How to Install Marble Tile Pencil Molding Around the Fireplace

Mix non-sag latex modified thin-set mortar with water in a bucket, precisely following the manufacturer's directions.

Fill a grout bag with the thin-set mortar.

Squeeze the mortar bag to leave a narrow strip of thin-set mortar along the surface where the marble pencil tile molding will be laid, beginning nearest to the floor. Apply short 28- to 30-inch lines of mortar to prevent premature drying. Typically, pencil molding comes in 12-inch lengths.

Dip a flexible putty knife into the thin-set and apply a paper-thin coating to the unfinished side of the pencil molding.

Set the pencil molding into the thin-set and firmly press it into place.

Place a one-sixteenth-inch wedge or spacer at the edge of the pencil molding.

Apply a thin coat of thin-set to the unfinished side of the molding. Set the second section of pencil molding in place, tightly abutted to the first piece of molding and wedge or spacer. Press the pencil molding firmly in place and set a wedge or spacer at the end of the molding.

Continue to squeeze a 28- to 30-inch strip of mortar on the surface where molding will be laid, apply a paper-thin coat of thin-set to the molding and set it in place until the pencil molding frames the fireplace. Make cuts to the molding as necessary with a wet saw. Let the thin-set dry overnight.

Pull the wedges or spacers out from between the lengths of pencil molding by hand or with pliers.

Mix un-sanded grout with water in a small bucket. Scoop up the un-sanded grout with a rubber spatula. Spread the grout over the empty lines between the molding pieces, packing the grout tightly into the empty spaces.

Wipe the face of the pencil molding with a damp sponge to remove excess grout.