It will tell you in the owner's manual. Do you have it? If you know the model number of the fireplace, post it here and I'll be happy to find the manual and interpret it for you.

Thank you I do have the owners manual but was not able to understand the clearance. The Model is Ascent Linear (tm) Series (BL46)

Donna,

I have reviewed the installation manual and it clearly states you cannot use a combustible material right around the opening. Read my notes beneath the excerpt below:

This diagram shows that a you must only use a non-combustible material around the fireplace in the area indicated. In addition, if you want the fireplace recessed within the non-combustible surround, it the material must not be more than 4" deep if it is within 4" of the opening. This would apply to a non-combustible mantel surround.

With that said, relatively new to the market is an Aluminum Shiplap material that can be installed right up to the fireplace opening, since aluminum is non-combustible. Here's how that might look:

I can provide this material for you. Here's a link: Aluminum Shiplap

Mockups By: Fireplace Treatments

Thank you so much for the feedback!