All About Natural Stone From The Marble Institute

Have you ever walked into a living room, a bath or a kitchen and wondered where the beautiful stone originated? Or have you ever seen the exterior of a home and wondered how that stone was produced?

Natural stones are extracted or quarried from the ground. Granite, marble, limestone, travertine, soapstone, serpentine, onyx and slate are all natural stones. The extracting from the earth and the processing of these stones to the final application on a commercial building or a residence is a long procedure.

Earth is classified geologically as a stone planet because it is entirely made of stone of various mineral compositions and forms. There are three classification of stone/rock: Igneous, sedimentary and metamorphic.

Igneous rock – are formed by the cooling of molten magma on the earth’s surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a fast rate. Extrusive igneous rocks (basalt) cool and solidify quicker than intrusiveigneous rocks (granite).

Sedimentary rocks like limestone and sandstone are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. Eroded sediments end up in the water and begin to settle (sedimentation). With time, more layers pile up and presses down the lowers layers (compaction). More strata and further compactions forces water out, while salt crystals glue the layers together (cementation).

Metamorphic rock – marble, slate & quartzite are formed from any pre-existing rock type like igneous or sedimentary, in the Earth’s crust under variable conditions of high pressures, high temperature, chemistry and time.

After learning how stone/rock is formed, one needs to find the acceptable stone for use in a building material. A sample of the stone is taken by core drilling down at least 10’-20’ for a view of the stone. If the appearance is desirable then the stone should be tested for its strength, absorption, density, and abrasion resistance. These test will help determine the applications of how this material can be physically used. You certainly don’t need to install a highly porous stone in a very wet climate or a soft material in a high traffic area to avoid abrasion of the stone.

There are several types of quarries; open pit, ledge and underground are the most common. In a ledge quarry, the stone is formed in layers where a forklift can remove the sheet of stone or cut small blocks from the hillside or mountain to remove the sheets. In an underground quarry, a tunnel is built underground in order to be able to drive into the tunnel, set up saws and pull the blocks from the wall and remove for processing. The open pit quarry is where saws cut large areas in one direction, maybe a 100’ then turn to crosscut the other direction, maybe 50’.When finished, you will have 150’to pull out of the ground.

Quarry saws are mostly used in open pits for cutting. These saws are like a chain saw with diamond segments. The saws sit on tracks that are level and straight for cutting. Each time the saw finishes a long cut and needs to be moved over or to cut in the opposite direction, the tracks have to moved as well.

The diamonds have to stay cool for the cutting so water has to flow over the segments at all times. If electricity or water is not available, then a generator is used for power and lines have to be laid to the nearest water source and pumped to the saw.

Once a large area is cut, the blocks have to be laid over and split in half. This is done using the old Roman method of feather and wedges. The feathers are placed across the block and wedges are placed in the feathers. They are either drilled with a pneumatic hammer or forced into the feather with a sledge hammer. With the force of the feather and wedges, the block with split in half. This will provide two blocks that are easier to handle. These blocks are ready to be brought above ground for inventory or for immediate processing.

Tech Talk: Anchored Stone Veneer

Anchored stone veneer is an attractive, durable exterior building envelope system and is widely used in commercial and upscale residential buildings. Natural stone units are typically of marble, granite, limestone or sandstone. Manufactured stone, also known as “cast stone”, often replicates the look of natural stones and can be a cost-effective alternate to natural stone. Regardless of the unit type, positive anchorage to the backup structure is required for anchored stone veneer. This is typically accomplished with stainless steel anchors which transmit out-of-plane forces such as wind or seismic to the backup. The vertical dead load of the anchored veneer is generally supported by a foundation ledge or shelf angle. Multi-story structures may have a shelf angle or support ledge at each floor line.

BUILDING CODE REQUIREMENTS

The 2015 International Building Code (IBC) identifies two categories of anchored stone veneer – a general class of anchored stone veneer not exceeding 10 inches in thickness and a slab-type veneer not exceeding 2 inches in thickness.

The IBC provides three prescriptive methods for the anchored veneer not exceeding 10 inches in thickness depending on whether the backup is concrete or masonry, wood stud, or steel-stud. All prescriptive methods require a cement grout at least 1 inch thick be placed between the backup and the stone veneer.

For the slab-type anchored veneer, the IBC specifies a minimum of four ties per unit with tie spacing not exceeding 24 inches. The maximum area of a unit is limited to 20 square ft. Veneer ties for slab-type veneer are required to resist, in tension or compression, two times the weight of the anchored veneer.

