Archive for December, 2011

This partially cleaned brick and block wall shows the difference proper new construction cleaning can make. This masonry was cleaned with Sure Klean 600.

I saw an ad the other day by another manufacturer of new masonry construction cleaners. These specialized cleaners are used for the final cleandown of newly constructed masonry buildings.

Final cleandown is important, as you can see from the photo. It rids the wall of mortar smears and clarifies the mortar joints. Though it’s one of the least expensive parts of construction, final cleandown is crucially important to the building’s final appearance.

The ad contended that the product it promoted was all that you need to clean any type of new masonry – burnished concrete block to clay brick – one size fits all.

At PROSOCO, we recommend — and make — specific cleaners for nearly every type of masonry on the market – burnished concrete block to clay brick – the right tool for the right job.

Who’s right?

As a PROSOCO employee, you might expect me to be biased toward my company, and so I am — a little. But as a writer on construction issues, I have to be honest.

The fact is, IF you can get to the masonry cleaning soon enough — within seven to 10 days of the masonry going up, before the excess mortar has had a chance to really harden, just about any masonry cleaner will do the trick.

And in any masonry cleaning job, you always want to use the gentlest cleaner possible especially with your more acid-sensitive masonries, like concrete brick or artificial stone. And you will want to clean early as possible. Not before seven days though — earlier than that and you risk damaging the mortar joints, which are still setting.

After 10 days, or so, the mortar will be harder and will need a tougher cleaner to break its grip on the masonry. So PROSOCO looked at the different types of masonry, and tested them to see what they could withstand.

Then we made cleaners that were tough enough to get the hardened mortar off, but without damaging the specific types of masonry. Because masonry varies so much, the cleaners also had to vary.

For instance, red clay brick is acid-insoluble. So we recommend our strongest cleaner for that — Sure Klean 600. On the other hand, many light-colored bricks take their distinctive appearance from the addition of vanadium — a metallic salt — within the clay.

Of course we all know what happens when acid meets metal; big trouble. And so the acid content for vanadium-containing bricks — most light colored bricks — must be specially harnessed and buffered.

The wrong kind of cleaner reacted with the vanadium salts in this masonry to mobilize these ugly stains. There are specialty cleaners to repair this damage, but it isn't cheap. Sure Klean VanaTrol was designed to prevent this kind of damage.

The result — Sure Klean VanaTrol (Vanadium + Control).

IF you are really careful, and IF you do plenty of testing, and IF you have decades of experience with masonry cleaning — you MIGHT be able to get away with using a masonry cleaner on a substrate for which it isn’t intended.

But in most cases, your results will vary — from not getting the best results, at a minimum; to inflicting expensive damage on the masonry.

The point behind making precision cleaners for specific masonries is to eliminate that unpredictability. With today’s construction schedules, there’s barely time to do it at all, let alone to do it again.

When you use a cleaner that’s made for the specific masonry you need to clean, you’re already starting with a significant safety factor. And with the relatively unskilled labor that often does the cleaning — you NEED all the safety factors you can get!

It’s a fact — different masonries have different characteristics. There is no one cleaner suitable for all of them under most circumstances.

Whatever cleaner you use, though, you should always protect yourself by testing before you clean. Try the cleaner on an out-of-the-way area under the same conditions you plan to clean under — including dilution-rate.

You may have to do some adjusting of dilution-rates and dwell times, but in the end, you’ll have a beautiful, successfully cleaned building.

Short answer: In masonry cleaning, one size doesn’t fit all, and never has. And always test before you clean.

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The polished concrete entryway floor at Tse’bii’nidzisgai Elementary School (pronounced Suh-Bee-Niz-Iz-Guy) features a Navajo wedding basket design. The design is rich with meaning for the initiated. Scot Zimmerman photo

It’s a marriage of practical and esoteric, written in concrete at a remote Navajo elementary school set among the towering red buttes and mesas of America’s fabled Monument Valley, Utah.

When you stand on the polished concrete of Tse’bii’nidzisgai Elementary School’s main entryway, you stand upon an iconic design central to Navajo life and understanding of the world.

The school’s name is pronounced “Suh-Bee-Niz-Iz-Guy,” says Project Architect Brian Parker, MHTN Architects, Salt Lake City. Parker worked closely with tribal leaders and teachers to first learn, and then incorporate Navajo culture into the school’s design.

