Building Movement Joints and BIM

Computer modeling allows greater visualization, functionality, and design success in creating buildings that are allowed to move safely.

Peter J. Arsenault, FAIA, NCARB, LEED-AP

Most of us learned in school that, contrary to public perception, buildings move. Specifically, different portions and parts of buildings move relative to each other and in so doing create forces and stresses on building materials. This is a fairly straightforward concept to comprehend in theory, but in practice there are many variables and differing conditions to consider. Nonetheless, textbooks and trade publications tell us that every designer of buildings must develop a sure sense of where movement joints are needed and a feel for how to design them. Examples are often given of numerous buildings that are built each year designed by professionals who have not acquired this intuition. The result is that many of these buildings are filled with cracks even before they have been completed. Worse, some develop significant material and structural failures that require costly retrofit approaches that could have been avoided if the design were proper in the first place. This article will look at some of the science and the art of incorporating appropriate movement joints into buildings and how to use Building Information Modeling (BIM) as an effective tool in the process.

Sources of Forces

The movements within a building are recognized in a number of standards, mostly as they relate to materials and civil/structural engineering. For example, the American Society of Civil Engineers (ASCE) publication 7-02 titled "Minimum Design Loads for Buildings and Other Structures" states, "Dimensional changes in a structure and its elements due to variations in temperature, relative humidity, or other effects shall not impair the serviceability of the structure."

This statement first recognizes that there are a number of potential causes of internal forces that must be taken into account in the building design. It goes on to point out that it is the serviceability of the structure that is being protected. Such serviceability might include things like the integrity of a material, the overall structural system, the use of the building, or its ability to remain weather-tight. In essence, there is recognition here that buildings that do not contain appropriate movement joints will inevitably create their own at the points of maximum stress such that cracks, spalling, or outright breaks or failure of a material can occur.

Buildings move - both in appearance and in reality. Dancing House by Frank Gehry Photo © Dino Quinzani. "Case danzanti." Online image. 06 Aug. 2008. File: Case danzanti.jpg. Wikimedia Commons. Wikipedia. 11 Oct. 2010.

There are at least six generally recognized forces that cause movement in buildings along with potential problems as identified below:

Thermal expansion and contraction. It is well documented and understood that heat causes solid materials to expand and cold causes them to contract. In situations where materials are unrestricted on at least one end, then there is really no problem-they will grow and shrink without impact on things around them. However, when the materials are rigidly connected to other materials, the expansion and contraction pushes or pulls on the adjacent connecting materials causing structural forces of stress and strain. How much movement and how much force will depend on at least two variables: the material itself and the variation in the amount of heat or cold.

Coefficients of linear expansion for different materials.  Table 1
Materials	Coefficient of Expansion (in/in/ËšF)
Wood	3.0 x 10-6
Clay or Shale Brick Masonry	3.6 x 10-6
Lightweight Concrete Masonry	4.3 x 10-6
Glass	4.4 x 10-6
Limestone	4.4 x 10-6
Granite	4.7 x 10-6
Normal Weight Concrete Masonry	5.2 x 10-6
Concrete	6.0 x 10-6
Cast Iron	6.1 x 10-6
Structural Steel	6.5 x 10-6
Wrought Iron	6.7 x 10-6
Marble	7.3 x 10-6
Copper	9.3 x 10-6
Bronze	10.0 x 10-6
Brass	10.4 x 10-6
Aluminum	12.8 x 10-6
The smaller the number, the less thermal expansion per degree Fahrenheit Courtesy of Nystrom, Inc. ; compiled from various data.

Every material has, among its other physical properties, a thermal sensitivity factor that is expressed as a coefficient of linear expansion. Because this physical property is so well known, virtually all common building engineering materials have been tested and coefficients of expansion (contraction) have been determined. These coefficients are expressed in terms of very small fractions of an inch for each degree Fahrenheit of temperature change (see Table 1). At the low end of the scale, wood and glass tend to expand and contract the least when subjected to temperature changes while metals such as bronze, brass, and aluminum tend to move the most.