The IBC also references Building Code Requirements for Masonry Structures, which allows an alternate design method for anchored veneer using general principles of mechanics. This allows more flexibility to adapt the design of the veneer anchors to each unique veneer system. As you can imagine, the IBC’s prescriptive anchorage method for stones up to 10 inches thick is going to be overdesigned for typical veneers that are 2 ¼ to 4 inches in thickness.

DESIGN

The design of stone anchors is straightforward engineering. However, each component, and the connections between them, need to be evaluated for adequate strength and serviceability. For the design of the connection between the anchor and the stone, the engineer may rely on previous experience with a particular stone type or he/she may require that anchor pullout tests be performed on stone samples provided by the supplier. Anchor tests will provide a range of values for the ultimate pullout force of the particular anchor/stone combination, to which, appropriate factors of safety are then applied. In addition, ASTM C1242, Standard Guide for Selection, Design, and Installation of Dimension Stone Anchoring Systems, provides guidance on design considerations such as stress concentrations, thermal movement, stone durability and others.

INSTALLATION

On most anchored stone veneer jobs, multiple anchors are needed to accommodate variable conditions such as outside and inside corners, cavity width variations, soffits, etc. The construction documents should clearly indicate the type of anchor intended for each condition. Minor adjustments can be made in the field to cope with construction tolerances, however if conditions encountered vary significantly from the design documents, a request for information is definitely needed.

CONCLUSIONS

Anchored stone veneer is a common material for exterior building envelopes, however the anchor system that worked on the last job should not be automatically assumed to work for the next. Each anchored stone veneer system is unique in nature and should be approached as such. Budget for engineering fees to design the anchorages for each job and plan on working closely with your engineer to make sure the constructability aspects are considered as well.

The Art Behind Hardscaping and Paving

-Ralph Waldo Emerson

If you were to visit downtown Rock Hill, South Carolina, you might find yourself in the Freedom Walkway, walking on bands of red and cocoa clay pavers from Pine Hall Brick Company, laid into a running bond pattern that stops short to turn into a basket weave pattern at gathering spots.

The design is intended to get visitors to pause for a moment and consider what happened on this spot more than 50 years ago, when students from a historically black private junior college took matters in their own hands.

What happened here is best described by what you would see if you looked up. There’s a red brick wall there, emblazoned with the words, “Liberty and Justice For All.”

It’s a hardscape design that tells a story.

Standing up for a cause by sitting down

The Freedom Walkway is about the sit-in, an often-used method of civil disobedience in the Civil Rights Movement of the 1960s. Black college students adopted the method of head-on confrontations by going to segregated lunch counters and ordering food. When they were refused, they would stay seated and end up under arrest.

Bolstered by a sit-in in February 1960 by four N.C. A&T State students at the Woolworth’s in downtown Greensboro, NC, http://www.library.ncat.edu/resources/archives/four.html. There had been sit-ins in the past, but the actions by the students in Greensboro served as a springboard for other protests and brought the idea of segregation into the national consciousness. The movement spread to 250 cities across the US by the end of that month and 400 by the end of the year.

Here in Rock Hill, in January 1961, the Friendship Nine – https://en.wikipedia.org/wiki/Friendship_Nine– so named because eight of the nine were students at Friendship Junior College – integrated a whites-only lunch counter at the McCrory’s department store in Rock Hill. Like Greensboro, they added a needed boost to the movement but with a new wrinkle.

They opted to spend time in jail, rather than pay a fine that would effectively support a system that they saw as unjust. Because the sit-ins were continuing to expand throughout the South, protesters who chose to serve time saved the money that civil rights groups would otherwise have to pay for court fines – and that new strategy again invigorated the movement as it spread across the country. It was a policy that would later be adopted by the Freedom Riders, college students who traveled to the South to help blacks register to vote.

More than 50 years later, in 2015, Judge John C. Hayes III of Rock Hill overturned the convictions of the nine, saying “We cannot rewrite history but we can right history.” A prosecutor apologized to the eight men who were still living, who were in court.

Opening a book – and a new chapter

City governments, colleges and commercial real estate developers often call on hardscape design to tell a story. Before they do, it’s the job of landscape architects to research the story and come up with a design that communicates what the story is and how to best tell it, not in terms of words and pictures, but in the use of elements like clay pavers and wall art, seating and lighting and appropriate public art like sculptures or mosaics. It’s challenging for any landscape architect; more so when the architect involved is in a solo practice.

Laurel Holtzapple,a Charlotte, NC-based solo landscape architect and principal of Groundworks Studio http://groundworksstudio.com/, which oversaw the project, said she first learned about what would become Freedom Walkway through a request for qualifications from the City of Rock Hill. She assembled a team, which included Lauren Doran and Haoting Shi; then brought in Juan Logan, a painter, sculptor and expert in public art. The team was shortlisted, interviewed and then got the job.