“That experience was one of the greatest moments of my career,” he said.

The pattern in the approximately 1,000 square-foot entryway is taken from the traditional Navajo wedding basket design. Its central spot represents Mother Earth and the beginning of the world. The dark rays spreading out show the journey of life through clouds and mountains.

The red band is said to symbolize the sun, or rainbow, according to Utah’s State Historical Society.

The polished concrete floor in the school’s cafeteria/multi-purpose room features a design drawn from classic Navajo blankets. It was suggested by students, Parker said.

This floor plan for the Tse’bii’nidzisgai Elementary School (pronounced “Suh-Bee-Niz-Iz-Guy”) shows the location and approximate colors of the polished concrete floors throughout the school. Copyright MHTN Architects

The round entryway structure is reminiscent of the traditional Navajo Hogan. Clerestory windows and a generous skylight keep the space alive with natural light, and the polished concrete gleaming.
The client, Utah’s San Juan School District, chose polished concrete as the medium for rendering the design, as well as for the rest of the school.

“They wanted something practical and durable,” Parker said. “Those floors have to stand up to hundreds of kids, year after year.”

Tse’bii’nidzisgai Elementary School is the district’s first experience with concrete floors. “It’s a bit of an experiment,” Parker said. “Though you pay a little extra for polished concrete installation compared to other flooring choices like VCT, if you do it right, you save money on life cycle costs.”

This photo shows the Consolideck® GemTone Stain wedding basket design in progress on the entryway polished concrete floor at Tse’bii’nidzisgai Elementary School (pronounced “Suh-Bee-Niz-Iz-Guy”). photo courtesy Hogan Construction & Associates

The savings stem from not having to repeatedly scrub, strip, wax or replace worn topping surfaces, Parker explained. He said the district plans to monitor the floors’ performance and cost-savings over the next three years.

Initial reports are good, he said. The floors have already proven to be lower maintenance than other flooring choices.

“The custodians seem to love the floors,” he said.

Work began as Bryan Borcher, Intermountain Concrete Polishing, Meridian, Idaho, brought his 900-pound grinders to flatten and prep the floor for polishing. The massive machines took the floors from a steel-troweled finish to the edge of polish with a succession of ever finer-grit pads.

Hogan Construction & Associates, Salt Lake City, the project G.C., used their own smaller machines for the final polishing from a 400-grit finish to a glossy 800-grit, said Project Manager J.D. Forbush.

Along the way, the installers hardened and densified the approximately 52,000 square feet of concrete floor with Consolideck® LS® lithium-silicate hardener/densifier.

After grinding, the LS® prepped the floors for polishing by filling microscopic concrete pores with tough calcium silicate hydrate – the same hard substance that makes concrete hard to begin with. Less porosity means the surface polishes faster and more effectively.

It also means the finished floor has greater stain- and abrasion-resistance than untreated concrete.
They decorated the polished concrete with water-based Consolideck® GemTone stains, in colors Desert Sand, Georgia Clay and Espresso.

The Hogan Construction crew then applied a micro-thin layer of Consolideck® LSGuard®. The protective treatment, burnished on at 3,000 rpm, liquefies and melds with the concrete for additional stain-resistance and gloss that never needs to be replaced.

Alberto Flores, a 20-year master concrete finisher with Hogan Construction & Associates spreads a thin coating of Consolideck® LSGuard® on the polished concrete of the cafeteria/multi-purpose room floor at Tse’bii’nidzisgai Elementary School (pronounced “Suh-Bee-Niz-Iz-Guy”) just before high-speed burnishing. photo courtesy Hogan Construction & Associates

LSGuard® contains lithium silicate for a further hardening/densifying effect, which is why it bears the “LS®” prefix.

“We chose Consolideck® products because they’ve worked well on our other projects,” Forbush said. “And they have good field support.”

They needed field support on this project, Forbush said. Though decorating the interior floors went smoothly, the brutal July heat and wind made coloring about 25,000 square feet of exterior concrete recreation area difficult.

Forbush’s crew decorated the exterior concrete with Consolideck® ColorHard. ColorHard is a mix of colorant and LS®. After stirring a packet ColorHard dye into a bucket of LS®, you simply spray and spread the mixture onto the concrete.

You get hardening, densifying and decoration all in one simple step.

