How to Repair a Stone Fireplace Hearth

What You'll Need
Rubber mallet
Replacement stones
Construction adhesive
Small flat pry bar

A stone fireplace hearth is essentially the face of your fireplace. Not only is it unsafe to use the fireplace with the hearth in disrepair, it also does not do anything toward making the home look aesthetically rich. Over time, the stone fireplace hearth can become chipped, cracked, discolored and stained. Replacing the entire hearth can cost a lot of money, especially when you merely have to replace the offensive stones. This project is one that you can do yourself, and this article will explain how to replace the stones in the stone fireplace hearth.

Step 1 – Remove the Damaged Stones

Removing the stones from the fireplace hearth can be challenging, because you do not want to damage the rest of the stones if at all possible. You will need a steady hand to do this correctly. Place the chisel along the grout line and gently tap it with a hammer. The grout will begin to chip away little by little. You need to remove all of the grout in order to remove the stones. Adhesive may have also been used to help support the weight of the stones. If the stones do not come off the frame easily, then insert the pry bar between it and the stone. Add leverage to force the stone away. If you do not feel comfortable using a chisel, you may use a grout saw instead.

Step 2 – Dry Fit Stones

Choose a stone that fits in the area. You may use more than 1 stone to fill the area. Change the orientation of the stone as needed, in order for it to fir properly on the stone fireplace hearth.

Step 3 – Adhere the Stones

You can now place the new stones. Mix the thinset according to the directions, and then apply it to the wall using a trowel. Apply adhesive to the back of the stone and press it in place. Use materials rated for fireplaces and high-heat circumstances. Use an even amount of pressure and hold it in place for at least 2 minutes. This will help to press out any air bubbles between the stone and the frame of the stone fireplace hearth. Allowing the adhesive and the thinset time to interact for the 2 minutes, will create a strong bond. Do this for all of the stones that you plan to replace.

Step 4 – Finishing Up

Now that the stone is adhered to the frame of the stone fireplace hearth, you can finish it by grouting the gaps. You will use the same thinset you did to adhere the stones to fill in the gaps. Apply it directly over the stones using the trowel. Make sure that the gaps fill up as you even out the thinset.  As the thinset dries, a film will form over the stones. To remove this haze you need to use a clean rag. Wet it down with water and remove the excess, so that the rag is damp. Wipe it over the stones to remove the haze.