Tag Archives: stone

Building Stone Institute announces award-winners

15CentralParkWest_RAMSA

New York City’s 15 Central Park West echoes the grand apartment houses of the 1920s. Its limestone façade was cut from the same quarry that produced stone for the Empire State Building. “It’s a particular honor RAMSA selected Indiana limestone,” said Tom Quigley, CEO of Indiana Limestone Co. “This design choice identifies the building with a rich architectural tradition in New York and around the nation. Needless to say, it also imparts a beauty and permanence all its own.” Photo © Peter Aaron, OTTO

The Building Stone Institute (BSI) has named a dozen outstanding projects at its biennial Tucker Design Awards.

First presented in 1977, the program honours the work of both the building and landscape design communities; they are presented to those projects exhibiting excellence and innovation in concept, construction, and use of natural stone. This year’s winners are:
● Noble and Greenough School’s castle project (Dedham, Massachusetts) by Architerra in association with Towers | Golde;
● Schermerhorn Symphony Center (Nashville, Tennessee) by David M. Schwarz Architects;
● George “Doc” Cavalliere Park (Scottsdale, Arizona) by Floor Associates (JJR | Floor) in association with Weddle Gilmore;
● Bass Library at Yale University (New Haven Connecticut) by HBRA Architects;
● U.S. Federal Building & Courthouse (Tuscaloosa, Alabama) by HBRA Architects;
● Lakewood Cemetery Garden Mausoleum (Minneapolis, Minnesota) by HGA;
● New Country House (Villanova, Pennsylvania) by John Milner Architects;
● Franklin D. Roosevelt Four Freedoms Park (New York City) in honor of Louis I. Kahn, FAIA, with Mitchell | Giurgola Architects;
● Casa de las Lomas (Austin, Texas) by Michael G. Imber Architects;
● Escondido (Horseshoe Bay, Texas) by Michael G. Imber Architects;
● Fifteen Central Park West (New York City) by Robert A.M. Stern Architects (RAMSA); and
● The Barnes Foundation (Philadelphia, Pennsylvania) by Tod Williams Billie Tsien Architects.

For more on the winners, visit BSI’s project gallery.

In conjunction with the Tucker Design Awards, BSI recognized Peter Walker, FASLA, as its 2014 Bybee Prize winner. Given in honor of the late James Daniel Bybee, a respected and long-standing member of the Building Stone Institute, the accolade is awarded to an individual architect or landscape architect for a body of work executed over time.

Specifying Stone Design: New technologies increase opportunities

Photos © Steve Maylone

Photos © Steve Maylone

by Tim Feldhege, Amy Thielen, and Kathy Spanier

Ensuring the vision outlined in architectural renderings translates to building material manufacturing, and then construction, requires careful attention to design and technical detail. Stone manufacturers are increasingly using new technologies to help make sure details are translated to the final outcome.

For example, when a project’s scope incorporates transportation of granite benches at different times without damage, detailing is essential. In these situations, the use of 3D scanning and modeling ensures the design and construction team see how the pieces fit together. Such technologies, as well as various computer-aided design and drafting (CADD) and building information modeling (BIM) software, also prove beneficial for restoration and replication projects.

Technology provides details
In the fast-paced construction industry, great attention to detail is required to ensure everything comes together as the architect or designer envisions the project. Companies that are both the supplier and manufacturer of natural stone have the opportunity to help all parties by providing accurate and complete details. With 3D scanning, BIM, and CADD software, the design cycle is shortened, and the possibility for confusion or misinterpretation is minimized.

The Ralph L. Carr Colorado Judicial Center in Denver encompasses courthouses for the Colorado Court of Appeals and Supreme Court, as well as a 12-story office building for support functions associated with the courts.

The Ralph L. Carr Colorado Judicial Center in Denver encompasses courthouses for the Colorado Court of Appeals and Supreme Court, as well as a 12-story office building for support functions associated with the courts.

Further, 3D scanning and modeling assist the detailing process by providing a level of information once impossible. Acute manufacturers use 3D scanning on numerous projects, from detailed scale clay, plastic, and wood, to full-size working models. By scanning the design and inputting this information into modeling software, the manufacturer can recreate the exact design intent of the artist or architect. The manufacturer can then easily convert this information into a 2D drawing or computer-aided manufacturing (CAM) software to send it to a five-axis or computer-numeric control (CNC) machine to create a finished product.

CADD and BIM prove especially important for restoration and replication projects. When a project involves working with existing structures or reproducing numerous similar elements, details become critically important. Any slight degree of miscalculation could mean significant setbacks for the project team.

