By installing a set of glass doors on your fireplace, you will not only enhance its look but also offer a measure of safety by keeping burning embers from flying out and onto your floor. You will also enjoy a fire in your fireplace unobstructed by a conventional metal chain screen, while still receiving warmth through the tempered glass.
Lean your glass door assembly against a wall with the front side facing the wall. Place a protective cloth between the doors and the wall. Remove any factory-installed door stops used for shipping purposes. Install the strips of fibreglass insulation to the inside of the door frame. Trim the fibreglass strips with scissors so they will fit snugly in the inside of the door frame.
Attach the four mounting brackets to the inside of the door frame assembly, two on the top and two on the bottom using the provided hardware and tighten finger-tight. Some fireplace screens may have adjustable upper mounting brackets that need to be assembled before being attached to the frame. Check the installation directions that came with your screen.
Move the screen assembly to the fireplace opening with the brackets facing inward. Make sure the frame of the screen completely covers the opening with no gaps and that the mounting brackets are inside the opening.
Push the fireplace screen frame so that it is flush against the front surface of the fireplace and have a helper hold it into place. Open the doors and reach inside to the upper mounting brackets. Position each upper bracket so that it grips the upper metal lintel bar at the top of your fireplace opening. Tighten all of the mounting screws on the upper brackets with an adjustable wrench in a clockwise direction.
Position the lower mounting brackets at the bottom of the screen until they lay flat on the floor on the inside of the fireplace. Mark the mounting holes with a pencil and position the brackets out of the way. Insert a 5/16-inch masonry bit into an electric drill and bore a 2-inch deep hole over each pencil mark into the fireplace floor.
Tap a 10-14 x 1 lead anchor into each drilled hole with a hammer until it is flush with the surface of the fireplace floor. Position the bottom mounting brackets back over the anchors and insert a #14 x 1 ¼-inch bolt into each anchor. Tighten each bolt with an adjustable wrench in a clockwise direction. Tighten the remaining bolts that attach the brackets to the screen in a like manner.
Use a putty knife and stuff any insulation that may have squeezed out between the fireplace screen frame and the front surface of the fireplace back into the frame so that it is hidden from view.