“It really was a compressed schedule, because we had three months to do the community engagement and conceptual design,” said Holtzapple. “We began engaging with the students of Rock Hill and within community meetings, but our real focus was on civil rights arts projects.”

Some of the design came out of the community in unexpected ways. During the time that the design was being written, the 2015 court hearing – the reopening of the court docket book and the overturning of the trespassing convictions – occurred and found its way into part of the design for Freedom Walkway.

Presentations to the community and to the City Council followed. Preliminary approval was granted and bids were let for civil and structural engineering, for electrical engineering and lighting design and for general contracting. The city came back to Holtzapple to ask who would be able to execute the artistic elements – and Holtzapple recruited Carrie Gault to handle the mosaics and Sharon Dowell to paint the mural.

The biggest challenge was the relatively small size of the project itself. Freedom Walkway is 12 feet wide at its narrowest point and as it was being built, 139 Main, an apartment and retail complex, was being built immediately next to it, which meant there were two construction sites with two very different projects going on simultaneously.

Landscape architects need to be both quick and nimble, especially in such close quarters. That was proven the day that a brick tumbled off a scaffolding area and came uncomfortably close to testing the effectiveness of the hard hat that Holtzapple was wearing.

“It was all of the things that you would have in a big project, but concentrated in a tiny little space,” said Holtzapple.

The takeaways from Holtzapple’s perspective included:

• An ability to communicate. In designing a hardscape project, make sure all voices are heard, including the community and the client.
• A sense of urgency. Find the client and move quickly to get the job and carry it out.
• A knowledge of local talent. When working solo, know who else in the community that you can call on.

As it worked out, the project was carried out the way that a lot of business is done in a lot of different business categories these days: Instead of having all of the functions done by one individual, it was successfully completed by finding ways to collaborate across specialties, ensuring work for all involved.

“Gone are the days of the Renaissance man,” said Holtzapple. “It is the age of specialization. Things are so complex that it is best for you to know your area and know who works in allied professions, so you can rely on a highly qualified team to get the job done.”

How it came together

The project had its beginnings in a deteriorated former Woolworth’s building, not far from the McCrory’s where the Friendship 9 sit-in took place. The Woolworth’s was built in 1916, burned in 1934 and rebuilt in 1935. By 2014, damage to the roof had left it too dilapidated to restore. A proposal to demolish the building for a mix of retail and apartments – and a public walkway connecting a parking lot to the business district – was approved.

Holtzapple and Groundworks Studio held a number of public meetings to gather ideas for the project. As it turned out, some of the design was already there.

Once uncovered, an exterior brick wall covered with layers of paint from past advertisements provided a backdrop to the Freedom Walkway. Some – like the word “Relieves Fatigue” – were kept as a symbolic reminder of the struggles of the Civil Rights Movement.

The words “Liberty and Justice For All,” were added to the wall, from an old photograph of a protester’s sign. A chimney from the Woolworth’s building was painted dark blue, a color that has traditionally symbolized protection in the African-American community and is lighted at night, as a beacon of hope.

On the ground, curving patterns of clay pavers flow through the walkway, leading visitors on a journey. The nine cylinders of gray granite represent the stools that the Friendship 9 sat on; swirling blue spiral mosaic patterns within the field of pavers represent the turbulence of the era; the boulders within the walkway represent obstacles in the path of those seeking freedom and justice.

Even the patterns of the clay pavers themselves are symbolic: the running bond directs forward movement and directs visitors through the area, the basket weave is symbolic of the patterns of the baskets that the nearby Catawba Indians make. The craftsmanship at the site was carried out by Holtzapple and Juan Logan, artists; Carrie Gault, mosaics; and Sharon Dowell, who painted the mural.

In all, the Freedom Walkway is a work in progress, much as the Civil Rights Movement was and is. Those involved in the project say that it shows where we have been, where we are now and where we hope to be in the future.

And the meaning of this place, the reversal of an earlier conviction in light of attitudes that have changed over five decades, echoes a speech given by an unknown slave preacher, which was quoted by Rev. Martin Luther King Jr. in 1962.

King himself said the comments weren’t grammatically correct but were profound.

They were:

“Lord, we ain’t what we oughta be. We ain’t what we want to be. We ain’t what we gonna be. But, thank God, we ain’t what we was.”