Scanning services around the country will make 3D scans of anything from small individual pieces of the application to the entire building. From that scan, the manufacturer can re-create a BIM model and/or 2D drawing from which to work. The software also helps the design and construction team review integrated models and data with stakeholders to gain better control over project outcomes. Integration, analysis, and communication tools help teams coordinate details, resolve conflicts, and plan projects before renovation begins.

To help ensure success, the supplier should be able to provide a quality 3D model and accurate 2D drawings. Design teams should communicate expectations to all parties, hold weekly progress meetings, and monitor the model’s progress.

Ralph L. Carr Colorado Judicial Center
Located in Denver, the Ralph L. Carr Colorado Judicial Center demonstrates successful use of modeling software. Adjacent to the State Capitol building, the 64,638-m2 (695,767-sf), $258-million center encompasses courthouses for the Colorado Court of Appeals and Supreme Court, as well as a 12-story office building for support functions associated with the courts.1

A building material supplier able to quarry and fabricate granite in large-scale quantities provided 10,003 m2 (107,677 sf) of gray and white granite for the buildings and 2242 m2 (24,138 sf) of green granite for the hardscapes.

Key to the project’s success was the collaboration and use of BIM across the design and construction team, including key suppliers. With BIM, digital 3D representations of a facility’s physical and functional characteristics are shared and managed among team members through the project’s lifecycle.

“The nearly universal adoption of BIM by members of the design and construction team helped make this project seamless,” said Martin Eiss, the project designer and a senior associate with Fentress Architects of Denver.

With BIM, the team saved significant amounts of time. Parts and pieces on the stone applications were modeled early in the design phase with the architectural team. In the field, general contractor Mortenson Construction of Minneapolis used BIM, which facilitated coordination and helped address potential conflicts before they arose. The judicial center opened two months ahead of schedule, thanks in large part to the team’s coordination and adoption of BIM.

Designed with a 100-year-plus lifespan, the completed building speaks to the future in terms of courtroom design and technology, with the flexibility to accommodate future needs. The courthouse is designed to add an additional courtroom within the existing space. Also, various technologies will be able to accommodate future closed-circuit television broadcasts, as well as additional wireless technology.

Low-maintenance, long-lasting materials such as granite were specified for their durability. Natural stone was used in all public area floors and full height on the walls in the high-traffic first floor and lobby areas.

“This project demonstrates the more we can integrate BIM early on, the more successful a project can be,” said Eiss “The relationship with the subcontractors and suppliers was critical—all were engaged in the design phase, which proved essential to this project’s success.”

The judicial center opened two months ahead of schedule, thanks in large part to the project team’s coordination and adoption of building information modeling (BIM).

The judicial center opened two months ahead of schedule, thanks in large part to the project team’s coordination and adoption of building information modeling (BIM).

More than 12,000 m2 (130,000 sf) of granite was used to construct the Colorado Judicial Center.

More than 12,000 m2 (130,000 sf) of granite was used to construct the Colorado Judicial Center.

 

 

 

 

 

 

 

 


Advances in sandblast technology

Beyond modeling software, the stone industry has achieved great progress in its manufacturing and production technology. A great example is in the technique of sandblasting. In the past, sandblasting natural stone was confined to a few, specific design elements. Today, advances in sandblasting and carving technology allow skilled stone manufacturers to create art in natural stone that would have been thought impossible only decades ago. However, the relationship with the stone manufacturer is critical to a successful installation featuring graphical design elements using sandblast. The right stone manufacturer will enhance the project’s outcome through quality workmanship and a consultative approach through every project phase.

What should be considered?
Photographs and other images can be transferred to natural stone with realistic detailing, using sandblasting and carving techniques. Lettering can be carved and enhanced with a color element; the precise replication of ornate elements such as column caps can be created.

Skilled and knowledgeable stone providers will work with the entire team to bring these artistic visions to reality. While cost is always an important consideration, many other factors must be taken into account for a successful outcome.

Will the manufacturer assist in the project’s consulting and sampling phases?
In the consulting phase, design experts from the manufacturer can provide samples and offer advice to guide the team through the process. At the beginning of the project, a stone manufacturer can provide samples to help visualize the design intent. Providing samples before the order is placed will also allow the team to see the provider’s workmanship and capabilities. After the order is placed, sampling helps to refine final details and bring the design to reality.

Does the manufacturer invest in new technology?
Technology offers numerous capabilities to achieve the design intent. For example, AutoCAD and 3D modeling software allow computer-generated transfer of images and precision. Other technologies include CNC laser-etching, and stencil and film technology. With these capabilities, manufacturers can transfer nearly anything from hand sketches to photos onto the stone’s surface.

Does the manufacturer offer the capability to add hand-craftsmanship when needed?
A skilled craftsperson can give an image depth or bring a truly artistic touch to the project. Manufacturers that can offer both craftsmanship and technology will be best able to meet the project’s needs. The following project examples demonstrate various artistic elements achieved with sandblasting techniques.

