A concrete fire table can be one of the most substantial pieces in an outdoor living space. But if you’re comparing fire tables online, it can be surprisingly difficult to tell how one was actually made.

Two tables may both be described as “concrete.” They may look similar in photographs. They may even have similar dimensions.

That doesn’t mean they’re built the same way.

Modern high-performance concrete and GFRC (glass fiber reinforced concrete) give manufacturers capabilities that are considerably different from conventional concrete construction. Mix design, water content, modern admixtures, fiber reinforcement, curing, structural design and sealing all influence how a finished fire table performs.

Most of those things are invisible once the table is finished.

So before buying a concrete fire table, here are the things worth understanding — and the questions worth asking.

Start With the Concrete Itself

One of the first questions shouldn’t be about color or even size. It should be: What is the fire table actually made from?

“Concrete” is an extremely broad description.

Traditional concrete relies on cement, aggregate and water to create a hardened matrix. Modern architectural concrete can be considerably more sophisticated.

At CastinCrete Designs, we use high-performance concrete and GFRC systems selected according to the particular application. That includes professional materials and admixture systems from manufacturers such as Kodiak Pro and Trinic.

Modern water reducers and plasticizers allow us to control workability without simply adding more water to the mix. That’s important because excess water can compromise concrete performance.

But the mix is only part of the equation.

Ask How the Fire Table Is Reinforced

Concrete is exceptionally strong in compression. Reinforcement helps it deal with tensile stresses and other forces the structure may experience.

For our fire tables, we primarily use alkali-resistant (AR) glass fiber reinforcement incorporated into the concrete.

Depending on the table’s size and design, we can also use fiberglass reinforcement and scrim. We generally avoid conventional steel reinforcement unless a particular application calls for it.

But simply asking whether a fire table contains fiber isn’t enough. Where and how a fire table is reinforced matters.

One of the most critical areas is the burner opening. The burner opening interrupts what would otherwise be a continuous concrete surface and creates an area that must contend with both structural and thermal stresses.

Through our own manufacturing experience here in Hartland, WI, we’ve developed additional reinforcement methods specifically for this area.

We don’t publish the details of that process because it’s part of how we build our tables. But if you’re comparing concrete fire tables, it’s worth asking a manufacturer: How is the concrete around your burner opening reinforced?

It’s a small construction detail that can have a large influence on long-term performance.

Should You Be Worried About Cracking?

Cracking is one of the first concerns many people have about buying anything made from concrete.

But there is an important distinction between conventional concrete construction and a purpose-built, high-performance GFRC fire table.

A modern GFRC fire table can combine a carefully controlled water-to-cement ratio, high-performance admixtures, AR glass fiber reinforcement, appropriate structural thickness and a controlled curing process.

At CastinCrete Designs, curing and hydration are treated as critical parts of manufacturing — not simply the period of time we wait before taking a table out of the shop.

Proper hydration allows the cementitious system to develop the properties the mix was designed to achieve. Controlling that process is every bit as important as choosing the ingredients that go into the mix.

That’s why we don’t tell customers that cracking is simply something they should expect from owning a concrete fire table.

Instead, the better question is: What has the manufacturer done — in its mix design, reinforcement, structure and curing process — to resist cracking?

That’s the question that gets underneath the word “concrete” and starts revealing how the product was actually made.

Thickness Matters, Too

Making GFRC doesn’t mean making the thinnest concrete structure possible. The geometry of the table still matters.

Our vertical walls are typically approximately 3/4 inch thick. The horizontal top surfaces are substantially heavier, generally ranging from approximately 1 1/4 to 1 1/2 inches, depending upon the size and structural requirements of the table.

We don’t use one construction specification for every design. A larger fire table, a different burner opening or a particular structural configuration can require a different approach.

That’s another worthwhile question for a manufacturer: How thick is the actual concrete — and does the construction change according to the size and design of the table?

Will Every Concrete Fire Table Look Exactly the Same?

