Clay and Plants
Interdisciplinary work in Landscape Architecture:
Our professor, Richard Hindle gave us the artistic license to incorporate our personal interests into this green-roof studio. We took the idea and ran to the University of Oregonʼs Ceramic studio. Through the term, we learned a tremendous amount by designing and building a unique green-roof system that we will be share with the community for years to come.
Introduction to the ceramics studio:
The resources and helpful hands at the Ceramic studio allowed us to build and fire more than 50 stunning tiles in about four weeks time. The extruder pumped out around 250 lb. of clay in the form that we needed our tiles to be.We became masters of a skill that is used to connect two pieces of clay together called slipping and scoring.
The slipping and scoring process includes a tool with the ability to scratch the surface of wet to semi-dry clay, slip (slurry clay, you can find it at the bottom of your clay bucket while throwing on a wheel) applied to the scratched area, and the act of “shimmying” or pressing the two pieces together.
Each ceramic piece was scratched and slipped; the tiles; due to the size of the extruder, the Kawara or end cap, and the sunflower. Ceramics takes a lot of attention to detail, we spent many long hours propping the tiles to keep their shape, waiting for them to dry to scratch and slip them or hurrying to connect them before they were too dry. Many considerations must be taken into account when dealing with a large project such as our green-roof. For example, we had to make many parts of the ceramic roof at the same time because they must be at the same consistency to avoid cracking and different shrinkage rates. Something we did overlook was the shrinkage of the tile as a whole through the firing stages. We designed the wooden roof structure holding the ceramic tiles to the width of eight clay tiles. However, when we manufactured the tiles, we measured them to a known dimension, wet; not taking the firing shrinkage into consideration. Consequently, after the firing process, we were left with a small uncovered portion on the right side of the roof. Overall, the attention to detail paid off and our roof is a success.
The kiln that fired our 50+ tiles is named Olsen. This large gas kiln helped us make the ceramic tiles with no losses or damage. It was the first time for any of us to experience the world of the kiln. The first firing is called bisque. After shaping the tiles and letting them dry, we loaded the kiln.Cheri, a friend who has experience in the ceramic lab extended her time to help us (thank you Cheri!) fire our tiles. We candled the kiln allowing the atmosphere and the clay to reach an even and warm temperature for six hours.
The firing took another six hours and the entire process consisted of a sixteen hour day in studio. Although it was intense, the knowledge that was gained is something to be grateful for. Olsenʼs temperature was gauged by taking out one of two brick pieces from peep holes.
After blowing in the kiln to reduce smoke, small cones of clay that melt at different temperature were analyzed. Our red terracotta clay body melts at cone 06 temperature; therefore, when the cone before cone 06 melts, we know that the kiln is at the proper temperature (around 1800 degrees) and we may turn off the kiln.
After the bisque firing, we then glazed the tiles using a clear glaze. First, portions of the tiles that will be in contact with the kiln are waxed to prevent glaze from sticking to the tile and kiln board. Next, the tiles are evenly coated with glaze. The clear glaze mixture is a green color prior to being fired. Once glazed, the kiln was loaded up again for a second firing. We had made extra tiles to allow for loss and breakage in the two firings. However, we were incredibly lucky to not break a single tile. We opened the kiln for the final time and were rewarded with a full kiln of unbroken and beautiful tiles.
Roof Frame Construction:
The wooden add-on roof frame is a fairly simple, yet elegant construction plan. We started by making all necessary cuts using a cut list. Constructed at a 4/12 ratio the supports were cut to fit the space exactly.
All four 2x6 supports are lag screwed into the 2x4 studs which are in turn, bolted through the metal ribs of the storage container. Prior to installing the tiles, we all hung off of the roof to verify that it would hold the weight of the tiles/soil/plants (approximately 150 lbs.)
The roof surface was prepped with #30 roofing felt; 1x2 inch nailing strips were then installed horizontally on top of the felt. Each tile was screwed to the strip at the top of the tile through a hole that was created while the tile was still soft and before firing.
The decorative end cap was designed to be attached using screws. However, the shrinkage from firing made our pre-drilled holes for the end caps not line up properly with the eave tiles. This was remedied with innovative thinking and the use of sturdy wiring.
Each tile is designed to interlock to the tiles on its left and right. The installation process was very much like a giant ceramic jigsaw puzzle; many pieces had to be swapped in and out to find the perfect fit. We truly came to appreciate the technical specificity involved in large scale manufacturing that results in consistently perfect tiles.
As part of the shrinkage issue, the gables needed two inches of clay removed on the outside of the tile to allow the tiles to sit on each other when they overlapped the roof. We cut the tiles using a makeshift wet-saw: a Dremel and water bottles. By cutting a small piece off of the gable tiles, we were able to mostly span the gap.
The final step in finishing our green roof was plant installation. The growing medium used is a 75% mineral 25% organic mixture. This mixture reduces the weight dramatically compared to a typical potting mix with high organic matter. Drought tolerant plants were chosen due to the small volume of growing medium, the minimal availability of water and desire to create a sustainable structure. We planted Hens & Chicks, Rosemary, Creeping Thyme varieties, Sage, Blue Fescue, Ajuga, Ice plant and a variety of sedums.
We hope that you have enjoyed learning about our roof fabricating/building process as much as we enjoyed doing it. We hope that we will have future opportunities to design and create something this beautiful again soon.
Rich: Thank you for the opportunity, instruction and support that you gave us. We couldn't have accomplished something as ambitious as this without your instruction.
CCHHIICCAAGGOOSS 3: 44 - *POSTSCRIPT #1:* The broad—cast has been Mediumified and can be found here. Added at the end is a map of our stops and a simplified route. (18 September ...