The Wall of Remembrance at Eagle Circle honors tribal culture and is constructed in a semi-circular shape, in the image of an eagle.  [CREDIT] Photos courtesy of Coldspring

The Wall of Remembrance at Eagle Circle honors tribal culture and is constructed in a semi-circular shape, in the image of an eagle. Photos courtesy of Coldspring

The eagle’s eye at the Wall of Remembrance at Eagle Circle shows an example of the intricate work possible on granite through new technologies.

The eagle’s eye at the Wall of Remembrance at Eagle Circle shows an example of the intricate work possible on granite through new technologies.

 

 

 

 

 

 

 

 


Wall of Remembrance at Eagle Circle

For many projects, more than one sandblast technique is used to achieve the desired result. Perhaps one of the best examples demonstrating the use of various sandblasting techniques in recent years is the Warrior/Veterans Wall of Remembrance at Eagle Circle in Hannah, Montana. Here, the Confederated Salish and Kootenai Tribes of the Flathead Nation commissioned renowned artist and tribal member, Corwin ‘Corky’ Clairmont, to design a tribute to the men and women who lost their lives in service to the United States.

The project began with Clairmont’s hand drawings. The granite provider rendered the drawings onto the material using various techniques such as sandblasting. Intricate and symbolic, Clairmont’s sketches required exacting replication to faithfully render the story in stone. A series of shadowing and colors were fabricated, eventually transferring the drawings onto a black granite, which was specified for its color and texture.

Honoring tribal history and culture, the finished granite wall stands approximately 3 m (10 ft) tall at its highest point; it is constructed in a semi-circular shape, in the image of an eagle. In all, the memorial consists of 21 stone panels, varying in height, from 1 to 3 m (3.5 to 10 ft).

To accentuate sandblasting, other graphical elements were added via hand-carving, sculpting, and etching. Working with a manufacturer that can provide a wide spectrum of services helps ensure the artistic intent is accurately captured.

The Cedar Park Veterans Memorial features a black granite obelisk—a 3.6-m (12-ft) diameter, gray granite base of 1.8-m (6-ft) tall panels.

The Cedar Park Veterans Memorial features a black granite obelisk—a 3.6-m (12-ft) diameter, gray granite base of 1.8-m (6-ft) tall panels.

Cedar Park Veterans Memorial
Located in the Cedar Park suburb of Austin, Texas, the Cedar Park Veterans Memorial demonstrates technology’s use for transferring images onto stone. One of the memorial’s design elements is a black granite obelisk sitting atop a 3.6-m (12-ft) diameter, gray granite base of 1.8-m (6-ft) tall panels. Each panel honors a different branch of the U.S. military through highlighted etchings displayed on black granite.

Advanced technology transferred photographs depicting the Army, Navy, Air Force, Marines, Merchant Marines, and Coast Guard onto the stone panels. Each image needed to maintain a realistic, photo-like appearance. As such, the selection of black granite was particularly important to capture details.

Stone industry standard
Natural stone’s green benefits are often a key factor in its specification in today’s increasingly sustainability-conscious building industry. Formed by nature itself, natural stone has an enduring lifecycle, and can often be locally sourced, depending on project location.

The Natural Stone Council (NSC) is a collaboration of natural stone trade associations and businesses. In collaboration with NSF International, the council has developed an American National Standard for the sustainable development aspects of dimensional stone production. Known as NSC 373, Natural Dimension Stone Standard, it is currently in review, with finalization planned for later this year.

NSC 373 will help project teams and consumers determine whether a dimensional stone product has been extracted and manufactured in an environmentally preferable manner. The standard defines Environmentally Preferable Manufacturing Practices (EPMPs) for the quarrying and manufacturing of dimensional stone. Criteria that consider the social, environmental, and human health impacts associated with the dimensional, natural stone product lifecycle will be outlined by the standard.

Industry response
In advance of the NSC standard, some natural stone quarries and manufacturers have already set internal standards and best practices to help reduce their environmental footprints. For example, practices can be made more sustainable by:

  • recycling industrial water;
  • quarrying stone on demand;
  • using diamond saws;
  • reducing use of explosives to minimize waste; and
  • optimizing energy-efficient strategies throughout operations.

Additionally, the Declare Product Database, developed by the International Living Future Institute (ILFI), was created to make it easier for project teams to identify products compliant with the Living Building Challenge performance standard. The ‘Red List’ identifies the worst-in-class materials, chemicals, and elements known to pose serious risks to human health and the greater ecosystem. Any project seeking certification under the Living Building Challenge must be free of Red List chemicals and materials.2

Some materials used during installation of traditional stone construction, such as curtain sealers or adhesives, may fall under the Red List. Typically, the stone manufacturer would not apply any sealants or adhesives on the stone before sending it to the job site.

