Archive for the ‘Masonry Cleaning’ Category

Our very own John Young, PROSOCO’s digital marketing manager, went on location at Topeka (Kan.) High School recently to shoot footage of the restoration of the building’s historic brick and limestone exterior.

Topeka-based Restoration & Waterproofing Contractors Inc. got the nod for the job, which showed years worth of atmospheric and biological stains as well as smoke residue from a fire a few years back. RWC Project Manager David Falley used PROSOCO’s Enviro Klean® SafRestorer to safely remove stains around the building’s intricate architectural details and give the facade a brighter, cleaner appearance.

Watch the dramatic before-and-after shots in this video:

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Liberty Memorial

The most prominent feature of Kansas City’s Liberty Memorial is arguably its 217-foot-tall tower. Photo courtesy of Structural Engineering Associates

This year marks the beginning of the centennial observance of World War I, 1914-1918. The heart of that observance stands in the heartland — at Kansas City’s Liberty Memorial, a registered National Historic Landmark and home of the officially designated World War I museum of the United States.

So to call a project to clean and restore such a monument a great undertaking is… greatly understated. And it also takes time.

One iteration of the monument’s restoration began in 2000, when subcontractor Mid Continental Restoration Co. (along with general contractor JE Dunn Construction and a bevy of architects and engineers) used PROSOCO products to clean the memorial. They installed about 13,000 cubic feet of new stone, and cleaned and replaced around 24,000 cubic feet of existing limestone.

By this time, Liberty Memorial was a well-known site to PROSOCO. Its representatives had conducted surveys on the stone and also removed graffiti in the 1980s.

So when an army of designers and contractors undertook a $1.35 million masonry restoration project in 2012 to clean and protect the mostly limestone exterior of the complex, PROSOCO was ready for the call.

If you haven’t ever visited, put the Liberty Memorial on your list the next time you’re in Kansas City. Its stunning aesthetics have been part of the town’s cityscape since its dedication by President Calvin Coolidge in 1926.

The Liberty Memorial overlooks downtown Kansas City.

The Liberty Memorial overlooks downtown Kansas City. Photo courtesy of National World War I Museum at Liberty Memorial

The monument, designed by Harold Van Buren Magonigle in an Egyptian Revival architectural style on 47 acres, includes a 217-foot-tall tower, two Assyrian sphinxes, the 488-foot-by-48-foot Great Frieze on the North Wall, the Dedication Wall and many more elements constructed of limestone.

Under a design team led by Gould Evans and in conjunction with General Contractor JE Dunn Construction, two Kansas City firms — Structural Engineering Associates and Susan Richards Johnson & Associates — worked in collaboration to complete the limestone restoration. That included cleaning and sealing of the main entry, tower, General’s Wall and fountains, south entry courtyard, sphinxes, and the Great Frieze on the North Wall.

A variety of sources and types of limestones comprising the massive structure complicated the scope of the project. There was limestone old and new, buff and variegated, from different sections of quarries and varying grades. But it wasn’t too much for PROSOCO’s EnviroKlean ReKlaim (formerly known as BioKlean), ReVive (formerly known as BioWash), OH100 Consolidation Treatment, SureKlean Weather Seal Natural Stone Treatment and more.

Liberty Memorial tower

Photo courtesy of Structural Engineering Associates

Kirk Matchell, restoration project manager and associate at Structural Engineering Associates, said that PROSOCO products were specified almost exclusively in the publicly bid restoration job.

“We had worked with PROSOCO’s products for many many years,” Matchell said. “(The products) did wonderfully. They took care of all of the stain issues, and we (applied) a really good water repellent. It’s holding its color, and it’s done what we’ve asked for it to do.”

For Julie Garvey, project designer of Susan Richards Johnson & Associates, familiarity with PROSOCO’s cleaning and protective treatments played a crucial role in those products getting into the specs.

Mike Dickey of Dickey Sales LLC, a manufacturer’s sales rep for PROSOCO, had volunteered to perform a test sample for the firm, “so that we could determine the efficacy of the product… and make sure that no damage or detriment would be seen with the product on the stone in the long term,” Garvey said.