The amount of heat or cold that affects a material depends on its source. Materials exposed to the weather throughout the year will experience the cyclical daily, weekly, monthly, and annual changes relevant to the local climate. That means that the materials could be exposed to temperature swings of up 100 degrees or more in some locations over the course of a year with instances of 30 to 40 degrees of temperature swings possible within 24 hours. Materials that are kept inside a heated and cooled space may experience very little temperature change, perhaps 20 degrees or so. In addition to the air temperatures, there may also be isolated sources of heating and cooling that occur both inside and outside such as direct sun exposure, mechanical equipment proximity, industrial processes, etc. Since the amount of movement of a material is a direct result of the difference between the starting temperature and the ending temperature that is experienced, planning for the correct range is significant.

Water impact. Water in the form of vapor, rain, or other precipitation can cause materials to expand and contract if they are porous or if their water protection is compromised. In normal temperatures, water can soak into certain materials, including many masonry products, causing them to swell. As the water evaporates, the material will shrink back. Either form of movement may cause forces on the material affected or on adjacent materials. In freezing climates, the presence of water takes on an additional concern. Water is one of the few materials that performs inversely to most materials, meaning that it expands as it gets colder (freezes) and contracts as it gets warmer (unfreezes). Hence, water that seeps into a crack or opening in a building might harmlessly drain away or evaporate. However, if it gets trapped inside a material and freezes, it will expand and cause significant force on that material. This force is one of the chief causes of spalling in masonry and concrete work.

Vertical displacement. It is important to realize that buildings can move in all directions (see Figure 1). Movement of a building in the vertical direction might occur from thermal or moisture impacts as described above, but it is likely to be more significant if differing soil and foundation conditions are encountered across a building. Different portions or wings of a building may be of different heights and sizes and therefore will likely have different types of foundation designs. Where these different foundations meet, there may be a difference in the rate or amount of settlement that occurs on between the two. This condition might also apply or be exacerbated by different soil conditions that respond differently to the building loads imposed on them. The differences are usually calculable and can be accommodated in the design, but allowing for the vertical displacement that may occur regardless of the compensating design, is obviously more prudent.

Lateral shear. Horizontal forces on a building can come from things such as wind loading or external building attachments. These forces can be accounted for in the basic structural design, but it may well be within normal tolerances to allow for some level of movement, particularly at extreme "worst case" conditions.

Forces in buildings can exert stress and strain along a vertical axis, along multiple horizontal axes, or in multiple directions during a seismic event. Illustration: Nystrom, Inc.

 

Seismic forces. Designing a building to survive the multiple forces of an earthquake is clearly more involved than a single directional force. Seismic forces can affect a building in any direction along multiple horizontal and vertical axes. The degree of these forces that need to be addressed are mandated by codes and good structural system design standards. Allowing portions of a building to move independently from one another during an earthquake is a proven method to address the impact of those seismic forces.

Construction forces. Certain materials may experience or exert particular forces during construction. For example, the chemical process of concrete curing causes it to shrink and possibly crack. Masonry may swell and shrink during installation and set up. Materials that are designed to be used in spaces that are heated and cooled may be subject to weather conditions during construction that they weren't otherwise designed for. All of these potential construction forces need to be taken into account.

Degrees of Separation

The fundamental approach of separating a material, a building system, or the building itself into independent portions or sections is the starting point for all movement joint discussions. This requires a basic understanding of different types of joints, their general impact on the building, and where they are used. BIM can be an incredibly useful and important tool not only to locate key areas where different joints should be used, but also to detail and integrate the joints into the rest of the construction. Full three dimensional modeling of a building will demonstrate critical areas for joints to occur between the structural system and other materials and building systems. Integration of the details of these joints will necessarily need to be cross discipline affecting the design of the structure, architecture, interiors, roofing, and in some cases, the mechanical systems. Hence the cross-discipline capabilities of BIM will prove highly valuable in correctly locating and coordinating the design of building joints of all types. It is important to acknowledge that the joint must be calculated and sized in terms of its minimum and maximum opening, with the average opening often being its nominal size (see Figure 2). The common types of joints are described below in terms of the type of gap or separation that is needed. In the subsequent section we will discuss how to fill, cover, or otherwise treat these joints.