Further, detailed information about the environmental profiles of natural stone products, and their impacts over the entire lifecycle, is available through the NSC Life Cycle Inventory datasets and fact sheets on natural stones.3

An upcoming stone industry standard, Natural Stone Council (NSC) 373, Natural Dimension Stone Standard, will help project teams and consumers determine whether a dimensional stone product has been extracted and manufactured in an environmentally preferable manner.

An upcoming stone industry standard, Natural Stone Council (NSC) 373, Natural Dimension Stone Standard, will help project teams and consumers determine whether a dimensional stone product has been extracted and manufactured in an environmentally preferable manner.

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Conclusion
Stone—a natural, durable, recyclable, and reusable material—is a suitable choice for projects where sustainability is an important consideration. For a truly green project, the material must be evaluated in terms of its complete lifecycle, from quarrying and fabrication to transporting and installation.

Notes
1 For more on this project, see the article “Reinventing Conventional Curtain Walls,” by Christopher O’Hara, PE, SECB, and Julian Lineham, PE, C.Eng., MICE, SECB in the April 2013 issue. (back to top)
2 The Declare Product Database is available at www.declareproducts.com/product-database. (back to top)
3 Visit the NSC at www.genuinestone.com. Select the Stone & Sustainability section for access to the NSC Life Cycle Inventory. (back to top)

Tim Feldhege has worked at Coldspring for 35 years and is now director of sales. He is responsible for managing drafting, sampling, and stock utilization initiatives and has been instrumental in the company’s development and execution of building information modeling (BIM). Feldhege can be reached at tfeldhege@coldspringusa.com.

Amy Thielen, Coldspring’s director of sales, has been with the company for 14 years. She is an expert in fabrication, quarrying, construction channels, and software associated with the stone manufacturer. Thielen represents the company on the Landscape Architects Foundation (LAF) and American Society of Landscape Architects (ASLA) Minnesota Chapter. She can be contacted by e-mail at athielen@coldspringusa.com.

Kathy Spanier is the marketing director at Coldspring. She was part of the Natural Stone Council’s (NSC’s) Sustainability Committee creation, participates in the NSC373 Stone Certification initiative, and is a current member of Building Stone Institute’s (BSI’s) Board of Directors. Spanier can be reached at kspanier@coldspringusa.com.

Specifying Movement Joints and Sealants for Tile and Stone: Reviewing current industry standards and design options

Photo courtesy Florida Tile

Photo courtesy Florida Tile

by Donato Pompo, CTC, CSI, CDT, MBA

In one way or another, all tile and stone assemblies move. Whether due to thermal or moisture movement, shrinkage, freezing, or dynamic structural movements, tile and stone installations are subjected to them all. To ensure a long-lasting installation, architects must specify the requirements for movement joint design and placement, along with the correct type of sealant for filling those joints.

A ‘movement joint’ is a general term used for all types of joints seen in construction materials that control and allow movement. Most commonly, they are known as ‘expansion’ or ‘control’ joints, but there are various categories. Generally, they contain an appropriate pliable sealant for the intended application, which is often referred to as a ‘soft’ joint.

Movement joints allow for the material in which they are placed to move without restraint; they control where the movement manifests to avoid random cracking in finish materials. An example would be the joints or separations in a concrete sidewalk. If there were no movement joints in the concrete sidewalk, then it would crack at a random point as it is subjected to shrinkage during curing, or to expansion when it is exposed to moisture (and then contraction again as it dries). Rising temperatures cause expansion, lowering temperatures cause contraction, and wet freezing conditions cause both, as the temperature drops and the moisture freezes.

There are other types of structural movement from the ground or its foundation that can cause various kinds of movement in the form of deflection. These stresses, and the resulting deformations, are compounded by adjacent materials that have a different coefficient of movement properties—the differentials can lead to serious problems, particularly over time as the respective materials go through various degrees and combinations of cycles from wet to dry or hot to cold, and so forth. Movement joints are also designed to isolate different materials from each other so they do not affect adjacent materials.

More often than not, when there is a tile (e.g. ceramic, porcelain, stone, or glass) failure a contributing factor is the lack of properly installed movement joints. In some cases the failure could have been avoided, or damage limited, if there had been properly installed movement joints. Just like concrete sidewalks, slabs, and bridges, tile and stone need to have movement joints to control the anticipated movements within a structure and the various climatic conditions it will be subjected to throughout the years.