The sample, conducted a full year before construction began, tested 10-year-old Indiana limestone that had been experiencing severe discoloration due to mildew and staining. On the right-hand side of the sample (pictured), the control was power-washed with warm water. The left side of the sample was cleaned with ReKlaim, followed by an application of EnviroKlean Revive (formerly known as BioWash). On the lower half of the left side, a consolidant (OH100) and PROSOCO’s SureKlean Limestone & Masonry Afterwash was applied to demonstrate that “the product would not discolor or darken the stone in any way.” Garvey and others from the firm, including Project Architect Angie Gaebler, watched the three sections as they were left exposed to the elements for a full year.

Test panel at Liberty Memorial

The test panel at Liberty Memorial included the control panel (right), which was power-washed, and the left-side panel, which was treated with PROSOCO’s ReKlaim and ReVive cleaners. They were found to safely remove biological and atmospheric staining on the limestone. Photo courtesy of Susan Richards Johnson & Associates

A year later, Garvey said they “saw significant improvement in the overall appearance of the stone, it was not discolored, and the area was remaining clean longer. There were no detrimental effects of the water repellent or cleaning treatments, and we approved those for the Liberty Memorial.”

Construction started in 2012 and was completed late last year, but the work of everyone involved didn’t go unnoticed. The restoration of the memorial’s Wall of Dedication earned a 2012 Preservation Award in the conservation category from Historic Kansas City, a nonprofit dedicated to preserving the city’s buildings of “historical, cultural or architectural significance.” This wall commemorates the five allied leaders — Lt. Gen. Baron Jacques of Belgium; Admiral Earl Beatty of Great Britain; Gen. Armando Diaz of Italy; Marshal Ferdinand Foch of France; and Gen. John Pershing of the U.S. — who attended the memorial’s groundbreaking ceremony in 1921.

In addition, the overall masonry repairs of the memorial garnered an award of merit from the International Concrete Repair Institute in the historic category.

But it didn’t take international awards for the project’s architects to take pride in the finished product. “It was a labor of love,” Garvey of Susan Richards Johnson & Associates said. “We’re truly honored to have been part of such a significant historic property here in town.”

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Dave Pennington, head of PROSOCO's Building Envelope Group, ponders the trophies he won Sept. 5 at a competition hosted by the San Antonio Masonry Association.

Dave Pennington, head of PROSOCO’s Building Envelope Group, ponders the trophies he won Sept. 5 at a competition hosted by the San Antonio Masonry Association.

Photos by Al Morris

PROSOCO picked up three firsts and a second in competitions held Sept. 5 by the San Antonio Masonry Association, and we never even needed our Sure Klean masonry cleaners.

That’s because the competitions didn’t involve brick, block or stone masonry. Instead, the contests, held at the San Antonio Masonry Association’s annual Barbecue and Gun Shoot aimed to find who could smoke the best meat, and create the best desserts and other concoctions.

Al Morris, PROSOCO’s National Sales Manager, reports that PROSOCO’s ace smoker and Building Envelope Group Leader Dave Pennington captured honors in four of eight contests, including first-place chicken; first-place dessert, first-place chef’s choice and second-place brisket.

Dave won the honors in the meat categories, Al says, with his proprietary mix of spices, known as a “rub,” because you massage the mix into the meat before smoking — a time-honored barbecuing tradition in Texas.

Dave Pennington prepares his first-place "Chef's Choice" smoked red cabbage dish at the San Antonio Masonry Association's annual Barbecue and Gun Shoot, Sept. 5.

Dave Pennington prepares his first-place “Chef’s Choice” smoked red cabbage dish at the San Antonio Masonry Association’s annual Barbecue and Gun Shoot, Sept. 5.

Dave captured chef’s choice honors with his smoked red cabbage dish, which included bacon, corn, onions, and jalapeno and red peppers.

His dessert, Al said, was a kind of smoked cream pie including butter, brown sugar, cream cheese, walnuts and crumbled butter cookies.

“I don’t know exactly what it was,” Al said, “except it was delicious.”

Masonry professionals from the San Antonio area attended the barbecue and gun shoot. Dave faced off against six competitors to bring home the smoking honors.

