Processed Concrete Floors in Renovations

Durable | Sustainable | Beautiful

Architects have been enamored of concrete’s beauty for a very long time; the general public - not so much. Never mind that Pliny the Elder praised the virtues of Roman “Opus caementum” in monumental constructions of the 1st century CE, “It looks unfinished” was a typical lament of the consumer of the vernacular, particularly up until the turn of the 21st century. Then came finishing techniques, densifiers and sealers that made concrete counters, tabletops, and floors chic, if only because their finishes afforded them looks that were less like concrete and more like stone.

Today, contractors can transform a once-utilitarian factory floor into a dramatic walking surface for lobbies and lofts. With a substantial history of successful adaptive re-use projects, the architectural team at Trivers Associates specifies the latest in proven techniques and materials to leverage the value potential of century-old concrete slabs into distinctive designs.

“Concrete Polishing” is commonly used to refer to changing an existing concrete surface by means of a mechanical process involving cutting and/or refining the surface to a desired finish. However, the correct terminology is “Concrete Processing,” as not all processed concrete can be called “polished” (if, for example, only Grinding and Honing steps are undertaken).

There are three fundamental visual aspects of a processed concrete floor finish – surface cut (i.e. degree of aggregate exposure), reflection (degree of polish), and enhancements, if any (stains, dyes, saw-cut patterns).

Finishing levels - basic, medium and premium - drive the amount of work entailed, both in terms of aggregate exposure and reflection/sheen.

Basic-level grind-finish, Medium-level honed-finished, Premium-level polished 


Aggregate Exposure Class


frosario Class A cream exposure
Class A- Cream Exposure

Class B- Fine Aggregate Exposure
Class B- Fine Aggregate (Salt & Pepper) Exposure

Class C - Medium Aggregate Exposure
Class C- Medium Aggregate Exposure

Class D Large Aggregate Exposure
Class D- Large Aggregate Exposure


Gloss Levels


Densifiers are water-based chemical solutions that first work by penetrating into the surface of the concrete and reacting with calcium hydroxide to produce calcium silicate hydrate (CSH). The CSH that is produced fills the open pores of the concrete, increasing its density. The three types of densifier most commonly used are- sodium, potassium, and lithium. Lithium-silicates penetrate without scrubbing or adding large amounts of water. This saves time, money and energy. They also penetrate completely, which eliminates flushing, waste containment, collection, and disposal—and their costs.

Variables within a concrete processing contractor’s control:

    Weight, RPMs, speed at which machine moves over surface in a linear motion.
    Configuration of diamonds’ face/tread
    Saturation of diamond grit in the bonding
    Hardness of diamond bonding
    Point at which operators switch abrasives
    When applied
    What type
Physical grinding, honing, and polishing
    Degree to which the concrete surface is cut
    Level of clarity of the cut surface
    Refinement of the concrete from one grit to the next
    How well the floor is cleaned between each grit adhesive

Variables of Existing Conditions not within a processing concrete contractor’s control:

Concrete Surface
    Imperfections that need to be removed
    Surface flatness and levelness
    Presence of coatings, glues or mastics
    Finish: hand-troweled or mechanically-troweled
Concrete Mix Design

Going forward, exposing and processing existing concrete floor slabs will increasingly be among the most popular value-added choices available in adaptive re-use buildings. Trivers Associates stands committed to delivering current and reliable specifications and detailing of this environmentally responsible process.

An Introduction to Concrete Processing
A Quick Guide to Polishing Concrete Floors
Polished Concrete Information and Options
Levels of Concrete Polishing 
Technical Resources for the Concrete Industry
Concrete Polishing Association of America (CPAA)

Published by Frank Rosario, AIA, Project Manager 

Raising the Bar

In a profession proliferated with aggressive deadlines and strict budgets, it can be easy to let one’s love of design fade. One becomes consumed with staying within budgets and parameters, meeting codes, and designing under pressure with limited time.

There is an interesting transition that happens from the university to the professional level. During studio there is a freedom that transcends any budget or code. And as for deadlines, well, you don’t sleep if you have to. Design happens in iteration after iteration with countless meetings with professors and peer reviews. You have an entire semester to explore options and perfect your design.

But in the profession, time is money and dictates how much of it we can spend on a project. When reality sits in, it is easy to get stuck in a box, to design the normal, and to forget what it is like to invent the extraordinary.

At Trivers, we do a great job of coming up with intriguing concepts and pushing boundaries. We consistently challenge ourselves. If, due to the constraints of assumed practicality, our ideas do not flourish as we had hoped, we can still say that we put our best foot forward and pressed for something new, different, and exciting. Our clients know that they are not only working with Design Professionals, but with passionate individuals who deeply care about what they do.

So how does one continue pushing to keep their love of design alive outside of the normal work day, and fight against the restrictions of normality that can infect the spirit with complacency and mediocrity?

There are a plethora of design expressions in our profession. Every person is unique in how they keep their design vigor alive. Some renovate personal property or flip houses. Others obsess over precedents or read extensively. Whatever keeps that passion going, keep doing it! It is those interests outside of work that help to fuel our drive within the profession and push against normality.

For me, I like to design for fun. When office tasks focus on construction documents, reviewing submittals, taking meeting minutes, and consultant document coordination, a creative spark ignites in my soul that comes to life when I am home. The desire to create must be met one way or another.

