Slate Stone Fireplace: Hearth Construction

Slate is a natural choice for a stone fireplace hearth, as it is durable, holds fire, and is long lasting.

Slate is also attractive, and now comes in a variety of finishes. Installing your own stone fireplace hearth is straightforward. Follow these steps to ensure a professional looking finish. You will need these tools and materials.

  • Measuring tape
  • Diamond bladed saw (available to hire)
  • Fireproof thincut adhesive
  • Grout

Step 1 – Measure the Hearth Space

Measure the hearth space and decide whether you want a slate hearth surface that is flush with the flooring or slightly raised. Make a note of the intended hearth slate “depth” accordingly.

Step 2 – Prepare the Groundwork

Make sure that the hearth bed is structurally sound, clean and dry. Brush the hearth bed to make sure that there is no loose debris. The hearth bed will probably be made from concrete. If you discover any cracks, they must be repaired at this stage to ensure the structural integrity of the hearth.

Step 3 – Cut the Stone to Fit Your Stone Fireplace Hearth

If possible, ask the stone merchant to cut the slate to fit the space. The stone merchant will have a diamond edged blade on his saw, and will be well practised in this skill. Diamond edged bladed saws are worth hiring for this task, to ensure a clean cut. Alternatively use a carbide rod saw, but be careful. You must not use a regular tile cutter to cut your slate, as it will not provide a clean edge, instead creating a jagged line which will render the slate useless.

Step 4 – Stick Down the Slate

Make sure that the adhesive you use is specifically suitable for slate, and apply it in accordance with the manufacturer’s instructions. A fireproof thincut adhesive is the best choice, made from silica sand, Portland cement and a bonding agent. Crucially, the adhesive needs to be fireproof. If you do find that you have made a mistake with your measurements and cut the hearth slate too small, you can fill a thin gap with gray grout, to join the flooring to the stone fireplace hearth. This will prevent unsightly gaps and cracks. Any stray must be wiped off immediately to prevent stains.

Step 5 – Wait for Adhesive to Set

Wait at least 48 hours before the adhesive has set before using the fireplace.