“Many masonry buildings cleaned with PROSOCO’s masonry cleaners have won design and construction awards — including PROSOCO’s own Lawrence, Kan., headquarters,” Al said. “This may be the first time we won a masonry association’s competition without them.”

A guest at the San Antonio Masonry Association's annual Barbecue and Gun Shoot checks messages before diving into succulent smoked chicken and brisket.

A guest at the San Antonio Masonry Association’s annual Barbecue and Gun Shoot checks messages before diving into succulent smoked chicken and brisket.

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Foreman Ed Erazo, SparkleWash Construction Services, Omaha, Neb., uses low pressure spray to apply Sure Klean Vana Trol masonry cleaner to a mixed masonry elevation at an under-construction shopping center in Papillion, Neb. photo courtesy Craig Christensen

Foreman Ed Erazo, SparkleWash Construction Services, Omaha, Neb., uses low pressure spray to apply Sure Klean Vana Trol masonry cleaner to a mixed masonry elevation at an under-construction shopping center in Papillion, Neb. photo courtesy Craig Christensen.

The editor of a construction trade magazine called the other day.

She wanted to understand masonry cleaning, since she planned to feature this important but not-so-well-understood facet of masonry construction in an upcoming issue. She wasn’t afraid to ask about the basics, either.

She sent me a list of questions. I answered them, and after checking my answers with our in-house experts, returned the list.

Here’s the masonry cleaning Q & A:

What is the cleaner supposed to do? Simply remove excess mortar, dirt and grime from the surface of the brick, stone or CMU? Or more?

Cleaners for new masonry construction remove dried mortar smears and splashes from the masonry. They “clarify” mortar joints, removing the bit that has bulged out during tooling, so the joint has nice neat edges. On colored concrete block masonry, good cleaners also improve “color uniformity” building-wide.

This photo shows the basic purpose of new construction cleaning -- remove excess mortar and clarify mortar joints. The contractor used Sure Klean 600 new masonry cleaner to do the job.

This photo shows the basic purpose of new construction cleaning — remove excess mortar and clarify mortar joints.

Restoration cleaners remove a host of contaminants from historic building fabrics, from biological staining to atmospheric soiling from decades of air pollution caused by cars and factories.

New construction cleaners and restoration cleaners should do their jobs without damaging the masonry.

This before-and-after photo shows restoration cleaning under way on a 1928 apartment building in Gary, Ind.

This before-and-after photo shows restoration cleaning under way on a 1928 apartment building in Gary, Ind.

What isn’t it supposed to do? Sink into brick and mortar joints, because that could cause what?

Above all, cleaners should not damage the masonry. Other things they shouldn’t do include staying on the surface too long. They can dry out and become one more unsightly contaminant, especially if they contain dissolved mortar or other soiling. If applied at too high a pressure, they can penetrate the masonry too deeply to be rinsed away. If the cleaner starts to dry before the dwell is complete, reapply.

What do you mean by masonry “substrates” when talking about the mock up panel?

Whether referring to a test or mock-up panel, or the building itself, “substrate” is jargon for the particular kind of masonry material. For instance, clay brick is one kind of substrate, and concrete brick is another.

When is the bucket and brush method needed? Is that ever the best choice?

Bucket and brush is appropriate for indoor cleaning where water must be tightly controlled. Also for cleaning isolated areas and features outside. Bucket and brush doesn’t distribute the cleaner as uniformly over a large area as low-pressure spraying, however.

This is a good place to mention the 4-step method for masonry cleaning.

Why was raw acid ever used? Why isn’t it anymore? Was it always muriatic?

Pre-World War II, masonry pretty much meant red clay brick and gray mortar. Red clay brick is highly acid-resistant, so to clean the acid-soluble excess mortar, masons used cheap, abundant muriatic acid, a by-product of steel manufacturing.

Since then, manufacturers have developed an enormous range of masonry products, in all colors, both clay and acid-soluble concrete. Ingredients to create colors and effects in clay brick, such as vanadium salts (beige brick) or iron (iron spot brick), for example, can react with acid to mobilize ugly stains. So manufacturers created cleaners that use only tiny amounts of acid, controlled and enhanced with detergents and buffering agents.

