After grumbling about a couple of recent Bloganuary prompts, I’m pleased to acknowledge a provocative question today. In contextualizing the prompt with respect to life at Rosslyn, I will weigh focus on past or future and will propose two distinct, dissimilar conclusions.
Do you spend more time thinking about the future or the past? Why?
In responding, it’s tempting to exercise a subtle kind of judgment with respect to focusing backward versus focusing forward. There’s a pejorative implication in focusing backward, I think. This seems to be especially true when thinking about the past eclipses thinking about the present and future. There’s an interesting debate to be had, but I’ll bypass it for another time.
Instead, in the case of my relationship with Rosslyn across these past seventeen years, I’d like to offer at the outset that my answer(s) to the question are dynamic, evolving over time. Rosslyn is an historic property in an historic village on the historic register. Lots. Of. Past. But our relationship with Rosslyn has been forward looking (thinking of the future) since day one.
If you’ve been with me for any time at all you’re well aware that Rosslyn, the property around which this multimodal inquiry circumnavigates like a drunken sailor, is rooted in the past… Starting out in the early 1800’s and spanning almost exactly two centuries.
(Source: The Past Lives On)
Our slooow rolling (metered, inquisitive, and often humbling) approach to rehabilitating this historic property hinged upon its architectural heritage, historic design elements, and archaic construction techniques. Virtually every step of the way — endeavoring to understand what this property needed in order for us to ensure a robust and enduring future worthy of Rosslyn’s legacy — required deep diving into the past.
In other words, thinking about the future of this property demanded intensive study of its past: four remaining buildings, property grounds, architectural DNA, original construction methods, etc. Restore Rosslyn’s past to create her future.
Past: Lime Putty
By way of example, let’s consider Rosslyn’s masonry. The home is constructed of brick. The foundations of the home, the carriage barn, and the icehouse are all constructed of locally quarried limestone. Between the bricks and the limestone is mortar. Duh, right? Not so fast.
I discovered early on in our Rosslyn rehabilitation adventure, that the mortar used to bond stones and bricks in the early 1800s differed notably from the mortar used today.
Traditional natural lime putty mortar is a carbonating/drying type of mortar. Of all of the historic mortars available it is the softest, most flexible and breathable. Ideal use is for old soft bricks, soft stones, stuccoes, and plasters. Most structures built prior to 1900 use this mortar.
(Source: Natural Lime Putty Mortar)
In short, lime putty is a softer, more pliable, and more breathable forbear to the Portland cement mortar now ubiquitous.
Present: Portland Cement
Modern mortar is a mixture of Portland cement and sand. The addition of Portland cement to mortar, and eventually the elimination of lime altogether, resulted in stronger mortar. Much, MUCH stronger. In the case of old brick (softer than modern brick) and soft stone like limestone, a Portland cement mortar would be stronger and harder than the material it’s bonding together. This is a bad formula.
For those restoring a historic building built before 1930 it’s important to select the right mortar to avoid spalling bricks. When the selected mortar is harder than the brick it surrounds then the brick will become sacrificial and worn away rather than the mortar. A sign of impending disaster.
Mortar should always be softer than the brick it is paired with.
The more portland cement is added to any mortar the harder it gets, and the harder it gets the greater potential you have to damage brick.
(Source: Lime Mortar vs Portland Cement – The Craftsman Blog)
Learning about early 19th century masonry construction introduced me to lime putty, and this discovery has guided me ever since, ensuring an historic rehabilitation that improves rather than compromises the heritage we’ve been fortunate to inherit. This example of the past informing the future is one of countless ways that thinking about the past — rigorous research and careful consideration — empowered and continues to empower our Rosslyn restoration. It also offers a compelling bridge to the second idea that I’d like to explore today: biocement.
Future: Biocement
You may have read an interesting Fast Company article by Ted C. Fishman on December 10, 2023 titled, “Why biocement could become America’s next big bumper crop“.
Here’s the subhead.
Colorado-based Prometheus Materials and other emerging companies are developing new biocements that could help meet the world’s growing concrete demands and avert climate catastrophe.
— Ted C. Fishman, “Why biocement could become America’s next big bumper crop” (Source: Fast Company, December 10, 2023)
The lede showcases an exhibit at the Chicago Architecture Biennial called the Bio-Block Spiral.
The Bio-Block Spiral rises as a tight 15-foot-tall circle of concrete blocks outside the entrance to an office building that’s away from the action. Perhaps that’s because the wall’s chief creators aren’t artists. They’re bacteria. More specifically, cyanobacteria, aka blue-green algae, aka pond scum.
— Ted C. Fishman, “Why biocement could become America’s next big bumper crop” (Source: Fast Company, December 10, 2023)
Wait. What? Concrete blocks created from cyanobacteria?!
There are so many reasons this article is fascinating, including the eye-opening quantity of concrete used in construction all around the world, the rapidly accelerating need for more concrete construction in the years ahead, the adverse effect of manufacturing concrete, the innovative research being done into cementitious alternatives, and the wonder-fueling possibility of biotechnological advances addressing climate change concerns in such a monumental way. If any of this intrigues you, read the article. It’s eye-opening. And it offers a glimmer of hope in a space that is too often discouraging.
What about the blue-green algae?
The cyanobacteria has been cultivated, with the help of clever biotechnology, to make biocement. The gooey material is a carbon-absorbing alternative to Portland cement, the binder currently used to make nearly all of the world’s concrete. Portland cement is churned out from limestone fed into giant, fiery, fossil-fuel-hungry, carbon-spewing chemical plants and is the source of around 8 percent of the world’s climate-warming CO2 emissions.
The biocement that binds together the sand and stone in the concrete used in the Bio-Block Spiral, in contrast, is expressed by the cyanobacteria, which is farmed, like a tiny crop. Because cyanobacteria live and grow through photosynthesis, they absorb carbon rather than emit it. Concrete made with biocement instead of Portland cement flips it from climate toxin to climate tonic.
— Ted C. Fishman, “Why biocement could become America’s next big bumper crop” (Source: Fast Company, December 10, 2023)
Too good to be true? Perhaps. Perhaps not. I truly want to believe. The implications are breathtaking.
Billions of years ago, cyanobacteria figured out photosynthesis, and exhaled the oxygen that gave Earth a breathable atmosphere and enabled terrestrial life. Now it may save the atmosphere we’ve wrecked.
— Ted C. Fishman, “Why biocement could become America’s next big bumper crop” (Source: Fast Company, December 10, 2023)
So far we don’t have an opportunity to experiment with biocement at Rosslyn, but I’ll be following the science for sure. Perhaps when the time comes to downsize and invent a new home biotechnology in general and biocement in particular will underpin our construction plan.
Thinking About the Future
To this point, I’ve tried to enmesh, even blur, past and future with respect to Rosslyn. But my last 522 blog posts tell a slightly different story.
Above I referenced our relationship with Rosslyn over the past seventeen years. In the last few of those years, catalyzed in no small part by our experience during the pandemic, Susan and I have evolved our thinking. We’re in flux. This transition, more gradual and more delayed than we’d originally anticipated in 2006 when we decided to purchase Rosslyn, is in large part a shift toward the future. If the first decade and a half living at Rosslyn depended on studying the past to inform the present and future, we’re now focusing much more on the marriage of present and future. We’re living today but increasingly thinking about the future.
With that, I will yield this post to the future…
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