Biochar Roof Tiles
Biochar based roof tiles were developed by students at Rochester Institute of Technology (project summary here). The team was tasked with coming up with a tile design as well as a biochar-concrete recipe which could be tested on homes being built by the 4 Walls Project in El Sauce, Nicaragua. The recipe chosen for the current batch includes roughly 30% biochar by volume (10% by weight). Cement, sand and water make up most of the rest. This is an example of a Biocomposite.
A plastic mold was created for the tiles with a wood-like finish on the sunny side of the roof. Current cost estimates put the entire roof at less than half the price of the zinc roof. Although a realistic price on biochar has yet to be assessed, the amount of char needed could likely be made in one day using 1 or 2 Kon-Tiki soil kilns so in a place like Nicaragua where the cost of labor can be as low as $5/day, the cost of biochar would be negligible.
Not only could these biochar cement roofs be cheaper (see comparison of different roofing materials and their costs, weights and other properties here), but all indications are that they will be quieter and will help reduce heat gain as well. That’s a sustainability trifecta as far as I can tell: People get more sleep due to less heat and noise; on the profit side homes will cost less and local jobs can be created; and the planet benefits from reduced mining for zinc, less waste from plastic bottles and up to ½ ton of CO2 gets sequestered in a single roof!
Text shortened from original location: Finger Lakes Biochar: "Could biochar roof tiles be coming soon to a roof near you?"