These proprietary cleaners, made specifically for cleaning, come with precise application and safety instructions, and warranties. Follow directions, and you can count on the result. This is not the case with muriatic acid, which is just a byproduct, and never intended for masonry cleaning. It has no warranty, safety or application instructions, let alone any kind of tech support.

The good news - the applicator saved a couple bucks by using cheap muriatic acid to clean the masonry. The bad news - Cleaning with muriatic acid caused these ugly stains which equal thousands of dollars in damage.

The good news – the contractor saved a couple bucks by using muriatic acid to clean the masonry. The bad news – Cleaning with muriatic acid caused these ugly stains which equal thousands of dollars in damage.

As a byproduct, it contains impurities, which accounts for the yellow color. These impurities can stain mortar joints during cleaning.

Muriatic acid is cheap and abundant which is why some contractors use it, even though the Brick Industry Association, Mason Contractors Association and other industry groups have come out hard against muriatic acid. Many brick manufacturers include pallet tags with their products expressly warning against cleaning with muriatic acid. But old habits die hard.

Is there a maximum PSI for water pressure?

For rinsing masonry, 1,000 psi is probably as high as you want to go. Again it’s quantity of water used (gpm) rather than psi that governs the effectiveness of the rinse. The higher the psi, the more chance you have of scarring the masonry with “wand marks.” In the dimensional stone industry, as you may know, super-high psi is used to cut stone.

Another element to consider in pressure rinsing is the radius of the spray, commonly referred to as the “degree of fan.” A thousand psi at zero degrees of fan would basically be a laser beam, scarring the masonry. The same psi at 40 degrees of fan (recommended) will give you a good rinse.

PSI also refers to the water just as it leaves the nozzle. The stream loses some of its velocity between nozzle and wall. Keeping the nozzle about 18 inches from the masonry is recommended.

High pressure and a narrow fan have scarred this concrete masonry -- without doing a very good  job of cleaning,

High pressure and a narrow fan have scarred this concrete masonry — without doing a very good job of cleaning,

If a cleaning plan is discussed in pre-construction, should it also be specified?

The cleaning plan should always be discussed pre-construction, and proper products and procedures specified. It isn’t always, and projects often pay the price.

Whose job is it to design the cleaning plan and to approve of the job when done?

G.C., architect, mason and cleaning sub should work together to design the cleaning plan, with input from the masonry manufacturer. Whoever has overall responsibility to deliver the building to the client – usually the architect — should approve the completed project.

Is the cleaning typically done by the mason contractor or is that work sub-contracted out?

It can and is done either way. If sub-contracted, the mason contractor still needs to ensure proper products and procedures are used.

Bad cleaning looks bad but may also damage masonry. How?

On clay masonry, some forms of improper cleaning, like using muriatic acid or not properly pre-wetting or rinsing can etch mortar joints. Exposing the softer layers beneath the surface decreases the mortar joint service life by making it more vulnerable to freeze-thaw cycling and other forms of deterioration. Eventually, water gets in the building envelope.

The same can happen with concrete masonry, only the CMU is also vulnerable along with the joint.

Above all, cleaners should not damage the masonry. Here, a cleaner not made for concrete masonry etched the joints and the block surface.

Above all, cleaners should not damage the masonry. Here, a cleaner not made for concrete masonry etched the joints and the block surface. In addition, the masonry was likely not properly pre-wet or rinsed.

Does masonry with a water repellent coating need different treatment than “raw” masonry?

New-construction cleaning – removing excess mortar and clarifying mortar joints – should be conducted before applying a water repellent. A finished building with a water-repellent applied will still need maintenance cleaning. But this will be a different type of cleaner than used for new-construction cleaning, because the soiling to be removed is different.

In general, maintenance cleaners are less complex and less aggressive than new construction cleaners.

Is it appropriate to ask about cleaning historic or existing buildings?

Yes, because anything outside gets dirty and needs to be cleaned — especially after half a century or so.