The author, Walt Steele, is paver business manager for Pine Hall Brick Company, America’s largest manufacturer of genuine clay pavers. For more information, Steele can be reached at (800) 334-8689 and by email at waltsteele@pinehallbrick.com. For more information, please visit www.PineHallBrick.com

Rock Hill’s Freedom Walkway was supported by grants from the National Endowment of the Arts, the Arts Council of York County and the Barre Mitchell Community Initiatives Fund. It was awarded a 2017 ASLA Southeast Merit Design Award and a 2017 Cultural Diversity Award by the National League of Cities. Watch a video of the project’s process here: https://youtu.be/LfpcyjkNVcE

Trends in Residential Landscape Masonry through the Eyes of a Landscape Architect

Homeowners are spending more time and energy on their homes and properties than ever before. With the DIY movement on television and the big box home improvement chains, folks are showing great interest in creating and enhancing their “outdoor living areas”. In some cases, homeowners are trying to do the work themselves. However, for the work that we are typically involved in, professional stone and brick masons are employed to help construct a vision that has been created by the landscape architect or designer and the homeowner. That vision usually involves the incorporation of a variety of gathering spaces and use areas, focal points, and specialty elements to extend a homeowner’s interior to the outside spaces.

Fire pits and fireplaces have become one of the most popular improvements in recent years. Fire pits come in all shapes and sizes, from the traditional round design constructed of fieldstone with a bluestone cap, to rustic salvaged granite slabs pieced together in a square, to long rectangular fire pit kits incorporating a concrete board base structure with thin stone veneer. Homeowners need to decide if they want a wood-burning fire pit or if they would prefer a fire pit that utilizes natural or propane gas. The wood-burning fire pit is appealing to folks who enjoy building fires and who want to smell the burning wood. Gas kits are appropriate for homeowners who want to be able to enjoy a warm fire with the flip of a switch or the push of a button, as well as be able to switch it off just as easily when it is time to call it a night.

We have found that if you are looking for some real heat from your gas fire pit, it is important to use a fire pit kit that has a capacity of at least 90,000 BTUs, if not more. Pleas note that cast concrete and metal fire pits are also relatively common, but they are usually installed by landscape contractors, and not necessarily by those highly skilled in stone and brick masonry. Keep in mind that in some regions, wood burning in an open fire pit may be prohibited.

Like fire pits, outdoor fireplaces are helping folks stretch their outdoor living seasons. Outdoor fireplaces can also be designed in different sizes and with different features, and they are typically a much larger investment than that of a fire pit. When designing an outdoor fireplace, it is common for designers to incorporate a pergola or shade structure to help complete the feel of the “outdoor room”. While many fireplaces are built with CMU blocks and full 4-6” thick stone veneer, it is becoming more common for masons to build the core of a fireplace utilizing concrete panel kits, such as those by Isokern, and finish the surface with thin stone veneer.

This typically reduces the labor time. Still, fireboxes for the fireplaces are typically built with firebrick and the flue is constructed with clay elements. I think that constructing a firebox that drafts and functions successfully can be a real challenge, so we appreciate it greatly when we work with a mason who can do this well. When it comes to the appearance of an outdoor fireplace, there are a variety of materials that can be incorporated.

In New England, we tend to utilize native fieldstone for the main body of the fireplace, and then consider incorporating salvaged granite or bluestone accents for elements such as the hearth, lintel, mantle, and chimney capstones. Whether a homeowner chooses a fire pit or a fireplace, a well-designed and constructed fire feature can be key in creating an outdoor space that draws people in, and helps folks enjoy t heir property.

Outdoor kitchens are another landscape feature that has become a “must-have” by more and more homeowners. These elements are usually incorporated with a stone and/or brick terrace or wood deck. While wooden grill surrounds are not uncommon, most folks prefer to have their outdoor kitchens built with stone. As mentioned earlier with fire features, outdoor kitchens are typically constructed with a CMU core and fieldstone veneer. However, concrete board core grill surround kits are becoming more popular with masons for their ease of installation.

For countertops, granite and bluestone are still the most highly-favored materials, although concrete is increasing in popularity. Finishes can still vary for countertops, but are typically honed or thermal-treated. Sealing the countertop seasonally will help preserve the life of the countertop and minimize staining from oils and beverage spills. The days of the old thin metal kettle grill and bag of charcoal have certainly evolved.

The centerpiece of the outdoor kitchen is now the commercial grade stainless steel grill, as one would expect, which is typically either gas or propane-fueled. In recent seasons, we have had folks want us to incorporate a ceramic/kamado wood grill, in order to enjoy wood-grilled fare. Features of the outdoor kitchen go far beyond the grill, however. Gas side burners are often desired by homeowners who want to boil corn-on-the-cob, lobster, anything else that can be prepared in a pot. Warming trays and drawers are an effective way to keep food warm when cycling the different courses on and off of the grill.

