TreeHugger has always been an advocate of creative architecture that uses local, sustainable materials. While we're usually talking about everything from skyscrapers to hobbit houses, the principles apply just as much to playhouses. That's why we love this entrant in the Green Design Contest on Instructables.
The creator, ghettocottage, writes:
Here in Central California summers are very hot and dry. Being outside can be uncomfortable, so we wanted to create a naturally cool (cool as in temperature) area for our son. Since the ground here is full of clay, we thought a cob layer on a playhouse with a living-roof would provide sufficient cooling...and it works! This play area is one of the coolest spots on the property during the blistering hot summer heat. It also stays bone-dry inside during the winter.
Since I used scrap-wood and earth already available to me, I only had to purchase a few items. Total Cost: $30.00
The instructable focuses on how to do the cob part of the playhouse, from creating the moisture barrier to applying the mud. The entire construction can be something the kids are involved in (especially the mud part!) to make the playhouse entertaining and education from the very beginning.
"This structure has held up fine for one year. It lasted through winter rains, and 2012 hottest summer on record. Inside the house is cool and dry. The little porch has play-sand (mixed with rounded-smooth river stones to discourage cats but still be comfortable on little bare feet). [T]he end result is a huge amount of thermal mass that easily absorbs that summer heat, and provides a comfortable place to play for the kids."
We love it!