Tag Archives: Cob

School Bus Stop Cob Bench

Last week we wrapped up the cob school bus stop bench in Arvada that we built in the spring. we gave it a quick coat of lime plaster to protect it this winter, and plan on coming back to do a finer finish next spring.

We are considering making the final coat a tadelakt – a traditional Moroccan water-resistant style of lime finishing. At the work party we tried out tadelakt samples on AAC – Aerated Autoclaved Concrete. They worked great and volunteers got a chance to learn about the process and science behind creating this shiny and smooth finish, plus a small tadelakt tile to take home.

For this coat, we hand mixed a small batch of lime plaster, using a combination of Type S lime and NHL (Natural Hydraulic Lime). The NHL helps to make the curing time faster, which is ideal when plastering late in the season when frosty overnight temperatures might arrive anytime.  Ideally, this coat will have at least a week of frost-free nights as it cures for the best durability.

This coat went on quickly. After wetting down the bench, we hand applied a layer then used sponge floats to roughen up the surface so water won’t erode it as easily. Extra lime plaster was recycled into the soil around the base of the bench as a temporary weed barrier.


Thanks to everyone who made it out! We’re feeling great about this project and hope that it gets use by neighbors and children while waiting for their morning bus.

mixing lime plaster

Mixing the lime plaster with a mortar hoe in a wheelbarrow. For small batches this is very efficient.


Before bench

Before: lime stabilized clay base coat plaster.





bench after lime plaster

After: a light yellow sponge coated lime plaster finish.

Woodbine Fall Festival

We’re participating in Woodbine’s Fall Festival this year to make some minor repairs to the cob bench that’s attached to the oven. Come up for a lunchtime potluck and seed saving lesson, followed by some learning about cob, plasters, and fixing up the bench.

Plaster Party

Join us for a work party at Tonita Young’s house. We’ll be plastering a cob bench school bus stop. We built the bench over Earth Day Weekend. Check out our post on the weekend for some great photos.

Earth Day Recap

Thanks to everyone who came by our table at Union Station as part of Denver’s Earth Day Celebration. We talked with a load of folks about natural building on the Front Range, baked an absurd amount of cookies in the Colorado Straw Bale Association’s solar oven, and had a fantastic time. Check out some of the photos below!

On Saturday & Sunday, we had a work party at Tonita Young’s home. We built a cob bench school bus stop that is now ready for plaster. After slinging all the cob, we had a delicious dinner with all of her neighbors followed by some street luging with the neighborhood kids! Photos below and info on the bench plaster party here.


Winter Cob Stomp

There are some crazy folks here on the Front Range. Well maybe not crazy, but certainly passionate about natural building. Avery Ellis, of Backyard Revolutions, and Mike Wird of Earthship Denver organized a Cob Stomping Party this past Sunday in order to finish a Rocket Mass Heater they have been building over the past two months. Despite the chilly February weather over 25 folks showed up to get their hands dirty. In addition to mixing mud all day, there was quite the buffet of delicious home cooked food. I’ll let the photos tell the rest of the story…