hearth wall ?

[tarzan]

When building a hearth with a 1" air gap does it need to be completely open between the combustible and non-combustible wall or can there be a set amount of opening at the bottom and top for air circulation?

 

[begreen]

Basically the wall shield needs to be 1" off the combustible wall, have at least a 1" air gap at the bottom and open on the top. The objective is to make it so that air convects behind it easily. You could continue brick or stone down between studs to mimic feet and you could put a cap or stone mantel on top, as long as the cavities between the studs are allowed to vent easily. Does that answer your question?

 

[tarzan]

Not sure. If I were to build the hearth using 1/2" cement board and tile spaced 1" off combustible drywall could I then leave an air gap of say 1"x4" on bottom corner and same gap on opposite top corner or should bottom and top be left completely open?