The Coop CellarAn old root cellar was uncovered when clearing the back of our property. The block wall had caved to the pressure of the earth behind it. It had been used as a burn-containment for brush and trash so it was 1/2 full (or 1/2 empty!). The dilemma of what to do with this divided my husband and I for several weeks. As an avid member of the BYC community and supervisor of an ever-expanding flock (gotta love chicken math) I immediately thought of renovation into a new coop. My husband voted to either remove the rubble or bury it. Looking back at the amount of work, I'm thinking he had the right idea...but don't tell him that!
The first step was to grab a shovel and empty the debris from inside as well as dig out the hillside behind it. We needed to push the block back into place then reinforce it. This took a lot of muscle power! Luckily a helpful and knowlegeable neighbor had some input on fixing the root cellar and lent us a jackhammer and some jacks.
Once the structure was sound and could double as a bomb-shelter, we added the roof. Our plan is to build a shed on top for extra storage and keep the chickens below. This means the "roof" over the cellar is built with more strength than it would need if it were just covering the birds. We used 2 x 10 joist and 3/4 plywood. We then covered it with ice and snow barrier which will be a nice flooring for inside a shed later and keep things dry until then. The inner dimensions are 8' X 10' and the height is just under 6' (perfect for me, a bit low for my husband). Raising the roof would have cost more in lumber and time. Since I'm the chicken keeper, the low head clearance is not an issue.
Hardware cloth was used to cover the openings, providing ventilation. An old exterior door was scavenged from the house for the entrance. The door had a large dog door cut into it which I thought I could utilize for letting the chickens in and out but that hasn't been tried as of yet. A large bank of nest boxes were installed with the intention that they would be accessible from the outside of the coop (I never use that feature) and the eggs would roll out to the front. I found that the birds did not like the roll out nests and started laying on the coop floor. Once I turned the nests back into a traditional style with shavings in each box, I haven't had a problem. Of course, I have 5 boxes and they all love to use just one. I used scavenged lumber scraps to make the nest boxes and roosts which helped keep the costs down.
While I don't suggest building a coop into a hillside is the best idea, I am pleased with how this turned out. I would like more ventilation and am working on a predator-proof screen door to accomplish this. The advantage of the subterranean bunker is that it stays temperate all the time. It is protected in the winter, as it is below the frost line. It remains cooler in summer and quite pleasant. I have had problems with heavy rains flooding in under the door, but improving the surrouding grading and drainage should fix that issue.
Additional plans for the future: gravity fed water and feed stored in the shed (to be built) above. Higher roosts for when I forget to close up the coop at dusk and the critters snatch the low roosting chickens.
Cost of construction:
Concrete reinforcement: $25
Ice and snow barrier: $20
hardware cloth: $12