An Artful Concrete Wall in the Making
We had some fun with a concrete wall that we created for a modern home makeover. We changed the look of the house by designing and applying a new siding and a metal roof. With it came a new color and modern lighting scheme .
The biggest punch, however, in transforming this 70’s style house into a modern dwelling comes from a new entry area. It is designed around a transformed engagement in the approach to the front door and the front door itself. The ensemble includes a butterfly roof, a carbon steel and wood structure, stainless steel cable rails, a one-of-a-kind kiss ass special engineered 7’x7’ rotating pivot door (details soon to come), and a set of concrete walls.
At this stage of the game we were dealing with the two cast-in-place concrete walls and found both, our clients and our concrete crew, to be amiable for some extra attention.
The general design was set, that is the size, proportions, and situation, as well as its spatial engagement with the house and the approach sequence. We wanted to seize the opportunity and insure a truly beautiful and artful constructional expression, however.
Besides taking measures to create a smooth, nearly polished finish, we played with the color of the concrete and the form itself. As far as the color is concerned we simply used an integrated color pigment that was added to the concrete mixture at the concrete plant. We went with “Davis Colors” and choose a dark charcoal grey out of their color palette. The slurry arrived almost black on the site. As we took off the formwork it had already grayed out. We will see what the curing process will do during the next month. After that we are planning to seal it with a clear concrete sealant to give it the final shiny wet look that we are after.
As for the formwork? - This is where we really got to have some fun. Our intention was to create a crevasse, an oversized stylized fissure into the taller of the two walls. This one is a 5’ wide and 12’ tall freestanding slab. It is just 9 inches thick. It’s a tall, unnerving piece that brings the entry into scale and dramatizes the approach to the front door as it squeezes you between itself and the house.
To create the “crack” we had to modify the formwork. Here are some of the steps we took:
Read all our “dialect’s musings” feeds here:
After some initial sketches we started with testing out several different methods to create an inverted crevasse, a hump, if you will. It had to be sturdy to resist the forces of the concrete, but flexible to be able to be removed after the pour. It had to withhold the chemical reactions of the concrete. And we had to be able to shape it to a form we liked.
We settled on this path. (Sorry for the rough sketch. We jotted it down in the field) We did modify it a bit when we executed it. We used double-sided duct tape to hold the plastic to the Styrofoam and omitted the tape on the bottom.
Here you can see the “hump” after we stacked four 3/4” thick layers of Styrofoam and were starting the cutting and melting process to create the perfect shape. The first layer is screwed down and glued. The top three layers are just glued with Styrofoam glue.
Double sided duct-tape.
6 mil plastic tarp, cut on the bottom edges and siliconed.
Here you can see the guys from Borek’s Concrete hard at work. The form had been erected the previous day. They moved the concrete by the bucket to reduce the force of the concrete hitting the formwork and avoid the havoc a pump would have created. Our “crack” is on the front panel going all the way from the very bottom to the very top. The buckets turned literally black by the wet concrete with its grey pigment integrated color add-mixture.
After a few days of curing we removed the formwork. Our Styrofoam “hump” came out beautifully. It helped to be able to scrape out the foam. The 6 mil plastic then disengaged form the concrete like a charm.
As for the crevasse - We were speechless. Just perfect. The rectangular pieces on the top are forms that will be removed next. They will leave rectangular gaps that will engage with trellis rafters towards the house.
Both the fissure and the color are just drop-dead gorgeous. As mentioned, the final touch is going to be a clear sealant that will turn this slab into wet dark mysterious piece of pure sexy! ;)
