Insulating under grate?

[chicken123]

Is it necessary to insulate below the grate?

[Schiefe4]

No its not. Heat rises and you are trying to retain (by insulating) the heat from the fire. The area under the grates is for draft and ash collection.

[chicken123]

Thank you!

[Daves Maple Farm]

We have a wood floor so we did insulate under the firebox. Used fire board, covered it with a sheet of heavy stainless and over layed with fire brick...a.bit over kill but we had the material.