Outdoor sinks have become a standard for the well-apportioned outdoor kitchen, and often paired with a cocktail center. As the social aspect has become more important in the grill area, anything related to beverages has grown also. Outdoor refrigerators and wine coolers are now becoming popular, as are icemakers, cooler bins and even “kegerators”. We always feel that a trash and recycling bin is an important element in an outdoor kitchen. The newest element on the scene is the pizza oven, which can come in various forms, from a stand-alone stainless steel unit to a traditional clay oven shell, which is veneered with stone.

Since we all know that all parties end up in the kitchen, giving the outdoor kitchen the feel of its beloved interior cousin is something that has become a common design goal. In doing that, we have found ourselves designing in “islands” with stone bases and concrete or stone table tops. In addition, stone countertop peninsulas for additional bar height seating is a way to accommodate more people in the outdoor kitchen area. Electrical outlets are designed into stone backsplashes to accommodate phone chargers, blenders, additional task lighting, as well as portable speakers.

Water elements in the garden are another area where stonemasons are practicing their craft. While this may mean a stone fountain basin to most folks, and a fountain is certainly an element that we have designed and had constructed, I am thinking more along the lines of a raised spa. While masons are typically responsible for installing the stone coping on a pool, their stonework on raised spas is more visible in the landscape, and serves not only as a functional pool, but also as a water feature and focal point. Fieldstone veneer is mortared to the exterior gunite spa walls, which are typically capped with bluestone or granite coping. The coping usually has a thermal finish on the top surface and an “eased” edge treatment on the sides.

Stone retaining walls and steps, while serving the purpose of retaining grade and providing access from one space to another, are also being designed and constructed as aesthetic elements. Stonewalls have long been desired as garden elements, and can vary in appearance from loose, dry-laid farmer-type walls to tightly-fitted architectural-type landscape walls. Salvaged granite accents are often incorporated to add interest and give the wall a more aged appearance. Steps may be constructed of fieldstone risers with bluestone tread, full-depth bluestone, as well as salvaged granite slabs. We have even designed lawn steps stone risers for an even more unique garden experience. A stone “moon gate” is an intriguing focal point in a garden path that we recently designed and had constructed.

In residential gardens, landscape architects and masons are collaborating to create features that enable and inspire homeowners to experience their property more deeply, to spend more time outside in the “shoulder” seasons, and to socialize with friends and family. This collaboration is one that can result in timeless beauty and increased enjoyment in the landscape.

MASONRY Publications Partners With American Institute of Architecture Students

MASONRY Publications has announced a partnership with the American Institute of Architecture Students. This partnership will further expand MASONRY Publications’ reach within the educational community while also highlighting the important work that AIAS’ university partners and student members are doing to define the next generation of architecture.

“Working on this partnership, in particular, has been a highlight of my career. This relationship is designed to help feature the schools, projects, and people who are the future of the industry. It’s one of our primary missions at the magazines, and we are honored to call AIAS our partner,” said Dan Kamys, Editorial Director of MASONRY Publications.

The new content and expanded distribution to AIAS members at no charge will begin with the November 2018 issue of MASONRY DESIGN. Additional feature articles will come in the form of school profiles, project case studies, and interviews with AIAS members and former members making a difference in the community. MASONRY Publications will also contribute to the AIAS CRIT Journal and collaborate with the editorial team on a variety of topics.

“An understanding of today’s materials and what they can accomplish in design represents a critical tool that architecture students need for success. Partnering with MASONRY Publications is a fantastic new addition in our expanded effort to ensure our members get exposed to information and skillsets beyond what they’re learning in the classroom,” said AIAS Executive Director Nick Serfass, FAIA, CAE.

ABOUT MASONRY PUBLICATIONS— Comprised of MASONRY and MASONRY DESIGN, MASONRY Publications are the Mason Contractor Association of America’s magazines aimed to inform the entire construction process. Since 1961, MASONRY has served as the premier resource for mason contractors to stay up to date on the industry. Since 2008, MASONRY DESIGN has served as a cornerstone within the architectural, design, and educational communities.

ABOUT AIAS — The American Institute of Architecture Students is a non-profit, student-run organization dedicated to programs, information and resources on issues critical to architecture and the experience of education.

ABOUT MASON CONTRACTORS ASSOCIATION OF AMERICA — The Mason Contractors Association of America (MCAA) is the national trade association representing mason contractors. The MCAA is committed to preserving and promoting the masonry industry by providing continuing education, advocating fair codes and standards, fostering a safe work environment, recruiting future manpower, and marketing the benefits of masonry materials.

Source: masonrymagazine