Anything outside gets dirty -- just how dirty a building can get is shown here during restoration cleaning of Chicago's Randolph Tower.

Anything outside gets dirty — just how dirty a building can get is shown here during restoration cleaning of Chicago’s Randolph Tower, with PROSOCO’s Sure Klean Restoration Cleaner, natch.

Is that process different?

The basic procedure – soak or “prewet” the surface; apply the cleaner; dwell and agitate; rinse – is usually the same for restoration and maintenance cleaning as it is for new construction cleaning.

Is the product used different?

The products are different from new-construction cleaning, because the contaminants and masonries are different. You always want a cleaner specifically designed for the masonry you’re cleaning and the contaminants you’re removing. Just as there are different products for different kinds of new construction cleaning – clay and concrete, for instance, so there are different kinds of cleaners in restoration cleaning for, say, granite and limestone.

Removing biological soiling from old acid-soluble limestone takes a much different kind of cleaner than removing dried mortar from new acid-resistant clay brick.

Can you list, generically, the best kinds of products for different masonry materials (one for brick, another for block, another for limestone, etc) without using brand names?

Your best bet for cleaning any kind of new masonry is to locate a cleaner designed for that specific kind of masonry. Cleaning red clay brick? There’s a cleaner made for it.

Cleaning cast stone (a concrete product)? Use a product specifically designed for cast stone.

Removing atmospheric soiling from 100-year-old limestone? Make sure the cleaner is designed specifically for that chore.

If you’re in doubt, call the manufacturer’s toll-free customer care number. If there is no number, don’t use that product. Use only cleaning products backed by free, readily available manufacturer tech support.

The cost of damaging a building is too great to be anything but one hundred percent certain that you’ve got the right cleaners and procedures.

If you see one product that claims to clean every kind of masonry – and there are some out there – run. One product cannot clean every kind of masonry and every kind of soiling any more than one kind of saw can cut every kind of material, or one kind of hammer can do every construction job.

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This totally permeable cheesecloth, treated with masonry water-repellent Weather Seal Siloxane PD, illustrates what protective treatments are all about. Liquid water cannot go through the treated cloth, porous as it is, and beads up on the surface. Water vapor can go through, however, as the rising steam shows.

I first learned about penetrating water-repellents for masonry, a PROSOCO specialty, when I arrived here at PROSOCO 13 years ago in July.

These remarkable treatments seemed completely magical to me then, and still do. It’s amazing to me how these substances — many of them water-based themselves — can bar entry of liquid water into the substrate, while permitting water vapor to evaporate out.

Newbie though I was then, I could still see the advantages. Water can’t get in, to freeze and expand, and crack and spall the masonry — or to make a moist environment for mold. Moisture already in isn’t trapped within the microscopic pores and capillaries of the brick, stone or concrete — it can evaporate out.

That characteristic is often referred to as “breathability.”

My first thought was — if moisture can get out, but not in, wouldn’t the masonry eventually get so dry that it would crumble into dust? However, this dire circumstance has never come to pass. Evidently, the laws of physics don’t work that way.

The opposite problem — too much water getting into unprotected masonry does create dire circumstances.

The black gunk is mold on the (then) 100-year-old limestone of the North elevation of the Douglas County Courthouse here in Lawrence.

One of those problems is biological growth. If you think the preceding photo looks bad, you should’ve seen it in person. Eventually they cleaned the building, using PROSOCO products, natch. The cleaning contractor recommended a penetrating water repellent for the cleaned courthouse, but I don’t know if that ever got done.

North elevation, Douglas County Courthouse after cleaning, with PROSOCO products, natch. But without a water-repellent, the biological staining will come right back.

If it didn’t the biological staining will be back.

Here’s another North elevation shot. This is historic Allen Fieldhouse at the University of Kansas, getting cleaned for its 50th b-day in 2005.

Allen Fieldhouse got treated with a masonry-strengthening water repellent Weather Seal H-40, and the black gunk hasn’t returned.

North elevations are particularly susceptible because they seldom see direct sunlight. So once wet, they often stay wet, which is just how mold likes it.

Put a penetrating water repellent on that masonry, and the water can’t soak in to provide a moist environment for mold.