Small horizontal movements can result in exponentially larger vertical movements. When one end of a ruler is restrained and the other end moved toward the center 3.2 mm (1/8 in.), there is a 51-mm (2-in.) rise at its apex. Photos courtesy Ceramic Tile and Stone Consultants

Small horizontal movements can result in exponentially larger vertical movements. When one end of a ruler is restrained and the other end moved toward the center 3.2 mm (1/8 in.), there is a 51-mm (2-in.) rise at its apex. Photos courtesy Ceramic Tile and Stone Consultants

Figure1b

Troubles with tile and stone
This author has seen tile floors that did not have adequate movement joints—where a portion of the floor was tented (i.e. debonded and raised) several inches off its substrate during the heat of the day, but was lying flat at night when it cooled down. For a good example of how small horizontal movements can result in exponentially larger vertical movements, one can take a 1219-mm (48-in.) metal ruler and lay it on a horizontal surface. When one end of the ruler is restrained and the other end moved toward the center 3.2 mm (1/8 in.), there is a 51-mm (2-in.) rise at its apex. In effect, this is what happens to tile floors when they tent. They are constrained at their perimeters with no movement relief, the tile is typically insufficiently bonded, and it expands for one reason or another.

Well-bonded tile floors tend to crack to relieve the stress rather than lose their hold. Properly placed movement joints allow the tile to move and control where the movement manifests (i.e. within the joint where the tile is not restrained).

Tile and stone installers may have practiced their trade and honed their skills, but they are not engineers. In other words, while installers have some responsibility in ensuring movement joints are included in the tilework, it is ultimately up to the architect to specify the appropriate design, materials, and locations.

The Tile Council of North America (TCNA) provides general movement joint guidelines for tile and stone applications in its TCNA Handbook for Ceramic, Glass, and Stone Tile Installation, listed under Detail EJ171, “Movement Joint Guidelines for Ceramic, Glass, and Stone.” TCNA states:

because of the limitless conditions and structural systems on which tile can be installed, the architect or designer shall show the specific locations and details of movement joints on project drawings.

There are industry standards that help design the appropriate movement joint layout and design for the intended application:

  • ASTM C1193, Standard Guide for the Use of Joint Sealants, which provides guidelines on how to use and install sealant joints; and
  • ASTM C1472, Standard Guide for Calculating Movement and Other Effects When Establishing Sealant Joint Width, for determining appropriate movement joint width relative to the intended application and conditions.
These two photos of the same spot show what happens when transition joints are fi lled with a hard grout rather than the soft movement joint sealant. The cementitious grout and stone crack due to expected movements within the stone and the structure. It is a good example of why we need movement joints in tilework.

These two photos of the same spot show what happens when transition joints are filled with a hard grout rather than the soft movement joint sealant. The cementitious grout and stone crack due to expected movements within the stone and the structure. It is a good example of why we need movement joints in tilework.

2CrackedGroutDueToMissingTransitionMovemtJoint

Ensuring adequate design
The appropriate design of a movement joint is based on the tile assembly’s configuration and substrate type. The substrate must be structurally sound, meet relevant code requirements, and not exceed maximum deflection limitations (ranging from L/360 to L/720, depending on the material and the application). The general rule is these movement joints should be placed at the perimeters of tile and stone installations, at all transitions of planes or different materials, and within the field of tile.

Tiles at perimeters of rooms should have movement joints. Inside and outside vertical joints on framed walls should have movement joints and not be hard-grouted (as they so commonly are, alas). Bathtub or shower receptor to wall transitions should have a movement joint. In wet areas, movement joints are important not only to control movement, but also to act as a water-stop at those transitions, providing another layer of protection.

Whether due to thermal or moisture movement, shrinkage, freezing, or dynamic structural movements, all exterior stone assemblies—like this limestone fountain surrounded with granite paving—are going to move.

Whether due to thermal or moisture movement,  shrinkage, freezing, or dynamic structural movements, all exterior stone assemblies—like this limestone fountain surrounded with granite paving—are going to move.

TCNA states movement joints for interior applications should be placed at least every 6.1 to 7.6 m (20 to 25 ft) in each direction unless the tilework is exposed to direct sunlight or moisture, which would then require the movement joints placed at least every 2.4 to 3.7 m (8 to 12 ft) in each direction. For exterior applications, movement joints should be placed at least every 2.4 to 3.7 m in each direction.

TCNA recommends the movement joint width be a minimum of 9.5 mm (3/8 in.) wide for exterior applications when the field movement joints are 2.4 m on center (oc), but recommends a minimum of 12.7 mm (1/2 in.) wide joints for exterior applications when the field movement joints are 3.7 m oc. TCNA states:

minimum widths of movement joints must be increased 1.6 mm (1/16 in.) for each 9.44 C (15 F) tile surface temperature change greater than 37.8 C (100 F) between summer high and winter low.

The aforementioned ASTM C1472 is valuable because it provides the coefficient of linear thermal movement for different materials, along with the temperature range of various geographic areas and mathematical formulas to determine the required joint widths for the respective conditions.