The use of BIM can help determine the nominal, minimum and maximum joint size and show the impact of expansion and contraction on building systems. Illustration: Nystrom, Inc.

Control joints (also called construction joints). This is one of the most common types of joints and is typically described as an intentional line or break that is created in the surface of a material. Its role is to encourage and direct anticipated cracking in an orderly manner instead of random, uncontrolled cracking. Control joints are almost always used in concrete floor and wall surfaces which are prone to cracking due to shrinkage during curing (see Figure 3). They may also be used in masonry construction to absorb other forces. In any case, they typically are spaced fairly close together meaning that the amount of force that each control joint is absorbing is relatively small. As such, they do not usually fully penetrate all layers of a structure, rather are cut about 25 percent or so into the depth of the material. The spacing of control joints across a smooth plane such as a wall, floor, or roof surface will vary and depend on the material used as shown in Table 2.

Control joint pattern in concrete floor slab showing diamond shaped isolation joints around columns Illustration: Nystrom, Inc.

 

Recommended control joint spacing for various materials Table 2
Materials	Control Joint Spacing
Concrete Slabs on grade	24 times slab thickness - rectangular sections should restrict longer side to 1.5 times shorter side
Concrete exterior walls	Every 20 feet
Type I Concrete masonry walls	Â
Unreinforced:	The lesser of 40 feet or twice the wall height
Reinforced:	The lesser of 50 feet or three times the wall height
Type II Concrete masonry walls	Â
Unreinforced:	The lesser of 20 feet or twice the wall height
Reinforced:	The lesser of 25 feet or three times the wall height
Stucco Walls	10 feet
Some general "rules of thumb" are shown, but should be verified for particular projects based on specific project conditions. Courtesy of Nystrom, Inc. ; compiled from various data.

Structure/enclosure joints (sometimes called isolation joints). Any place in a building where a non-structural component meets a structural component the potential exists for an unwanted transfer of forces. Hence, a full-depth joint or separation between these components is needed. Examples of this type of joint would include the top of a non-load bearing partition that connects to the underside of a structural floor slab or a non-structural exterior wall or spandrel panel that connects to a structural frame. When the different components are comprised of different materials, the rate of expansion or contraction will be different even though they are exposed to the same conditions. Hence the separation is intended to allow the resulting differences in movement instead of transferring a structural force onto a non-structural component. This might be accomplished by the use of a combination of rigid and flexible anchors along with gaps between the sections of non-structural components to allow each piece to float or move independently from the other. In some cases, such as a concrete slab on grade adjacent to a concrete foundation wall, a separation is warranted even though the materials are the same. The reason here is due to the fact that the two components will settle (vertical displacement) differently due to the different loading conditions that each are subject to-the wall carrying significantly more weight in the form of structural building loads while the slab on grade is typically carrying only its own weight and any live loads. The differences between the forces transferred to the soil could cause different settlement conditions over time, causing cracking or failure if not isolated. Around columns, it is common to use diamond-shaped isolation joints that meet with concrete control joints to cleanly address multiple forces.

