Since I 'am a nubie I have another question . Can you build a hearth without having 1" of air space between the non combustible material . I have an existing pellet stove I will replace with a wood stove . Where the stove will sit and the existing hole for chimney there will be a problem with clearance to a combustible wall. Is it legal to go with durarock and let's say slate without a 1" air gap. Thanks in advance for info