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Cleaning Equipment

Cleaning Equipment for Masonry Contractors
Photo courtesy of Kem-O-Kleen
The experts don't agree:

"What is the best method for cleaning new and old work?" Not only don't they agree, the extremes are really extreme.

There are at least two very diverse groups when it comes to discussing cleaning equipment for restoration, renovation and even new work clean up. On the one hand, some feel that high-pressure (2,000 and even 3,000 psi) washers are the best, while the opposite camp goes for low-pressure (50-90 with 700 maximum psi) units with special chemical solutions. Without drawing a line in the sand, here are some of those expert opinions.

Tools for Masonry Contractors
Photo courtesy of Mi-T-M Corp.
"Water washing by itself with a pressure washer is going to be the most effective and efficient method of cleaning in a limited amount of time," said Matt Hoefer, equipment division manager for Mi-T-M Corp of Peosta, Iowa. Mi-T-M has been making pressure washers since 1971. "Adding a solution into the system can help in certain applications, but it can also harm the product. If you're not careful when using solutions, you risk damaging the color and integrity of the masonry by washing away the sand and texture on the surface. The same is true when using too much pressure."

"We don't suggest pressured water to apply chemicals, either with mixtures or alone," retorted Jim Diedrich, president of Diedrich Technologies in Milwaukee, Wisc. Diedrich Technologies makes chemical solutions to clean old and new masonry. "It's even written in certain guidelines and specifications put out by brick manufacturers. They say that the pressure system for applying water should not be the same system for applying chemicals because you would cause such deep penetration with the chemicals that you'll never be able to get them washed out thoroughly."

Hoefer agreed, "If you are going to use chemical solutions, we recommend injecting those solutions on a low pressure basis. This allows the solution time to work. There are a couple things to remember when using solutions. First, make sure the solution you are using is pressure washer safe; most solutions will say whether they are or not. If the solution is not pressure washer safe, you can apply it with a separate low-pressure sprayer. Another thing to remember when using solutions for cleaning is to make sure the solutions are safe for the area you are cleaning."

Tools for Masonry Contractors

Tools for Masonry Contractors
Tools for Masonry Contractors
Photos courtesy of Prosoco
Diedrich feels high-pressure equipment for applying chemicals with water are good for truck washing and maybe for removing grease off floors, but not for new masonry or building restoration cleaning. "Because you're spraying acids at 2,000 psi, those acids go so deep into the work that you can never neutralize them and they will remain dormant until activated by some other contaminants and they'll come out as a brown caramelized iron stain. We recommend a unit that sprays at 50 psi, which is the limit most brick manufacturers use when they put out specifications — they don't want to see these acids or cleaners applied with deep penetration."

That's a very low pressure, and few companies make commercial or professional-grade washers at that rating. However, one that does is Restoration Direct, located in Harrisburg, Pa. Robert Port, vice president of engineering, explained, "Contractors love our air-powered Cobra sprayers. They are operator adjustable from 20 to 90 psi, so you don't waste chemicals or have too deep a penetration into the masonry. We fit the sprayers with either single or dual pumps; the second pump is really just for backup, although few have been needed since the pumps are so durable. Two operators can use one pump for even faster work."

"By using the variable output nozzle, you can spray one quart to three gallons per minute," he continued. "And the operator can use the sprayer up to 10 stories without moving the unit from the ground."

Pressure, Volume and Speed
Going into more detail is Randy Weil, president of Kem-O-Kleen in Denver.

Tools for Masonry Contractors
Photo courtesy of Kem-O-Kleen
"There are three things to consider when thinking about cleaning equipment for restoration: ability to adjust water pressure, ability to control the delivery of chemicals and speed," he said. "The ability to control the water pressure is important because materials vary job to job. Softer brick and stone will tolerate less water pressure than harder materials. Hot water will clean better because it will activate the chemicals and because it will dry faster, allowing less absorption into the brick and stone.

"If chemicals are not applied consistently, the outcome won't be consistent," he continued. "Two problems need to be addressed in chemical delivery: consistent dilution prior to application and consistent application. Typically, chemical delivery is accomplished by brush-and-bucket, garden-type sprayer, or automated spray systems. The first method, brush-and-bucket, has risks in the consistency of chemical dilution bucket to bucket, and that is further compounded by the risk of uneven application with the brush. Garden sprayers are better, but still present some application risk as pressure drops and is then restored.

"The best solution for consistent application is an automated spray system capable of handling strong acidic chemicals. These systems have the benefit of mixing large quantities (20 gallons) of chemical in the proper dilution, and maintaining consistent pressure as the chemical is applied. This type of automated spraying system is standard with washers made specifically for cleaning masonry."

Speed is important for several reasons, with the most obvious being minimizing job costs.

"Fast machines do not fatigue the operator and let you be more productive and profitable," Weil said. "Automation also helps you meet tight deadlines. A more subtle benefit of an automated solution is the higher consistency achieved when all or a large part of the job is done at once, rather than over many days, and when the operator can focus on the quality of the work rather than an aching back."

