Fire Resistance

The best cement board solutions for stoves and fireplaces

Nov 27, 2023

Save installation time with two UL-listed cement board products from PermaBASE Building Products

There’s nothing like the cheer and camaraderie that arises from gathering family and friends around a warm fire on a cold winter night. In a home, a hotel or a restaurant, fireplace inserts and freestanding wood stoves can be the central design feature of a room. Whether it’s modern ceramic tile, sleek granite or rustic ledgestone veneer, the wall finishing around a fireplace insert or freestanding wood stove adds to the overall ambience.

Radiant heat from fireplace inserts and freestanding stoves requires careful consideration of building materials used in fireplace surrounds and wall heat shields. PermaBASE Building Products, LLC, an affiliate company of National Gypsum Company, manufactures two cement board products that are UL-listed for use in wall heat shields while also saving installation time on fireplace insert surrounds.

Appropriate materials for fireplace insert surrounds

Most pellet and gas fireplace inserts require a certain amount of clearance between the unit and combustible materials. For these types of inserts, the manufacturer typically provides guidance in the installation instructions. Clearances can range from 12" to 3', and the installation must also comply with local building and fire codes.

Traditional surround materials include brick or metal lath with a scratch coat of mortar as a base for tile or stone veneer. Both are time-consuming and messy, considering the mortar that needs to be mixed, applied and given time to cure.

PermaBASE® Cement Board
offers a simpler, cleaner way to install fireplace insert surrounds that saves installation time. The boards arrive ready to be installed, no jobsite preparation needed.

The benefits of using PermaBASE Cement Board on fireplace insert surrounds include:

  • Durability: Comes with a lifetime limited warranty for residential interior applications
  • Design flexibility: Ideal substrate for direct-applied veneers
  • Time savings: Lightweight and easy to cut for speedy installation
  • Less cleanup: Less mortar work means less mess

Why not use drywall in fireplace insert surrounds?

If you’re wondering whether you can use drywall in a fireplace insert surround, the answer is: No. While drywall is fire resistant and used in fire-rated wall and floor/ceiling assemblies, it is not rated for use in fireplace insert surrounds. Radiant heat from pellet or gas inserts dries the cover paper, which is combustible and can pose a fire hazard.

UL-listed cement board for use in heat shields for walls behind freestanding wood or pellet stoves

PermaBASE Building Products created a wall heat shield system that can be made of ½" PermaBASE or ½" PermaBASE PLUS® cement boards — both of which are listed by Underwriters Laboratories Inc. for use with UL-listed solid-fuel and fireplace stove. These cement boards have been tested according to the UL 1618 Standard for Safety for Wall Protectors, Floor Protectors, and Hearth Extensions.

Freestanding wood stoves radiate heat in all directions so the building code typically requires them to be placed a minimum of 36" from walls made of combustible materials, if no wall protection is installed. Using PermaBASE Cement Board as a wall protector in between the stove and the combustible wall materials allows you to shrink that distance by 40% or down to 14".

PermaBASE Heat Shield

How to install the PermaBASE Cement Board wall heat shield behind a wood stove:

  1. Cut 4"-wide furring strips from a full PermaBASE panel.
  2. Attach a double layer of furring strips to the wall studs.
  3. Install PermaBASE Cement Board panels over the furring strips on the studs at 8" on center, using cement board screws long enough to penetrate the stud a minimum of ¾".
  4. Leave a 3" gap at the ceiling and a 1" to 2" gap at the floor to create an air barrier between the cement board panel and the wall.
  5. Prefill joints with dry-set mortar followed by PermaBASE™ Cement Board Tape and level the joints.
  6. Apply noncombustible finishes such as ceramic tile, thin brick or stone directly to the cement board.

Download the full wall heat shield installation instructions.

Reduce fire risk with PermaBASE Cement Board

Whether you’re adding a fireplace insert during a living room renovation or figuring out how a freestanding wood stove fits into a space, PermaBASE Building Products has you covered.

Visit the PermaBASE Design & Resource Center to find the design tools you need for any type of project.