How to Block Up a Fireplace Between Fires

Examine the fireplace opening for any chipped mortar, broken bricks or other irregularities. Repair any damaged areas that affect the shape of the opening at the front of the fireplace. Depending on your particular fireplace, this may mean chiseling out a broken brick and replacing it with a new brick and some fresh mortar.

Measure the front opening of your fireplace. Select a glass fireplace door unit that fits the width and length of the opening. These units come in standard sizes, although you may need to order a custom-made size for an old or unique fireplace opening. Choose a glass fireplace door that matches your existing decor. These units come in a variety of styles and finishes, such as silver, brass and gold.

Follow the manufacturer’s instructions to install the brackets in the doors and mark the holes for the brackets against the firebox opening. Use a power drill and masonry bit to create the holes in the opening of your firebox for the door brackets, according to the instructions. Tap lead anchors into the holes with a hammer. These anchors will help hold the fireplace door frame firmly in place.

Finish assembling the fireplace door unit according to the manufacturer’s directions. Install the fiberglass insulation in the channels around the sides and top of the door unit. Hold the unit against the anchors and screw the brackets in place. Insert the tempered glass panels into the openings. Close the doors whenever the fire is not in use to help block off the fireplace opening and keep the cold chimney air from entering your home.