I poured water on this limestone sample after treating three-quarters of it with Natural Stone Treatment, a water-repellent specially made for limestone.

Here’s an example. Water beads up, unable to penetrate this limestone where I treated it with a water-repellent. Mold won’t find that a good place to thrive, because of lack of moisture. The water soaked right into the untreated edge, making it more susceptible to biological growth.

Water penetration has popped the faces off this bark-faced brick. There’s also plenty of dirt and mold.

In the photo below, water penetration has popped off the faces of the bark-faced brick in this retaining wall. The damage could have been caused by freeze-thaw cycling, or by the build-up of salts within the masonry fabric (subflorescence). Water penetration causes both problems, so either way, keeping water out of the masonry prevents the damage, as well as the mold growth.

This graphic shows how penetrating water repellents line the pores of masonry substrates with hydrophobic molecules.

Penetrating water repellents work by soaking in and lining the pores of masonry substrates with water-repellent molecules. Visualize a molecule with an umbrella on top and hooks on the bottom. The hooks chemically bond the water-repellent to the substrate. The net effect of all those little molecular umbrellas is to create a surface tension that keeps liquid out of the pores.

There’s not a thing in the world, however, to stop vapor from evaporating out, if it needs to.

Because the treatment does its job from beneath the surface, there’s seldom, if any, change to the look and feel of the masonry. That’s particularly important to restoration professionals.

They’re right to be concerned. Film-forming water-repellents, which try to protect the masonry by forming an impermeable layer over the masonry, can seriously degrade a building’s appearance.

Here’s a close-up of a failed film-forming protective treatment. The force of the moisture evaporating out caused the coating to debond.

Because they’re not “breathable,” these treatments trap moisture within the substrate until it breaks out. The results are ugly. Where the coating fails, more water gets in. Where the coating stays intact, it traps the additional moisture, so the problem gets worse and worse faster and faster.

The only solution is to remove the failed coating, and replace it with a penetrating water-repellent.

A failed film-forming coating is removed from the orange brick at the historic Folly Theater in Kansas City. Guess which side has yet to be cleaned.

That’s what happened at the historic Folly Theater in downtown Kansas City. You can read the full story here.

Water penteration into masonry and concrete causes plenty of other problems besides mold growth and surface damage. Lime run and efflorescence are two other common problems. As a matter of fact, uncontrolled water causes more damage to buildings than anything else.

Though they’re major components, water-repellents are still only one part of the system for stopping water damage. Expertise, structural integrity and a reliable, tested water repellent all work together. Still looks like magic to me, though.

One of my favorite photos. I treated this brand-new masonry With Weather Seal Siloxane PD, then hit it with the garden hose, then got the photo on a sunny summer day. Love this job!

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Abandoned hulk to smart apartments -- The 1904 Poehler Building in PROSOCO's hometown of Lawrence, Kan., is getting a new life with the help of PROSOCO products.

Visited an aging hundred-year-old hulk of a red-brick building in East Lawrence recently — 108 years old, actually, built in 1904.

The Poehler Building, a wholesale grocery distribution center for its first 50 years or so, is getting a complete restoration — using PROSOCO products, natch. In its second hundred years, it’ll be snazzy rent-controlled apartments. MCM Restoration Company, Fort Scott, Kan., is handling the masonry restoration, inside and out.

Not much is happening outside in the frigid February weather. But inside is active, and MCM Restoration Company President Craig McKenney took me: our graphic genius and photographer Stephen Falls; and our boss Marketing Director Scott Buscher into the guts of the Poehler Building for a glimpse of the restoration action. Stephen shot all these photos.

They’re looking at a grand opening in July.

One of the main jobs right now for Craig and company is getting the dilapidated white paint off the walls. Some places it’s easy and can be mechanically removed. Other places it has penetrated somewhat over the decades and has a steely grip on the brick. Grip or no, it’s got to come off. The walls will stay exposed.

Restoration techs use pressure washing and Sure Klean Heavy Duty Paint Stripper to remove the decades-old paint from the building's interior walls. Note the dam set up to catch the spent cleaner and dissoloved paint.