No — and that’s one of the characteristics that makes handcrafted architectural concrete interesting.

Our batching process is carefully controlled, so we’re not looking for dramatic inconsistencies from one area of a table to another. But concrete isn’t a printed surface.

Subtle movement and tonal variation can develop through mixing, casting, curing and finishing. From one separately cast table to another, there can also be slight differences in color.

Within an individual CastinCrete Designs table, those variations tend to be subtle. Rather than making the table look inconsistent, they create depth and visual movement across the surface.

That’s an important expectation to establish when choosing a color from a sample: a sample represents the intended color and finish, but handcrafted concrete isn’t designed to reproduce the absolute uniformity of a factory-printed material.

Can a Concrete Fire Table Stay Outside All Year?

This is where theoretical durability becomes much less interesting than actual experience.

CastinCrete Designs is located in Hartland, Wisconsin. Our fire tables experience freezing temperatures, snow, rain, summer heat, direct sunlight, hail and repeated seasonal temperature changes.

And we have tables that have remained outdoors and uncovered for approximately five years through Wisconsin weather. With routine cleaning and occasional surface care, those tables continue to look remarkably close to when they were originally finished and sealed.

That’s important because we’re not basing our weather recommendations solely on what a material specification says should happen. We’re watching what actually happens to the products we manufacture.

Does a Concrete Fire Table Need to Be Covered?

We recommend covers, but perhaps not for the reason you might expect.

A properly made and sealed CastinCrete Designs fire table does not need a cover simply because it’s made from concrete. The primary benefit of a cover is convenience.

It keeps leaves, pollen, dirt, bird debris, snow and other material from accumulating on the table and in the burner area.

Our own experience with uncovered tables demonstrates that exposure to normal Wisconsin weather isn’t automatically a reason to hide a concrete fire table under a cover whenever it isn’t being used. The concrete, construction and sealer are supposed to do their jobs.

The Sealer Is Part of the System

A high-performance concrete fire table shouldn’t rely on bare concrete alone. The sealer protects the finished surface and influences stain resistance, weather performance and long-term appearance.

CastinCrete Designs uses a professional sealing system supplied by Kodiak Pro. We’ve continued using it for a simple reason: we’ve watched it perform outdoors year after year in Wisconsin.

For ongoing care, our tables don’t require an elaborate maintenance program. Cleaning as needed and occasionally applying the spray-on wax/polish we recommend can restore the surface appearance and keep the finish looking exceptionally good.

What Should You Really Compare Before Buying?

Price, dimensions and color are easy to compare. Construction is harder.

If you’re considering a concrete fire table, these are the questions worth asking any manufacturer:

• What type of concrete or GFRC system do you use?
• Do you use modern water-reducing admixtures rather than relying on additional water for workability?
• What type of fiber reinforcement is used?
• How is the burner opening reinforced?
• How thick are the top and walls?
• How is the concrete cured?
• What exterior sealer is used?
• Can the table remain outdoors year-round?
• What maintenance does it actually require?
• How long have your own fire tables been exposed to real outdoor conditions?

Those answers tell you considerably more than the word “concrete” ever will.

The Difference Is Usually Inside the Table

Some of the most important differences between concrete fire tables are things you’ll never see once the table arrives at your home.

You won’t see the water-to-cement ratio. You won’t see the admixtures. You won’t see most of the reinforcement. You won’t see what happened during curing. And you probably won’t know how much attention was given to the concrete surrounding the burner opening.

But years later, those decisions can matter considerably more than they did on delivery day.

At CastinCrete Designs, we build each fire table as a piece of architectural concrete — not simply as a container for a burner. The mix, reinforcement, structure, curing and finish are all part of the finished product.

Because when a fire table becomes the centerpiece of an outdoor space, how it’s built matters just as much as how it looks.

Want to see what a custom fire table looks like in a real setting? Read our Delafield custom fire table case study, or explore how we think about what separates a high-end fire table from everything else.