Worker Fatigue
Ergonomics and operator fatigue problems shouldn't be overlooked, agreed Lynn Peden, owner of EaCo Chem of Forestville, Pa. EaCo Chem focuses on brushless chemical cleaners for new and restoration masonry work.

Tools for Masonry Contractors
Photo courtesy of Kem-O-Kleen
"The biggest problem with pressure washers isn't the pressure (psi) but the operator training," Peden said. "If the operator uses too much water on the job, that is both wasteful of the water and stressful for the worker. While some people claim you should use a maximum of 500-700 psi with the pressure washer, that's only one factor in the equation."

Peden uses a formula for determining the best combination of pressure and nozzle that results in a unit proper for the work at hand. "The formula is simply gallons/minute times psi equals cleaning units (CU). So if you have a 2,000 psi washer and use a four-gallon/minute nozzle, the CU is 8,000. That should be good for most masonry cleaning. When you are done, however, the rinse cycle, as it were, does require a higher pressure wash. Here, high psi comes in handy to wash out chemicals using a five- to seven-gallon/minute nozzle."

Whoa, says Hoefer of Mi-T-M. "The general rule of thumb when cleaning masonry is that psi is more important than gpm (gallons per minute). We would recommend at least 1,500-2,000 psi. Higher psi can be used, but it is important to keep the nozzle at a greater distance from the work area so that you do not cut into the masonry or destroy the integrity of the masonry joint. Start with a 40-degree tip, which is the widest of the spray pattern. As you get a feel for it, you may be able to go to a 25-degree tip for a deeper cleaning."

If you attend Masonry Showcase or any of the other masonry trade shows, you've most likely seen Prosoco's booth and met Gary Henry, Prosoco's business communications specialist.

"One of the big problems that contractors run into in the field is inexperienced workers using too much pressure to pre-wet and rinse masonry walls," Henry said. "They'll take a pressure washer on a new masonry wall trying to knock the excess mortar off. They'll hit it with 3,000 psi sometimes, and get right up close on it. That leaves wand marks all over the wall that won't come off and it blows out mortar joints. That is a terrible problem: people using too much pressure and not enough water to rinse walls."

Not so fast, said Diedrich. "The nice way to do this is about five gallons a minute at 1,000 psi. That's what I used to use 36 years ago. Never did any damage and was easier to work with. It was great."

He added, "A lot of this has to do with nozzle tips. Pressure washer users are demanding faster, bigger, more efficient systems. Now everybody is looking into oscillating tips, which are like machine gunning the dirt or paint off. It looks like a normal pressure washer but it isn't — it's a bull's-eye pressure water concept, which can damage severely. There are articles written where guys have just totally destroyed buildings using these systems. If you get a good unit, they come with a set of nozzles: 15, 25 and 40 degree. My suggestions are always start with the 25-40 degree fan tips with 1,000 psi or less and five gallons a minute."

Tools for Masonry Contractors
Photos courtesy of Prosoco
Taking a different tack is Weil. "High pressure water alone doesn't compare to the results of a hot chemical/water mixture. The chemical is activated by the heat — for every 35 degrees the acid temperature is increased, it becomes twice as active. The chemical does the work without damaging the brick face. Without using a chemical, one is depending on erosion for cleaning. In comparison, erosion will either leave mortar residual or, if the operator keeps blasting water, the risk of damage to brick face, mortar joints or both increases dramatically. The Kem-O-Kleen washer provides the operator with heated high pressure water for initial wet-down and final rinse, chemical-water mixture for cleaning, and hot water for the final rinse."

Since Prosoco makes a line of cleaning solutions, Henry's next comment is expected. "What we recommend is using a good proprietary masonry cleaner that's going to do most of the work of getting the stuff off the wall for you. Then you don't have to use super high pressure that can damage the masonry and joints. We recommend no higher than 1,000 psi to rinse down a cleaned masonry wall. Anything more than that and you take a chance of putting marks on that wall and harming the joint."

He added: "It's not commonly known but it's not really the pressure that does the work for you, but the amount of water you put on the wall. We recommend pressure washing equipment that is going to allow you to put six to eight gallons per minute on that wall. If you do that you are going to thoroughly flush that wall of any residues, dissolved contaminants and spent cleaners, and you are going to get great looking results."

That covers the new work aspects of cleaning. What about restoration? "On restoration jobs it's probably more important than ever to control your psi with the pressure wash," Henry said. "That masonry is often even more sensitive than your new brick and block. On new brick and block, we can pretty much make a blanket recommendation of between 500-1,000 psi, six to eight gallons per minute. On a restoration job every one of those is going to be a little different. As a general rule you want to use a lot of water and limit your psi, but you also want to test before you do anything. And you always want to error on the side of caution. You really don't want to error at all."



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