation Brief 1 prefers letting a test patch weather for a month or two where time allows. On an NYC wall, wet brick always looks cleaner.
So it does not soak up the cleaner. BIA Technical Note 20 calls for saturating the area being cleaned, and the wall below it, then keeping it wet through rinsing. Dry brick on a New York wall draws the solution deep inside, where rinsing cannot reach it and it can mark or damage the brick.