PROSOCO’s Sure Klean Heavy Duty Paint Stripper gets brushed on, breaks the bond, then is pressure-rinsed off. The rinse gets caught by dams of roofing roll and plastic sheeting, and is pumped into vats. There, the solids settle to the bottom. The spent cleaner and water get neutralized and pre-treated, then pumped into a truck which carts it off to our local certified wastewater treatment plant.

The solids dry out into a “cake” (yum) and go into the dumpster.

Sand blasting got an audition for paint remover of choice, but didn’t make the cut.

Here's the test panel done for the sand-blast method of paint-removal.

Same with crushed walnut shells, another abrasive blast media.

Crushed walnut shells also got a look as an abrasive blast media for paint removal, but that method wasn't chosen either.

MCM Restoration is also cutting the Poehler Building some new windows in the upper stories. On the top floor, the walls are three brick courses thick. On the first floor of the load-bearing masonry building, the walls are seven courses thick.

MCM Restoration masonry technicians salvage brick from a newly cut window in the top story of the Poehler Building.

More than a century old, these clay brick, salvaged from a newly cut window in the Poehler Building's masonry fabric, will be used again in repairs to the building exterior.

When the weather gets warmer, the building exterior will get a complete masonry restoration, Craig said, including 100 percent tuckpointing and cleaning and grafitti removal.

“After more than a hundred years, it may not look as good as when they built it,” Craig said, “but it’s going to come close — and be water-tight.”

By default, the Poehler Building will also be green, because as Washington, D.C. Architect Carl Elefante wrote in his famous “green” manifesto — “The greenest building is… one that is already built.”

Craig McKenney, President, MCM Restoration, takes a minute to smile for the camera. And all that grafitti? It's going away.

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Methodist Women's Hospital, Omaha, was cleaned inside and out by Sparklewash Construction Services, Omaha, using PROSOCO new construction cleaners. The project is a 2011 PCI co-award winner for "Best Healthcare Facility." photo courtesy Craig Christensen

Project Superintendant Jim Fleissner of MCL Construction, Omaha, Neb., admitted he was concerned.

Hardened gray concrete smeared and spattered the cream-colored precast walls of three of the entryways of the new Methodist Women’s Hospital in Omaha, the construction of which he was overseeing.

The spatters and smears landed on the walls of the entryways during installation of the concrete sub-floor. They reached about 4 feet up the walls, and had hardened and cured for two months.

Somehow, the messy splatters escaped notice until after installers laid brown and blue carpet in the entryways.

Removing jobsite staining and soiling, including excess mortar from newly constructed buildings is a routine part of construction – when it’s on the exterior. Cleaning exteriors involves hundreds, sometimes thousands of gallons of water to pre-wet the surface and then to rinse off the spent cleaner.

It’s fairly simple when you’re outside. It’s fairly simple when you remove the excess mortar before it’s had time to fully develop its hardness – 14 to 28 days.

But when the concrete is on the inside, and it has hardened like rock, and the only solution that will dissolve it may also dissolve what it’s on, and will also eat the carpet and nearby drywall, you are right to be concerned.

You can also add the customer to that list of concerns.
“Methodist Health System is one of our best clients,” Fleissner said. “But they’re very particular. It’s like they’re buying a new car. They don’t want a scratch on it.”

Fortunately, the A-team was already working on site.

“I’ve worked with Craig Christensen (SparkleWash Construction Services, Omaha) many times,” Fleissner said. “He’s knowledgeable about the surfaces that need to be cleaned and what it takes to clean them.”

Methodist Women’s Hospital was not the first hospital MCL Construction called on Christensen’s crew to clean.

Sparklewash Construction Services, Omaha, used PROSOCO products to remove hardened concrete smears and spatters from these concrete walls at Methodist Women's Hospital -- AFTER the carpet was laid. photo courtesy Craig Christensen

They’d previously worked together on Lakeside Hospital, Bergan Mercy Medical Center and Immanuel Medical Center, all in Omaha.

“So I was comfortable I had the best guy for the job,” Fleissner said.

