We have had a clay chimenia for almost ten years and it is ready to fire up again for the coming summer. There are a few things that you need to do to keep your chimenia going for a long time.
First you need to fill your chimenia with 50 lbs of sand in the bottom. Don't build fires directly on the clay surface.
Second, season your chimenia by building small fires at first. We built small fires at first gradually increasing the size for the first 15 fires. Now we build fires as large and hot as we want. It is not unusual to have a fire with flame rising above the top of the chimney.
Cover the chimenia to keep out rain and snow in the winter. If moisture is allowed to accumulate in the sand on the bottom it can freeze and expand breaking the chimenia.
We probably have at least 3 or 4 fires per week in our chimenia during the spring, summer, and fall. The chimenia stays on our deck through winter ice and snow, though we do cover it to protect it against the elements. During the spring, summer, and fall we do not cover it and only be sure the top is placed on the chimney when it is not in use.
I have seen times when we had a very hot fire going and were suddenly drenched with a downpour of rain. I used to worry that the cold rain water on the hot clay surface would cause cracking but it has never been a problem.
We do not have kids and that probably has helped the long life of our chimenia. Today the glazed surface of the chimenia is long gone leaving the clay red surface exposed, but our chimenia keeps on going. I must admit I never would have predicted it would last this long when we first got it, but now I believe that it will continue to keep going for many more years as long as nothing falls on it or knocks it over.
Jnelson