To ensure a longlasting limestone installation, architects must specify the requirements for movement joint design and placement, along with the correct type of sealant for fi lling those joints.

To ensure a longlasting limestone installation, architects must specify the requirements for movement joint design and placement, along with the correct type of sealant for filling those joints.

To what degree the respective substrate needs movement joints depends on the standards the substrate must meet. For instance, a plaster substrate per ASTM C1063, Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-based Plaster, requires control joints installed in walls to delineate areas not more than 13.4 m2 (144 sf). The distance between control joints shall not exceed 5.5 m (18 ft) in either direction or a length-to-width ratio of 2.5 to 1.

Concrete also has standards that vary depending on its structure, thickness, and design mix.

Detail EJ171 states all underlying movement joints in the substrate need to continue through the tile assembly. Typically, this means that in addition to honoring the substrate movement joints, the tile assembly needs additional movement joints within its assembly.

If there is a mortar bed over the substrate, then the movement joint has to be continuous through it to the tile surface, which is considered an expansion joint. If the tile is being bonded to the substrate, then the movement joints not continuing up from a substrate movement joint are generic movement joints. These are often the same width as the grout joints if it was designed to work at that width. The movement joint widths within the tilework should never be narrower than the substrate joint on which it is placed.

Crack-isolation membranes
Some manufacturers of products meeting American National Standards Institute (ANSI) A118.12, Specification for Crack-isolation Membranes for Thin-set Ceramic Tile and Dimension Stone Installations, allow their membrane to cover non-structural movement joints (i.e. those that move horizontally, but not vertically) such as saw-cut or cold control joints. However, TCNA does not recommend this.

Structural expansion joints can never be covered with membranes as the vertical displacement cannot be mitigated with a crack-isolation membrane. (The membrane manufacturers require movement joints be installed within the tile assembly, and some allow those joints to not line up exactly over the substrate joints.)

The appropriate design of a movement joint is based on the tile or stone assembly’s confi guration and substrate type.

The appropriate design of a movement joint is based on the tile or stone assembly’s configuration and substrate type.

Each manufacturer of crack-isolation membranes may have different recommendations and limitations, so it is always important to follow the accompanying instructions. Some membranes are made of a bitumen material that is incompatible with certain types of sealants used to fill the movement joints.

TCNA’s Detail F125, “Partial- and Full-crack Isolation Membrane,” provide guidelines for isolating non-structural cracks with an ANSI A118.12 product. It is important to note this detail for both ceramic tile and stone applications recommends a movement joint be placed at one or both ends of the tile bridging the underlying crack, as recommended by the membrane manufacturer.

Types of movement joints
The different types of movement joints are shown in the TCNA Handbook in the EJ171 section. Expansion joints are normally considered structural joints that can possibly move vertically. They are found in concrete substrates to isolate one portion of the slab from the other, and in mortar beds as either an extension of the concrete expansion joint or just to isolate one portion of the mortar bed from the other.

A cold joint is the dividing point where two adjacent concrete pours were placed at different times. These weak points are more likely to develop cracks and have to be treated as a movement joint.

Construction or contraction joints are saw-cut concrete control joints that must also be treated as movement joints. The concrete is saw-cut at this predetermined spot, making it a weak point where the concrete will crack (rather than having it crack at a random location). There are also various types of perimeter movement joints, which are found at restraining walls or transition points from one plane to another that are all more likely to be subjected to some type of movement. Tile must be allowed to move to avoid damages.

Sealant considerations
Not only is the design of the movement joints important to a tile installation’s success, but so is the type of sealant or caulking used to fill those joints. TCNA EJ171 states a product meeting ASTM C920, Standard Specification for Elastomeric Joint Sealants, must be used to fill movement joints of all types. Such sealants include high-quality silicone, urethanes, and polysulfide materials. These types of sealants are normally rated as highly weather-resistant with high elongation properties, and high adhesion characteristics that come with 20-year commercial warranties. Too often, one finds installers using some type of acrylic, latex, or siliconized sealant, because they are easier to work with, but these sealants have low performance values and basically no warranty.

Various sealants have different physical properties and performance capabilities. TCNA and the referenced ASTM standards provide guidelines and nomenclature for designating the appropriate type, grade, class, and use for the intended application. For instance, some sealants are not suitable for foot or vehicle traffic, so one must specify “Use T” for those applications.

A traffic sealant should have a Shore A hardness of 35 or greater, which is critical because otherwise the surface could be dangerous to those who wear high heels. (Found on data sheets, Shore A is a physical property of all sealants; it indicates how hard it is in terms of resistance to penetrations or point loads.) High heels will penetrate a softer sealant and can cause a tripping hazard.