While cleaning Methodist Women’s Hospital’s eight stories of precast concrete and inset clay masonry; its sidewalks; and even its exterior metal surfaces was routine, Christensen put his own “best guy,” Foreman Hector Hernandez, on the entryways. Hernandez has been cleaning masonry and concrete with SparkleWash Construction Services since 2001.

“The project super gave his word to the owner that this would be perfect,” Christensen said. “And I gave my word to him.”

Hernandez and his crew started by developing tactics – prime considerations being the protection of the carpet and nearby drywall from water, rinse-water and the cleaner, and protection of the precast concrete walls, while still achieving 100 percent removal of the concrete splatters.

They covered the carpet with sheet rubber. Over that went a layer of polyethylene sheeting. They taped off the drywall with blue painter’s tape.

The team brought in shop vacs to suck up pre-wetting and rinse water as soon as it came off the walls. They tested to find the highest dilution rate of the mildest cleaner that would dissolve the offending concrete, without etching or discoloring the pre-cast walls.

Confident their plans and precautions were enough to back up their pledge of perfection, Hernandez and crew went to work. First step – mechanically removing as much of the built-up concrete as they could with metal hand tools.

Even here they had to balance the force needed to detach the hardened concrete with the care needed to leave the precast unscathed, Christensen said.

Next came a thorough soaking of the walls with clean water. By filling up the microscopic pores in the precast, the “pre-wetting” keeps the cleaner on the surface where it does its job of dissolving the concrete residues left from the scraping.

Another view of one of the cleaned entryways. photo courtesy Craig Christensen

Hernandez and crew hit the gray concrete residues with Sure Klean® VanaTrol®. The specialty cleaner was developed for cleaning mortar smears off light-colored clay brick that get their color from metallic vanadium salts in the clay.

If not used with total care and attention to detail, even traditional proprietary masonry cleaners can react with the vanadium in the bricks to mobilize ugly green and brown stains.

VanaTrol® – its unique name a contraction of “vanadium” and “control” – allows for safe and quick cleaning of these sensitive masonries.

Since its introduction in 1960, contractors have found VanaTrol® to be effective for safely removing excess mortar from other surfaces requiring utmost care, such as the new limestone masonry installed at the Pentagon following 9-11.

Hernandez and crew diluted the VanaTrol® one part cleaner to three parts water, and applied it with hand pumps. They scrubbed gently, and cleaned the entire wall surface, Christensen said, for a uniform appearance.

They let the VanaTrol® dwell three to eight minutes before rinsing, Christiansen said, depending on the stubbornness of the concrete smears.
“We got about 80 percent of the residue off with the VanaTrol®,” he said.

For the rest, Christensen said, Hernandez personally spot cleaned with Sure Klean® Custom Masonry Cleaner, which is a little stronger than VanaTrol®, but made specifically for cleaning excess mortar off architectural concrete.

“Cleaning those entryways was nerve-wracking,” Christensen confessed. “We worried every minute that somehow the water was finding its way to the carpet. Thankfully, it never did.”

The exterior presented its own challenges. Along with general grit and grime from new construction darkening the precast walls, contaminants included glue and rust.

Glue smears got on the walls where inset thin bricks had fallen out and had to be glued back in place. Rain water dripping off metal exteriors put small rust stains into concrete sidewalks.

“They weren’t huge problems,” Christensen said. “But we’d promised a perfect job.”

The SparkleWash Construction Services crew restored the intended appearance of the precast exterior with Sure Klean® Light Duty Concrete Cleaner.

Light Duty Concrete Cleaner got the nod, Christensen said, because it’s safe for use around the architectural metals prominently featured in hospital’s design.

The glue came off with spot application of Sure Klean® Fast Acting Paint Stripper.

“The building looked nice before, but after Craig and his team got done, it was really something special,” Fleissner said. “It was the difference between seeing a car in a parking lot, and seeing that same car, brand new in the showroom.”

Methodist Women’s Hospital has since been named a co-winner (with St. Joseph Regional Medical Center, Mishwaka, Ind.) for Best Healthcare Facility, 2011, by PCI (Precast/Prestressed Concrete Institute).

“Our client was extremely pleased,” Fleissner said. “I was too.”

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