Abutment joints. In building situations where two different types of construction meet or abut each other, a full depth joint is needed. This is common in cases where, for example, a framed wall system abuts a brick or masonry wall system. Each system can be expected to move at different rates due to the same or different forces that each one is subjected to. Hence, the separation is made wide enough (typically 1/2 inch or less) to allow the movement based on the size of the abutting systems and the spacing of other types of joints in each system. Abutment joints are also needed wherever new construction abuts with older construction, even if the materials are the same. New masonry mortar will typically shrink as it sets, so if it is tied in or interleaved with existing mortar, it will cause cracking and breaking. Instead, a continuous, flexible separation that completely separates the old from the new will prevent this from happening. Regardless of material or construction types, abutment joints are also appropriate wherever a building portion that is heated or cooled abuts a portion that is not similarly heated or cooled such as a warehouse or canopy. The different temperature conditions will result in different amounts of thermal expansion and contraction which need to be accounted for.

Building separation joints. In large buildings or buildings with multiple wings, towers, or other distinct sections, particular attention needs to be paid to separating these sections to avoid the transfer of forces from one section to another. While these building separation joints are sometimes referred to as expansion joints, in reality they are intended to separate a large building into smaller discreet sections that can act independently from one another (see Figure 4). In so doing, they can then handle a variety of movement types beyond the large-scale thermal expansion and contraction described above. Other forces such as vertical displacement or settlement of foundations, large-scale material shrinkage or creep, and seismic activity can be accommodated by using this design approach of creating structurally separate building portions. In these cases, the full three dimensional section needs to be separated such that a continuous break is formed along walls, floors, roof, and other building elements. Each section needs a distinct structural system on either side of this continuous break, such that, for example, two columns and beams may be required where only one would otherwise be provided. The structural systems must not span across the joint or the purpose of the joint is lost.

Building separation joints need to occur wherever there is a change in building mass or to separate large masses into smaller sections. These joints need to penetrate the entire 360 degree profile of the separations as shown in the BIM illustration on the right. Illustration: Nystrom, Inc.

 

Given the multipurpose nature of these joints, they should be considered early in the design process by all disciplines involved including architects, structural engineers, soils engineers, seismic consultants, etc. The locations of building separation joints will in large part be determined by the final architectural massing of the building and may be a consideration in that process. Keep in mind that sections that can be identified vertically (e.g., a tower adjacent to a lower section) are as important as sections that can be identified horizontally (e.g., wings off of a central core). As with pure expansion joints, large sections over 150 to 200 feet long will require additional joints to be located in concert with the rest of the building design.

Expansion joints. This term has been used somewhat generically to refer to all types of building joints. However, it is more appropriately used to describe only full depth joints that are larger (wider) than the other joints described above with the intent of allowing movement specifically due to thermal expansion and contraction. In walls, floors, ceilings, and roofs, they should serve as open, full-depth seams that can open and close slightly to allow thermal movement in adjacent materials. Expansion joints may also be appropriate at locations of structural weakness defined as anyplace a geometric change occurs in a wall or other surface. This would include corners, changes in heights, changes in width across a surface (such as around large door or window openings), or other significant geometrical changes. Note that some of these same conditions may be treated with multiple control joints if the relative size of the change is small or if enough multiple joints are used (as in around closely spaced multiple window openings). But full-depth expansion joints will still be needed at all major geometric changes or over long sections of surfaces. Unbroken lengths of masonry surfaces should generally not exceed 125 feet without an expansion joint while concrete and steel surfaces can usually go up to 200 feet before needing an expansion joint(see Figure 5). These distances and the width of the joints are calculable from an engineering standpoint and may be adjusted based on other factors such as total temperature swing exposure or building shape (i.e. rectangular vs. non rectangular). It is the prerogative of the designers to choose the best locations and spacing of these joints consistent with the overall design and appearance of the building.

Expansion joint locations can be dictated by the size or shape of a building-or both. Illustration: Nystrom, Inc.

Integrating Joints into Buildings: Fill, Cover, or Conceal?