There are sealants with fire or acoustical ratings that are required for certain applications; some cannot be used in a submerged application, while others cannot be subjected to certain chemicals. Not all ASTM C920 sealants are compatible with natural stone and could cause the stone to stain. Some sealants require the surfaces to be primed after cleaning the joints and before installation. These are all important concerns to be addressed in the specification to ensure the correct material is used for the intended application.

Various sealants have different physical properties and performance capabilities. Traffi c sealants need a Shore A hardness of at least 35 to ensure those with high heels do not dig into the material, leading to trips and falls.

Various sealants have different physical properties
and performance capabilities. Traffic sealants need a Shore A hardness of at least 35 to ensure those with high heels do not dig into the material, leading
to trips and falls.

highHeelMarkOnSealant3highHeelMarksOnSealant01

It is important movement joints be properly constructed per industry standards. There are also numerous requirements sealant manufacturers specify in order for their products to perform as advertised. Sealants require only ‘two-point contact,’ meaning they are only to adhere to the two opposite sides of the movement joint for optimal performance. They are not to bond to the bottom of the joint, otherwise the sealant will not achieve the published elongation characteristics. A bond-breaking polyethylene tape or foam must be inserted into the joint prior to installing the sealant so the sealant will not bond to it.

To ensure the sealant achieves its published elongation characteristics, care must be taken to ensure it is applied neither too thin nor thick into the joint; the foam backer, installed at the prescribed depth, helps with this. The sealant must be at least 6.4 mm (1/4 in.) thick, and the width to depth ratio should be 2:1 for optimal performance. Generally, sealant companies want a minimum 6.4-mm wide joint, but 3-mm (1/8-in.) is acceptable for non-moving joints (e.g. adhered tile applications).

Additionally, movement joints must be completely filled with the appropriate backing below the sealant, so there are no voids to collect moisture. It is generally best to use closed cell foam, but some sealants require open cell to manage the sealants’ off-gassing while curing. For thin tiles—such as the 6.4-mm thick mosaics—or some of the newer large 3-mm thin porcelain tile panels, it is more problematic to try to install a bond-breaking tape in the movement joint. It is better to leave it out, since it is an adhered non-moving joint that will not require higher performance.

There are prefabricated movement joints made of metal sides and legs with plastic inserts adhered under the tiles on either side of the movement joint. There are also metal L-shapes that can be installed under the tiles on either side of the movement joint and then filled with the appropriate sealant. On one hand, these provide protection to the tile edges and the plastic inserts are conveniently replaceable; on the other hand, they restrain the tile movement since the metal angles are bonded to the substrate. This may not be a big problem if the tile is bonded well and they are installed frequent enough, but this author has seen cases where the tile was not sufficiently bonded, the movement joints were properly spaced, and the tile tented. Since tile assemblies move one way or the other, movement joints should not restrain movement.

Keystone Fashion Mall (Indianapolis, Indiana) has a striking tiled fl oor that benefi ts from having adequate consideration placed into the location and type of movement and expansion joint. Photo © Adam Novak Photography. Photo courtesy Crossville Inc.

Keystone Fashion Mall (Indianapolis, Indiana) has a  striking tiled floor that benefits from having adequate consideration placed into the location and type of movement and expansion joint. Photo © Adam Novak Photography. Photo courtesy Crossville Inc.

Circumventing aesthetic problems
Too often, movement joints are left out of installations with the common excuse being the owner did not want those ‘ugly’ joints marring their tiles. (Of course, their absence can cause even uglier failures.) When specifiers take the time to design the movement joints into the installation, they can accentuate features to make joints virtually unnoticeable.

Manufacturers of one-part silicone sealants have a broad range of colors available and on large jobs they will make custom colors to match the grout. Two-part urethane sealants can be mixed on the job by experienced sealant installers and can easily match the color of the tile grout. By placing the movement joints more frequently, they can be made narrower, matching the width of the grout.

For tile patterns with staggered joints, the designer can use the staggered grout joint (referred to as a saw-tooth joints or zipper joints) as a generic movement joint to make it less noticeable. When done well, movements are not noticeable and can enhance the installation features.

Specifying strategies
Architects should write the sealant specification for the tile and stone applications in Division 07 under “Sealants.” Still, detailed information should be provided in the Division 04 and 09 sections (for stone and tile), particularly if the tile installer is expected to install the sealant.

