How to Build a Stone Fire Pit on a Wooden Deck

Drill a hole in a ½-inch thick 4-by-4 foot cement board that is large enough to fit the gas and power lines coming up through the deck.

Seal both sides of the cement board with a mastic sealant. Allow the sealant to dry and set it in place so the gas and power lines come through the hole.

Place a 6-inch-tall manhole extension over the cement board in the location you want to build the fire pit. Use chalk to outline the inside and outside rings of the manhole extension. Remove the extension.

Use a trowel to spread mortar in the ring you outlined with chalk.

Place a manhole extension over the mortar and spread mortar on the top edge of the extension. Place a second manhole extension over the first and repeat this process for the third extension.

Spread mortar along the outside of the manhole extensions to seal the gaps.

Working in small sections, spread mortar on the cement board that equals the length of the face stones you want to use, plus 2 inches. You may end up placing mortar on your deck if the face stones are long.

Place face stones 2 inches away from the fire pit, following its curve. Fill the gaps between the stones and the manhole extensions with mortar, as well as the spaces between each face stone.

Press small pieces of face stone in the 2-inch area between the manhole extensions and the larger stones, which will add support to the finished product.

Spread a layer of mortar over the face stones and stack a new layer of stone on top. Fill in all the gaps with additional mortar and press more small pieces of stone into the area between the manhole extensions and the larger stones. Continue this process until the flagstones are at the same height as the top of the stacked manhole extensions.

Lay the capstones. Spread mortar over the top layer of face stones, the top manhole extension and the gap between the two. Place capstones over the mortar that are long enough to cover the inside of the manhole extension to the outside edge of the face stones. Fill the gaps between the capstones with mortar and allow the mortar to cure.

Attach the outlet plug that comes with the fire pit kit to the power line inside the pit you built.

Attach a 4-foot flex hose to the end the gas line. Attach the opposite end of the hose to the gas valve on the fire pit kit.

Line the bottom of the pit with enough cinderblocks so the top of the pan in the kit is at the same height as the pit.

Place the kit inside the fire pit and spread lava rocks over the bottom of the pan. Avoid covering the gas jets with the rocks.

Carefully place ceramic logs over the gas jets so the jets are not visible.