So far, we have described the physical joints or separations in structural and architectural materials and systems. If we were to stop at this point and look at our BIM model, we would see literal gaps and openings in our walls, floors, roofs, etc. Similarly, at a partially complete point in the actual construction, we should also see exactly those intentional gaps. However, to get to the finish stage, those gaps need to be dealt with in order to address the other needs of the building such as creating a weathertight building envelope, maintaining fire separations, or providing a finished surface consistent with the aesthetics of the rest of the building. Fortunately, there are a wide variety of choices and customized products available to architects and designers to choose from including filling, covering, or partially concealing these joints. The details of each method are different not only for the type of system or product used, but they also have different impacts on the details of the materials forming the joints that need to be coordinated. This is a situation where the use of BIM can make the process of design much easier. Manufacturers of building movement joint products have created BIM families of their products that can be referenced, tried, coordinated, and fully integrated into the full model. In the process, details of opening width, any needed special edge conditions, etc. can be determined and coordinated to assure that the joint is designed and constructed to perform successfully.

Our next step in the process of designing joints into buildings, then, is to choose the appropriate method of treating the gaps from the common choices below:

No fill. In cases where the joint does not fully penetrate the material, as in a concrete control joint, there may be no need to fill in the joint. Rather, the joint is cut only into the surface and is able to either channel away any water (as in a sidewalk), designed to be part of the finished surface (as in a sealed interior concrete slab), or covered over (as in a floor slab with flooring on top).

Filler systems. In situations where a filler is clearly needed, it may be appropriate to use a flexible or compressible material that is adhered or anchored to the adjacent building materials (see Figure 6). As the building elements move, the filler compresses or expands in one or more directions while still staying consistently and uniformly secured to those materials. Essentially, there are two general options to consider. For small gaps of about 1/2 inch or less, a backer rod and flexible sealant (such as silicone) are an appropriate and common solution. In cases where multiple wythes of masonry are involved, a flexible spline or waterstop may be warranted in addition to the sealant. For larger openings, a preformed elastomeric or other compressible filler is appropriate. These fillers are manufactured items that can come with or without aluminum frames depending on the application and the requirements. All manufactured fillers of this type will have a specific range of expansion with a minimum and maximum size that it can accommodate, meaning that it needs to be matched to a joint that falls within that range of calculated movement. These products can be used to fill gaps ranging from 1/2 inch up to approximately 6 inches in floors and 24 inches in walls. Filler products can be selected from numerous choices based on varying needs for durability, weather-sealing, finish color, and resistance to different forces. Unframed compressible fillers can either be solid-shaped material or extruded in a multiple "bellows" form that is adhered to the sides of the joint. If a framed filler is used, it is typically screwed or anchored into the adjacent materials allowing the filler to bridge the space between the frames, again using either a solid or bellows-style filler material.

Flexible filler installed in a building movement joint shown in place on the left and in a BIM illustration on the right Photo and BIM illustration: Nystrom, Inc.

Slide-by cover systems. An alternative to filling a joint is to cover over it with an arrangement of metal plates that slide past one another (see Figure 7). In this manner, there is not necessarily a filler material that is being compressed and expanded. Instead, each metal plate is secured on only one side allowing the overlapping sections to move or slide by each other such that the movement can occur while still keeping the gap covered. The metal plates can come in a variety of finishes, durability, and colors to accommodate different applications. While commonly referred to as expansion joint covers, these covers can in fact be used to accommodate other types of joints as well such as abutment joints and building separation joints for a variety of forces including seismic activity.

Concealed cover systems. In some cases, the preferred approach for design and aesthetic reasons is to conceal a substantial portion of the cover thus leaving only very little metal exposed. This approach is often very desirable when expansion joints or building separation joints are required that are very wide (2 inches or more). The partial concealment of the metal is typically accomplished through a recessed section of the cover that allows for finish material such as flooring or wall covering to be inserted and adhered. This finish material can match the surrounding surfaces or provide an intentional accent color. Detailing and installing these systems correctly is obviously important since installing the finish material improperly over the moving portions of the cover will undoubtedly crack or break that material into pieces. Treating joints in this manner is a case where manufacturer's information and incorporating the product into a BIM model are extremely useful both to help with the technical installation details and to visualize the finished design appearance.

