Changing the Language of Concrete: Communicating clearly with the project team

by Katie Daniel | July 17, 2017 9:43 am

All photos courtesy DIALOG

By Christopher Bennett, CSI, Assoc. AIA, Keith Robinson, FCSC, FCSI, RSW, LEED AP, and Rae Taylor, PhD
The Inuit have many different words for snow. ‘Aqilokoa’ means ‘softly falling snow,’ while ‘piegnartog’ describes ‘snow best for driving a sled across,’ and ‘pukak’ refers to ‘fine, powder-like snow on the ground.’ There are dozens more words describing frozen water in its many different forms. To those in warmer climes, having so many words for snow may seem superfluous, but to the Inuit, being able to both accurately communicate and describe their surroundings is a matter of survival and illustrative to their way of life.

In the construction world, accurately articulating concrete’s structure, form, and esthetics is crucial to success, yet not enough members of the project team are fluent in the material’s language. It is not uncommon to hear people use the terms ‘cement’ and ‘concrete’ interchangeably despite the obvious fact the former is a component of the latter. People with many years of construction experience often do not know different types of concrete exist and with very specific purposes (Figure 1).

Participants communicate differently
Design professionals and contractors speak differently about concrete, and it could even be argued they do not view the material’s end function the same way. Their approaches to communication vary because of how they approach their respective roles in construction, and are offset sufficiently that the path to clear instruction is lost.

Contractors approach communications pragmatically and require explicit instructions with expectations stated clearly and in detail, leaving no avenue for interpretation. Even when written specifications or drawings do not meet this expectation, their default position is to view the documents as a clear intention of fact.

Design professionals, on the other hand, deal with communications defined by implicit outcomes—with documentation prepared in a way that can be understood through often-unexpressed concepts. They rely on specifications and drawings that depend on references to standards, guidelines, and other sources not directly written. In other words, the instructions are not explicit and require the contractor to interpret potential outcomes based on the total content.

When it comes to concrete, its placement, and formwork, the design professional knows exactly what he or she wants, but may not fully appreciate the terms the contractor needs to price, purchase, and place the material. The design professional will name a project where concrete with an acceptable architectural finish can be found without understanding the conditions in which the representative sample was placed and how they differ from the current circumstances.

The contractor is looking for temperature, humidity, and other environmental conditions needed to make concrete look the way the design professional requires. Architects or engineers understand formwork and concrete mix influence esthetic outcomes, but they lack the practical experience to describe other controlling factors affecting the final placed concrete.

Even among design professionals, engineers and architects use different language, or—worse yet—try to employ each other’s terms to describe what they require. As one example, architects will use floor flatness (FF) and levelness (FL) to describe appearance outcomes for concrete slabs. The problems with this approach are further compounded when the architect uses the same descriptions for elevated slabs, where flatness values are greatly diminished and levelness does not apply.

What the architect is describing are requirements for floor smoothness and evenness—reducing the ripples and ridges associated with concrete floating and trowelling, as well as improving the planarity of the surface to reduce the degree of slope of the raised slab between structural bays. The engineer, however, uses the FF and FL values to describe expectations to control surface features that can potentially affect the safety of people using the floor surface, with the understanding there is limited applicability to floors not on-grade. Structural requirements do not typically align with architectural expectations, so this failure to communicate can cause problems unless discussions happen well in advance. With advance discussions, however, it is entirely possible architectural requirements can be clearly identified on structural drawings and in the specification content.

Figure 1: Using data drawn from the fourth edition of McGraw-Hill Education’s Concrete: Microstructure, Properties, and Materials, this table outlines special hydraulic cements, along with the details of their composition and examples of their suitable use.
It is important to seek training beyond American Concrete Institute (ACI) flatwork certification to achieve success when working with architectural exposed structural concrete (AESC).

Documents communicating differently
Perhaps the most poignant example of conflicting language in concrete construction comes when attempting exposed finishes. However, this is not so much a fault of different definitions between members of the project team, but rather of existing lingua franca in construction document practices.

Not all firms have specifications for architectural exposed structural concrete (AESC). Rather, they have language in their exposed concrete specifications that refer to MasterFormat Section 03 31 00–Structural Concrete, despite the fact these documents were never written to be used to create exposed architectural finishes. MasterFormat has anticipated the need for cast-in-place concrete where appearance is a prime consideration, and appropriately named it Section 03 33 00–Architectural Concrete. This section can describe the performance expectations and modifications to standard structural concrete to achieve the required finishes, which are poorly represented even where guide specifications do exist.

