Solution 1.8 Insert
Installation and Operation Manual
33
If the extension of the masonry hearth is raised at least 4" from the floor protection, a non-
combustible material without an R factor is sufficient.
If non-combustible material floor protection needs to be added in front of and level with the hearth
extension of the masonry fireplace, an R factor equal to or greater than 1.00 is required.
The use of an R value is convenient when more than one material is going to be used in the hearth
extension to cover the combustible surface. This is because R values are additive, whereas K
values are not.