Slide-by metal covers installed in a building movement joint Photo and BIM illustration: Nystrom, Inc.

 

Detailing for Specific Locations Using BIM

In the design of a building, we have now identified the need to first recognize and deal with the forces that cause movement in a building. We've looked at the different types of joints or gaps that can be used to allow or dissipate those forces, and the approaches that can be used to fill or cover those gaps in order to accommodate the other general needs of a building. The final step in designing and specifying building movement joints is to select and detail the specific products or assemblies appropriate to the different locations where they are needed. BIM has been referred to as a way to investigate the options and visualize the alternative conditions thus far. Now it is appropriate to use it to make the final selections and assure that all conditions are fully coordinated. Because there are many manufactured joint products that are available in BIM format, it is more straightforward than ever to use this available library to make a final selection and in some cases actually customize the product to suit a project's needs. In particular, it is increasingly common that manufacturers will offer coordinated floor, wall and ceiling systems that match in appearance and finish. The benefit to the building design, then, is a consistent, continuous appearance across different building surfaces and adjacent materials. Using the manufacturer's BIM files in the overall computer model will allow for full visualization of this appearance on the different affected surfaces and allow the designers to make the best informed decisions on product selection.

Six specific joint locations are discussed below with some corresponding selection criteria to consider when choosing which ones to specify. Each of these assumes that the types of forces (horizontal, vertical displacement, seismic, etc.) have already been identified and the type of joint needed (expansion, abutment, building separation, etc.) has been analyzed and determined.

Interior floor systems. (See Figure 8.) Among the first criteria to consider for joints in active floors is how much traffic and what type will pass over it? Schools and auditoriums will be subject to a lot of pedestrian traffic. Airports, hotels and hospitals will add any number of wheeled devices to the traffic mix that need to be considered. In airports, this could include a range from heavy but large wheeled motorized equipment such as multi-passenger carts down to small wheeled items like suitcases with concentrated loads. Hospitals will have a similar range from large wheeled beds and gurneys down to small wheeled rolling monitor and equipment stands. Warehouses, manufacturing plants, and retail locations may have truly heavy-duty traffic such as forklifts and delivery carts. Each type of traffic will have a different overall impact on the floor joint system and different resulting direct impact based on the actual pounds per square inch exerted, ease of the wheels passing over the joint, etc.

An interior floor joint cover in place on the left and in BIM detail on the right. Photo and BIM illustration: Nystrom, Inc.

Of course, all of these locations will also need to meet ADA standards and provide a finished joint that is flush within 1/4" of adjacent surfaces if the joint top is flat or 1/2" if it is beveled. If the floor joint occurs along a section where the floor is not level or otherwise uneven on adjoining sides, then that adds another item to the criteria for selecting a manufactured product since it will obviously have to accommodate that unevenness. In light-duty situations, a compressible filler or special sealant may be appropriate. In most cases, however, the criteria for floor joints will more likely dictate a covered system, with or without concealment, in order to remain reliable over time. These covers may use a single or double cover "wing" which slides, may be hinged to accommodate uneven conditions, or may have particular features for floor edge conditions. Floor joints that meet seismic requirements will also meet many other criteria, but should be selected based on the seismic requirements of the building first.

Interior wall and ceiling systems. Since interior walls and ceilings are subject to less impact from usage than floors, the joint treatment is usually simpler. As mentioned earlier, there are benefits to selecting a coordinated system from the same manufacturer that includes the floor, wall, and ceiling joint in order to achieve a consistent, unified appearance and design. These coordinated systems will pay particular attention the detail of the meeting points or corners of the joints where the different surfaces intersect. After that, consideration should be given to the need for general durability, vandal resistance, or seismic consideration which is usually the most stringent criteria. Many choices are available in both compressible filler and cover plate systems in regards to appearance, sight lines, and colors. Hence, it is likely that it will be readily possible to select something consistent with the overall interior design of a particular project. The key from a design standpoint is to actively review the choices and use the joint as a design element that either blends in with the surroundings or accents them. Either way, it is an element that should definitely not be ignored in the design.