The problem was that the bone-dry concrete almost instantly sucked down the mixture’s water component, while heat and wind quickly dried the colored hardener/densifier on the surface, before it could penetrate. Even though the crews applied the ColorHard between 5 and 6 am, before the heated winds really kicked up, they still had trouble with warmth and excessive dryness.

Students play on the “Color Wave” at Tse’bii’nidzisgai Elementary School (pronounced “Suh-Bee-Niz-Iz-Guy”), Monument Valley, Utah. The wave is meant to represent a flow of water to and from the building. Scot Zimmerman photo

“The local PROSOCO sales manager, Bruce Ferrell, showed us what do,” Forbush said. “He was pretty good.”

Forbush explained that Ferrell had the crew change out LS® for LS/CS® in the ColorHard mix. LS/CS® penetrates more quickly because it’s a thinner fomulation, Ferrell told the crew.

He also had them boost the water content of the mix, though he recommended using pure water to do that. Tap water may contain chemicals and minerals that can affect the densifier. Construction-site water is often really bad, Ferrell says, since it’s usually full of rust, minerals, sediment, and other potential contaminants.

With those adjustments made, the ColorHard went down fine, Forbush said.

Application of water-based Consolideck® SLX100® Water & Stain Repellent locked the color into the outside concrete against summer monsoon rains, soft-drink spills and other agents of destruction.

On the inside, the one thing you really have to be careful of is protecting the finished floors from other trades during construction, said Colby Davis, the school district’s director of buildings and grounds. He explained that even though the floors are durable concrete, their appearance can be marred by heavy construction traffic and materials.

“In the end it turned out fine,” he said. “We even saved money with the LSGuard®. It made our 800-grit finish look shiny as a 1200-grit finish, without the extra labor cost. It adds some protection, too.”

“People love these floors,” Davis said. “They love the colors, the patterns, the natural looks. These floors bring the natural beauty of our Monument Valley location into the building.”

The design of MHTN Architects' Tse’bii’nidzisgai Elementary School, both inside and out, draws much of its inspiration from Navajo lands and culture. Scot Zimmerman photo

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A mason installs brick over a structural wall coated with a fluid-applied air & water barrier. Mason contractors are increasingly taking on installation of the air barrier.

I’m working on a story for Masonry Magazine about how mason contractors can profit from the new breed of fluid-applied air barriers now on the market.

I’ve interviewed two contractors so far, and both say the same thing.

It’s WAY worth it for contractors to “self-perform” air barrier installation because it just about always costs less than subbing it out. It also gives the mason contractor more control at the job site. Obviously, a sub who gets delayed installing the air barrier also delays the masonry installation.

Ed Purdy, Vice President and Co-Owner of Purdy Masonry, Zionsville, Ind., said his company has been installing air barriers for about five years.

“We usually had to supply the scaffolding and other equipment anyway,” Ed said, “so why not do it ourselves?”

Brad Dennis, Ziolkowski Masonry, South Bend, Ind., said his firm also began installing air barriers about five years ago, and for the same reasons Ed cited — cost and control.

He says the “new breed” of easy-application, sprayable, water-based air and water barriers make it easy.

“We won’t get involved with air barrier installation when fabric wraps or peel and sticks are specified,” Brad said. “That level of difficulty and complexity isn’t worth our time. We’ll sub those out.”

Ease of installation isn’t the only factor Brad looks at in deciding whether to take on air barrier installation. He says the specified air barrier must be readily available and have first-class manufacturer back-up, including formal hands-on training in the products and no-cost job-site and telephone technical assistance.

“Our first job was about five years ago. We applied a sprayable product to block back-up at the riding stables at Culver Military Academy in Northwestern Indiana,” Brad said. The building had a brick veneer with a stone base.

“The air barrier installation went smoothly. That was due in large part to the training our guys got from the manufacturer beforehand,” he said.

Though product data sheets and instructions are usually comprehensive and informative, there’s no substitute for hands-on training, especially when you’re doing it for the first time. Even the best product literature won’t help you understand how important it is to connect your air barrier to the roof and to the slab or below-grade waterproofing.

The printed page can’t give you the “feel” of how to correctly spread or tool the material. You can only get that by trial-and-error experience — or through training and practice.

“We’ve done about 50 air and water barrier installations since that first job,” Brad said. “If we can do them, we will do them.”

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