Lobbies used to be covered in carpet. Retail stores across the country were covered with millions of acres of vinyl composite tile (VCT), and manufacturing facilities primarily planned on epoxy finishes throughout the facility’s life cycle. Fifteen years ago, when there was a drive to sustainable and durable finishes requiring minimal replacement, this changed—but construction documents did not. Concrete already formed part of the building structure—it encapsulated fly ash and other recycled components, and had an expected life cycle equal to that of the building.

No design team would ever specify “slab must curl to ensure uneven aggregate exposure at joints and edges,” “cover floor in map cracks,” or “confuse and anger owner by creating different outcome than shown in rendering.” Nevertheless, this is exactly what thousands of firms end up doing on a daily basis by continuing to use structural concrete specifications that were never intended for AESC.

FF and FL are no longer simply measures of safety or performance requirements for intended use, but also benchmarks of uniformity of aggregate exposure and project cost. Older methods of curing and finishing may no longer be relevant in AESC if they detract from esthetic, long-term maintenance, or other considerations.

To compound matters, training programs have not been updated to describe this new field of AESC and teach its vocabulary. For instance, Division 03 30 00 may require use of an American Concrete Institute (ACI)-certified concrete flatwork finisher, but ACI certification does not address concrete with an exposed architectural finish. In this instance, firms are relying on non-native language to direct contractors unfamiliar with AESC requirements toward a design intent they cannot possibly meet. This is unfair to contractors, who often bear the financial responsibility that comes from not having clear, concise, complete, and correct language.

What happens when we all speak the same language?
The culture and language of any organization or group of people is passed from top to bottom, but also horizontally. As people join at any level, they learn from those who have been there longer. There is an informal education on ‘best’ work practices, who to trust, and who to listen to. Without communication in all directions, it is easy to create barriers and misconceptions based solely on what perspectives are immediately around you. This can lead to an ‘us versus them’ mentality, which does not help the project or owner, or further development of the project team
members. Professionals must allow each other the opportunity to ask questions and the patience to discover the answers together.

Architects and engineers must learn the language of concrete not simply in how it is used in documents and situations familiar to them, but also by getting out onto the site and observing conditions affecting placement, construction of formwork, and scheduling of concrete delivery. By becoming a part of the experience and learning from the contractor members of the project team, design language can become more precise, while also creating common bonds and a drive to understand each other’s needs.

At the University of Manitoba’s Centre for Architectural Structures and Technology (CAST), these ideas are already well in motion. For students attending CAST, architectural research embraces both the design and hands-on components of construction. This is a fundamental change to how architects, engineers, and designers have been educated in the past, but provides graduates with both theoretical and empirical foundations, which will make them better communicators with all members of the project team. (For more on CAST, visit[4].)

Unfortunately, constructors—usually outliers to the design process—do not yet have an avenue to pursue cross-disciplinary studies like their design counterparts. There are training and certification opportunities from manufacturer and contractor organizations, but these are proprietary at worst, and exclude real-world experience and perspectives from architects, engineers, and designers at best. There is little chance contractors and designers will interact directly during a live project, so it is even more important formal training is available in a safe and productive atmosphere where more-robust professional development can occur. Having a strong grasp of design language and perspective helps professionals both make the right choices for the benefit of the project and understand better choices do not necessarily lead to higher prices or longer construction schedules.

Concrete construction is more than integrated project delivery—it is an integrated design process often lacking in cross-discipline co-ordination. Understanding each other’s point of view—and being able to describe similar concepts using words all parties agree have a common interpretation—should be the first bulwark for ensuring success.

Communication benefits everyone involved with the project, but is only possible when everyone’s definition of concrete is understood. Using the proverbial ‘concrete eraser’ (i.e. employing a jackhammer to selectively remove concrete that fails to meet expectations) to fix problems is never going to be as effective as a simple meeting between professionals that understand one another and empathize with one another’s situations. With a meeting, it becomes possible to discuss expectations, establish the requirements for samples and mockups, and illustrate outcomes and limitations. This can set up an inclusive environment where everyone on the construction team is dedicated to providing quality concrete work.

For Edmonton’s St. Joseph Seminary, a white, continuous pour concrete wall showing case inset for placement of the stations-of-the-cross. Concrete formwork professionals will know maintaining square edges and no voids on the underside of the formwork is difficult to achieve. Ports were used here to vent air as concrete was places, and hand vibrators on the formwork to ‘persuade’ the concrete to fill voids.