The following key points, as related to movement joints in tile or stone assemblies, should be included in the specification:

Part 1−General Requirements

  1. Refer to Division 07 for Movement Joint Sealants.
  2. Call out the key industry standards, which are: ANSI A108.01, Requirements for Movement Joints; TCNA Handbook for Ceramic, Glass, and Stone Tile Installation; Marble Institute of America (MIA) Dimension Stone Design Manual for Expansion Joints; ASTM C1242, Standard Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems; ASTM C1193, Standard Guide for the Use of Joint Sealants; and ASTM C1472, Standard Guide for Calculating Movement and Other Effects When Establishing Sealant Joint Width.
  3. Prepare a specific quality assurance (QA) section to verify performance of the ASTM C920 sealant material and to verify it will be suitable for the intended application. Test sealant for performance per ASTM C719, Standard Test Method for Adhesion and Cohesion of Elastomeric Joint Sealants Under Cyclic Movement. Test the peel adhesion of the sealant per ASTM C794, Standard Test Method for Adhesion-in-peel of Elastomeric Joint Sealants. For stone applications, test for staining per ASTM C1248, Standard Test Method for Staining of Porous Substrate by Joint Sealants.
  4. Require a letter from sealant manufacturer stating its product is suitable for the intended use, and outlining its warranty.
  5. For larger projects, specify a sealant installation company that specializes in installing sealants on a full-time basis.
  6. Require a mockup for approval of sealant color and application.

Part 2−Products

  1. Be sure to write performance specifications. Reference specifications only call out products that meet the minimum requirements—in other words, the least-expensive products with the lowest acceptable level of performance.
  2. Call out ASTM C920 sealants. Identify the application and the respective type, grade, class, and use to the intended application. Require a primer if sealant manufacturer requires it with the sealant. Call out the appropriate polyethylene backer foam. Specify the sealant color is to be approved by the architect or owner from the mockup.

Part 3−Execution

  1. Specify the specific movement joint details, for the respective application, from Detail EJ171 in the TCNA Handbook for Ceramic, Glass and Stone Tiles.
  2. Request installers properly clean and prime movement joints as required by the sealant manufacturer. The movement joints need to be completely open and free from any obstructions.
  3. Specify movement joint layout plans, and types of movement joints and sealants, as referenced in TCNA’s Detail EJ171. Tile installers should submit Requests for Interpretation (RFIs) if they are unclear with the requirements.
  4. Specify sealant product installation as per manufacturer’s instructions and industry standards. Similarly, products must be mixed following the manufacturers’ requirements. Further, temperature limitations must never be exceeded. Shading or heat should be required, and the work protected from weather and other trades.
  5. Specify the required sealant surface profile, such as “flush,” “concave,” “recessed,” or “fillet.” Vertical surfaces can be specified to be oriented vertically, horizontally, or at any angle in between so it can control water shedding.
  6. Provide a detailed quality control (QC) plan to be implemented by a third party.
Not only is the design of the movement joints important to a tile or stone fl oor installation’s success, but so is the type of sealant or caulking used to fi ll those joints. Photo courtesy Daltile

Not only is the design of the movement joints important to a tile or stone floor installation’s success, but so is the type of sealant or caulking used to fill those joints. Photo courtesy Daltile

Conclusion
To ensure a long lasting installation, it is critical architects specify and provide the requirements for movement joint design and placement, along with the correct type of sealant or caulking for filling those joints.

In more than three decades, this author has never investigated a tile or stone failure to find all the industry standards and manufacturers’ instructions were followed. Further, the failure is never due to one deficiency, but rather many compounding ones.

The industry standards represent years of experience and scientific testing from a consensus group of industry professionals who volunteer their time and efforts to help architects, installers, and owners have successful tile and stone installations. The key to a successful tile and stone installation is to follow industry standards and to write good specifications. CSI’s MasterFormat and SectionFormat provide the structure for this. When the resulting construction documentation is used correctly and thoroughly, it limits both the designer’s and client’s risk and liability in ceramic tile, glass tile, and stone applications.

Donato Pompo, CTC, CSI, CDT, MBA, is the founder of Ceramic Tile and Stone Consultants (CTaSC), and of the University of Ceramic Tile and Stone (UofCTS). He has more than 35 years of experience in the ceramic tile and stone industry from installation to distribution to manufacturing of installation products. Pompo provides services in forensic investigations, quality control (QC) services for products and installation methods, training programs, testing, and onsite quality control inspection services. He received the 2012 Construction Specifier Magazine Article of the Year Award. Pompo can be reached at donato@ctasc.com.

Continuing the Debate on Solar-driven Moisture

Our January 2013 article, “Ensuring Moisture Protection for Manufactured Stone,” written by Jeff Diqui, Arch. Eng., CSI, resulted in a letter to the editor from another frequent contributor to The Construction Specifier.

In the spring, Maria Spinu, PhD, LEED AP, e-mailed her comments:

I want to compliment Mr. Diqui on a generally well-written and informative article, but I wish to address the statements made around solar-driven moisture. He wrote:

A related effect in adhered masonry veneer cladding is inward vapor drive, which can occur in warm weather. It forces moisture stored in the masonry through vapor-permeable housewraps and building papers and into the sheathing and stud bay. Continue reading