Exterior wall systems. Here, we are dealing with the building envelope, which means the joint needs to accomplish all of the things that the rest of the wall does from a building enclosure standpoint. Sealing out water and wind are, therefore, among the first criteria while overall durability and vandal resistance will likely come into play as well. Fillers and covers are both commonly used in this situation with a variety of colors and finishes readily available. If the building is designed for seismic forces, the choice of manufactured products may be reduced somewhat, but appropriate selections can still be made that satisfy the other general criteria as well.

Exterior floor and parking systems. (See figure 9.) These joints may come under the greatest level of exposure from a variety of sources including the weather, vehicular traffic, or other conditions. Solid elastomeric filler may be appropriate for certain conditions such as the need for relatively quiet sounds as vehicles drive over them. In other cases, heavy-duty metal cover plates may be more appropriate for heavy vehicle loads or seismic forces. Finishes and colors may be a bit more limited, but certainly acceptable for this application.

An exterior floor joint with a cover shown in BIM detail on the lower right and installed at Target Field, Minneapolis, MN Photos and BIM illustration: Jason Englund

Exterior roof systems. Building separation, abutment, and expansion joints that extend through the roof will need to meet the rigors of maintaining a watertight roofing membrane. Essentially, there are two options for covering joints in roof systems. The first is a flexible bellow that can be installed along horizontal or vertical surfaces and be flashed into the roofing system to allow both movement of the bellows and integrity of the roofing membrane. They often include integral metal flanges to aid in the installation and flashing and have been used successfully and routinely in many types of roofing installations. The second type is a metal joint cover that can be used on flat or sloped roofs. These metal covers can be engineered to address snow and ice loads and provide the additional advantage of being puncture-proof.

Fire barrier systems. In the event that any of the above joint systems penetrates a wall, floor, ceiling, or roof that is also fire-rated, an additional fire barrier product will need to be added to the joint system (see Figure 10). Obviously, the first criteria to consider in selecting such an additional product is the degree of fire rating needed-1, 2, 3 or 4 hours. It will also be important that the selected product is compatible with the full joint and/or covers and does not impede their correct function. Further, the fire-rated barrier will need to be flexible and able to move as well. It is logical, then, to specify that these products come from the same manufacturer as the full joint system.

For any type of joint to achieve a fire rating, an additional fire separation product must be installed first before a joint filler or cover is installed. BIM illustration: Nystrom, Inc.

 

Conclusion

With an understanding of the forces, joint types, filler or cover options, and the use of BIM to visualize solutions, building movement joints can be readily integrated into a design to solve a myriad of movement scenarios. Incorporating manufacturer's information and BIM files allows the architect to select from custom sizing, materials, and color finishes ensuring that whatever is needed for a particular project is appropriately selected and properly detailed. Using the information above will help assure that designs and specifications will achieve the desired success and prevent the deterioration that would otherwise occur in a building from movement.

Peter J. Arsenault, FAIA, NCARB, LEED-AP is an architect and sustainability consultant based in New York State focused on sustainable design and practice solutions nationwide. He can be reached at www.linkedin.com/in/pjaarch

Nystrom is a leading direct-to-site provider of complementary building products and services for the commercial construction industry. We simplify 10 categories of Complementary Building Products including: Expansion Joint Covers, Smoke Vents, Louvers, Roof Hatches, Floor Doors, Access Panels, Entrance Flooring Systems, Stair Treads & Nosings, Wall & Door Protection and Fire Extinguisher Cabinets. Nystrom is committed to delivering on our promise of "Right to Site."  http://www.Nystrom.com/