Case study: St. Joseph Seminary
Edmonton’s St. Joseph Seminary was opened in 2010, after the existing seminary lands were annexed by the provincial government to allow expansion of the St. Albert Trail and Anthony Henday Ring Road. The chapel component was modelled on the floorplan and shape of ancient Roman basilicas, with a direction from the Bishop of the Edmonton Archdiocese for a permanent structure reflecting the history of the Catholic Church and the permanence of the religion for future generations.

With that in mind, the chapel is formed from one of the largest installations of white self-consolidating, self-levelling concrete in North America. This concrete was cast as a single pour, using four pump trucks and two standby pumps in a continuous operation lasting almost 36 hours. The walls are 11 m (36 ft) high by 450 mm (18 in.) thick, and supported by falsework and custom-fabricated formwork.

The success of the AESC was directly attributable to establishing early communications between the concrete supplier, formwork fabricator, concrete placers, construction manager, and the architects and engineers with DIALOG (the design firm for the project). The members of the construction team were brought together a year in advance of any concrete being placed to discuss conditions that could affect its placement and appearance.

Everything that could have an effect on the final outcome was put on the table for discussion, including:

The concrete supplier cleaned out its storage silos to control the appearance of the concrete and ensure the aggregates and cement were consistent in colour and appearance throughout the mixing and placing operations. The construction manager co-ordinated all trades immediately affected by concrete placement, as well as those responsible for subsequent work associated with part of the finished appearance (e.g. stained glass windows, electrical lighting, sculpting).

Once all contributing trades and design team members had compiled a list of controllable criteria, the project specification was written to capture the various procedures and quality control mechanisms. Describing the work results involved the concerted efforts of the structural engineers, design architects, and contract administrators, so each discipline was aware of the consequences for enforcing the performance requirements associated with materials and workmanship.

Several sample installations of the concrete mix were tested during installation of other concrete components, and were well-hidden within elevator shafts and basement walls. Mockups were created and used as part of the final site signage, all in an effort to show repeatability and that the specified quality controls provided a consistent concrete appearance at each different installation.

Even with the amount of control effort, there were still surprises, such as a sudden cold snap and late-season snowstorm that dramatically altered the environmental conditions, and which could have greatly affected the appearance of the exposed concrete. The construction manager had insulated blankets and heaters on standby, which were almost deleted from the specifications because of the time of year (April to May). A lot of tension and sleepless nights resulted after the concrete trucks had departed, since the final esthetic finish could not be determined until the forms were removed seven days after completion of the pour. The whole team was elated to see the concrete in its pristine form—a resounding success.

The only condition the team failed to describe—and which subsequently almost ruined the material’s final appearance—was the concrete worker that patched and repaired bug holes and voids in the surface using standard cement-based mortar. The concrete specification failed to reference the same white cement and titanium oxide colour admixtures used in the concrete mix, resulting in very visible grey smears and spots. Fortunately, this ended up being in an area invisible in the final installation.

To paraphrase Robert Burns, the best-laid plans of mice and men often go awry. No matter how carefully a project is planned, something may still go wrong, so the more the project parameters are discussed and communicated to an educated and trained team, the better controls can be put in place to offset the unknown.


Chris Bennett, CSI, is a concrete consultant for commercial projects in North America. He specializes in document creation, contractor training and technology testing for MasterFormat Divisions 03, 07, and 09. He can be reached via e-mail at[7].




[8]Keith Robinson, FCSC, FCSI, RSW, LEED AP, has worked as a specifications writer since 1981, and is an associate at DIALOG in Edmonton. A past-president of Construction Specifications Canada’s (CSC’s) executive council, he sits on several standards review committees for ASTM and the National Fire Protection Association (NFPA). Robinson works closely with the Concrete Floor Contractors Association (CFCA) to address specification requirements for floor flatness and levelness. He is a member of the editorial advisory board of Construction Canada. Robinson can be reached via e-mail at[9].


Rae Taylor, PhD, holds a doctorate in civil engineering and materials science from the University of Leeds, and a post-graduate certificate in technology management from the Open University. Her principal research interests lie in the field of materials science and improving the environmental impact of construction materials, with a focus on the effect of cement replacement materials and additives on cement microstructure. Taylor has published on the topic of cement in numerous academic journals and conferences, such as the Journal of the American Ceramic Society, American Mineralogist, and Cement and Concrete Research. She can be reached at[10].

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