Below are a couple of projects I have worked on as a hobby. The first is the Double-Bar House, which inspired the deliciously cheesy double-meaning of the title “Raising the Bar.”


Both projects are a “double-bar” concept. This house is a single floor with a living space bar and a bedroom bar. Between the shifting bars is a reflecting pool and a swimming pool. The reflecting pool serves as a more intimate space at the back of the house while the pool serves as the centerpiece to the more public entertaining portion of the house.


The second house consists of two stacked bars delved into the face of a cliff. Below is the living space and entry while above are the bedrooms and a carved outdoor space.


The screen gives the home dweller an ever-changing view of the landscape. From an angle, the extended mullions shield the view, especially where they are more dense in the variation of the design, while directly on one can see clearly out.


The screen consists of corten and wood panels, which complement the exposed stone and help the structure blend in with the façade.


The conception of these projects brings me simple joy and keeps my creative spirit alive. They remind me of why I chose Architecture; because I love to design. Keeping that interest alive is crucial for all of us. Remember why you chose this profession, and keep the spirit alive that created all of those wacky, impractical, but absolutely wonderful things at the university.

If we do not raise the bar for intriguing, quality design, who will?

So keep raising the bar and raise it high. Let the passion that lured you into architecture stay alive, brilliant, and beautiful.

Posted by Matthew Skinner, Architectural Designer

One Plus: St. Louis ArtWorks

My dad once told me that he became a civil engineer because he wanted to help make the world a better place to live. I’ve never forgotten that and have tried to use my career as an architect in the same way.

I initially heard about St. Louis ArtWorks (SLAW) from one of the other Principals at Trivers, Joel Fuoss. At the time, he was the Board Chair of the organization. I had been frustrated for years by the lack of awareness that some young people have about good opportunities; opportunities to be active in the community, opportunities to express themselves, opportunities to earn money, or opportunities to earn the respect of others. It has always been obvious to me that we’re all born into different situations, and that at an early age a little support and exposure to better opportunities is all some people need to really thrive.

I met Priscilla Block, the Executive Director of SLAW, while we were both participating in Leadership St. Louis. Our discussions led me to believe the organization provided much of what I mentioned above. The mission of St. Louis ArtWorks is to broaden educational and career opportunities for youth in the St. Louis Region through apprenticeships in the arts through community collaborations. They strive to create positive educational opportunities for youth through paid artist apprenticeships. While participating in the program, students also learn business and social skills through partnerships with professional artists in a variety of media. Eventually, Priscilla asked me to join their Board of Directors, and I gladly accepted.

When I joined the Board, one of the first issues to be dealt with was the need to find a new home for SLAW. At the time, they had space in the Centene Center for Arts and Education in Grand Center, as well as a satellite location in a storefront in the Old North neighborhood. Both were good locations, but the spaces were too small for the growing organization. Additionally, despite some synergy with the other arts organizations in Centene, SLAW’s program often didn’t fit in well. High school students who are creating art are sometimes noisy, and usually messy. With the end of the lease approaching, the Board made the decision to start the process of finding a new space.

People often talk about offering time, talent, and treasure to a worthy cause, and that is exactly what Joel and I decided to do. A committee was formed and we developed a program for the new space in order to better focus our search. In addition to the spatial requirements, which were easily understood, we also thought a lot about where this new home should be located. The main priorities included accessibility for the people who participate (near mass transit and geographically close), and visibility for the people who support the operation. The Delmar Loop area emerged as a strong candidate. When the building at 5959 Delmar became available, we realized it fit our program very well. It was being used only for storage and had been an industrial building throughout its life, but the large spaces, generous daylighting, and durable nature of the construction were perfect for SLAW activities. The Board and Priscilla moved quickly and a lease was negotiated.


5959 Delmar- Interior Before Renovation 


5959 Delmar- Exterior Before Renovation 

About this time Trivers joined “The 1%” (now known as “The 1+”) and committed to donating at least 1% of our time annually to non-profits that needed design expertise. We easily chose SLAW as our first recipient and completed the construction documents for the buildout of the new space at no cost to the organization. We assisted with bidding, applied for the permits, and negotiated the award of the project to Raineri Construction. They proved to be a tremendous ally by understanding the mission of the organization and by helping make what seemed to be an impossibly low budget work for the project. We relied on many favors, a lot of donated time - which included a lot of “sweat equity” from the Board - and donated materials to get the project done. There was also a “Hard-Hat Breakfast” fundraiser during the construction process that raised additional, much needed, funds.


Board Members and their families pitched in to help paint

Today SLAW has a new home and continues to expand their programs allowing more young people to have the opportunities they deserve. In November 2016, St. Louis ArtWorks received the 2016 National Arts and Humanities Youth Program Award, which was given during a special ceremony hosted by then First Lady Michelle Obama. This well-deserved award is the product of St. Louis ArtWorks’ continued commitment to growing their programs and empowering youth through the arts.


Apprentices working in the new space


Mayor Slay's visit 

As the pilot project for our 1+ commitment, I can’t think of better outcome. We are actively considering our next endeavor and look forward to hearing all the great stories from the alums of St. Louis ArtWorks. You can learn more about SLAW by visiting their website.


5959 Delmar- Exterior Today


Posted by Joe Brinkmann, AIA, Principal 

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