That's supposed to be "mantle" which I am sure you know, LOL!

I don't know if this is what you are looking for, but my mantle hood is 48" wide and the vent insert is also sized for 48". However, it is not as deep front to back and there are wood "filler" pieces that cover any places where the vent insert does not fully meet up with the sides of the wood surround. I purchased my vent because the cabinet maker made this particular surround to work seamlessly with it, but I am sure that it would be an easy modification. Also, the wood surround is made to hang several inches below the vent insert, so that any of these gaps and fillers are not visable unless you bend down and look under it.

Yes, that's what I need to see. That looks nice!

I do have the extra space on the sides, but you have given me some food for thought on how to finish this out!

Thx!

Unless the insert is already substantially larger in both width and depth than the cooktop or range it covers, wood should ABSOLUTELY NEVER EVER be used as spacers to make the insert fit the mantle. That's a fire hazard! If your insert isn't large enough, then you need to get a custom metal fabricator involved. If all you need is a small spacer, then you probably don't need a fabricator, but it does need to be metal and not wood.

Westiegirl, from your pic, I can't tell if there's only metal directly above the range surface, but if any wood part is above that range surface, you need to address that ASAP.

Live_wire_oak thanks for pointing out the safety info for range hoods. Mine is not installed yet, but I see my cabinet maker gave me wood inserts to use use when mounting the vent. When they are installing it, I will see if the placement calls for metal instead. Better safe than sorry.

Live wire oak, is the rule that there should be no wood directly above the cooktop? The edges of our mantel are above the cooktop (at the front) and are wood, about a half inch thick.