Countertops

How to Make a Concrete Fire Table

Feb 23, 2021 Justin Richardson

A fire table is a concrete countertop with a hole in it, and that is genuinely most of what you need to know. Concrete holds heat better than the alternatives, costs a fraction of a bought fire table, and takes acid stain — so the finish is yours to decide rather than the manufacturer’s. Mr. Ferrara of Dover Plains, New York designed, built and stained the one below himself, and his own account of how he did it is the useful part of this page.

A Desert Amber acid-stained fire table with a crushed glass trough.

Slab: 5000 psi concrete countertop mix, poured 1 1/2 in. thick around a metal grate
The trick: The bottom of the form is the top of the table — so the face comes out glass smooth
The trough: A 2 x 6 milled to 1/2 in. thick, screwed to the center of the form bottom
Reinforcement: Chopped fiberglass plus fiberglass net together — no steel needed
Edges: Caulk the form seams to get a rounded edge instead of a sharp one
Finish: Acid stain, water-based high gloss sealer, then ProWax Polish™

Shop EverStain™ Acid Stain →

Step 1: build the form

In his words: the form went together out of wood first, then a 2 x 6 was sanded and table-sawed down to half an inch thick and screwed to the center of the bottom of the form. That half-inch block is what creates the pocket in the finished top — the space you later fill with rocks, marbles, glass or fire.

“The bottom of the form is actually the top of the table. The seams of the form and the centerpiece of wood were then caulked to give a more rounded edge. The form was poured around a metal grate using 5000 psi concrete countertop mix for a strong slab at 1 1/2 in. thickness.”
— Mr. Ferrara, Dover Plains, NY

Two details there are worth repeating. Casting face-down against the smooth form is how you get a finished top without troweling one, and caulking the seams is a thirty-second job that decides whether the table has a sharp arris or a soft edge you can lean on.

Concrete Table Melamine Form Construction — The wooden frame.

Concrete Dining Table Form — The form ready to pour.

Reinforcement

High-zirconia alkali-resistant chopped fiberglass strengthens concrete and helps stop shrinkage cracking. When chopped fiberglass and fiberglass net are both used in a concrete countertop, steel reinforcement is not necessary. We do not sell either — a concrete countertop supplier will have both, and on a 1½ in. slab they are what keeps it in one piece.

chopped fiberglass reinforcement — Chopped fiberglass for the mix.

Concrete Table Fire Pit Form

The 2 x 6 block that forms the fire trough, screwed to the base of the form.

Step 2: demold and prepare the surface

After curing he sealed the underside first with high gloss water-based acrylic sealer, then flipped the slab and pulled the 2 x 6 out to reveal the pocket. A cement slurry went over the top to fill pinholes and leave a rough but flat surface imitating raw stone, then the top and edges were sanded and left to dry fully.

“I went over the table with a cement slurry to fill in the pinholes and create a rough but flat surface to imitate a raw stone finish. I finally sanded the top and edges and allowed to fully dry.”
— Mr. Ferrara

Slurry-and-sand is the standard countertop fix for pinholes, and it is worth doing even if you like the industrial look — open pinholes on a table hold crumbs and stain.

Unfinished Concrete Table

The cast slab, unpolished, with the trough revealed.

Step 3: acid stain and seal

Coffee Brown and Avocado EverStain™, sprayed in an oval pattern, allowed to dry somewhat, then repeated — that build-and-repeat is what gives the top its depth rather than a single flat pass. After the processing time he neutralized, cleaned with water, dried, and sealed with the high gloss water-based acrylic.

“Using the Coffee Brown and Avocado Acid Stains, I sprayed an oval pattern a few times, let dry somewhat and repeated. After the processing time was complete, I neutralized and cleaned with water, dried again, and applied the High Gloss Water-Based Acrylic Sealer. I then enlisted a strong friend who helped me finally place the table on its base in the dining room… After centering the table on its base and breathing two sighs of relief, I used the Countertop Wax to finish the concrete. I then filled the pocket with Crushed Glass Aggregate and added the fire.”
— Mr. Ferrara

Acid Staining Concrete Fire Table — Staining the cast top.

Acid Stained Concrete Fire Table — The finished acid-stained surface.

Base: Stained and lacquered pressure-treated 4 x 4s
Top coat: High gloss water-based acrylic sealer, then ProWax Polish™
Trough fill: Crushed glass aggregate, then the burner
Enlist help: A 1 1/2 in. concrete top is a two-person lift, at least

DIY Concrete Fire Table

The finished fire table on its 4 x 4 base.

Another one, in three colors

A second customer table, stained with Desert Amber, Malayan Buff and Shifting Sand EverStain™ and sealed to a high gloss. Three warm colors layered on one top is the approach that suits a fire table — you want the surface to look like it has heat in it. Layering technique is covered in how to layer two acid stain colors.