Concrete
Concrete brings architectural weight, raw texture, and a grounded presence into furniture design. SENTIENT works with cast and precast concrete for tabletops, bases, and accent elements, typically pairing it with solid wood or metal to balance the mass with warmth and detail. The material reads as honest and industrial, and it holds its own alongside the most refined hardwoods in our mixed-material compositions.
Types
Standard cast concrete is the traditional approach, poured into custom molds and cured to produce dense, heavy surfaces with the full tactile character of the material. GFRC (Glass Fiber Reinforced Concrete) replaces much of that mass with alkali-resistant glass fiber, which carries tensile and flexural load and lets a panel be cast thin. Compressive strength stays in the 8,000 to 10,000 PSI range, but compression was never the problem concrete needed help with. Polished concrete delivers a smooth, refined surface that reads more finished, while pigmented mixes allow custom colors matched to a specific project or palette. Each type can be cast in custom shapes and textures, giving concrete a versatility that the material’s raw reputation does not always suggest.
Characteristics
Concrete is heavy, fire-resistant, and almost impossible to dent. A traditional cast top at 1.5 to 2 inches thick runs roughly 19 to 25 pounds per square foot, which drives base engineering, floor loading, and how many people it takes to move the piece. GFRC brings that down to around 10 pounds per square foot, a saving of 50 to 60 percent, because the alkali-resistant glass fiber carries tension and lets the panel be cast thin. That is what the fiber is for. Concrete is already strong in compression and weak in tension and bending, and the fibers address the second half of that. The glass has to be alkali-resistant: standard E-glass is attacked by the alkalinity of the cement matrix and loses strength over time, so AR glass is a requirement rather than an upgrade. All concrete surfaces can be sealed to resist staining, though the material stays porous at a micro level and will absorb liquids wherever the sealer has worn thin or was never applied. Color varies naturally with mix design and curing conditions.
Common Uses
Concrete shows up in dining and coffee tabletops, furniture bases and pedestals, architectural accent panels, countertops, and outdoor furniture where its mass and weather resistance are advantages. It pairs well with live edge wood slabs, steel frames, and brass accents, creating mixed-material compositions that balance industrial weight with refined detail.
We integrate concrete into mixed-material compositions, pairing it with walnut, steel, or brass for a grounded, architectural feel. For lighter applications, GFRC gives us the concrete aesthetic without the extreme weight, opening up designs that would be impractical with standard poured concrete. We control the color, texture, and surface finish to match each project’s intent.
Care and Maintenance
For sealed concrete, wipe surfaces with a damp cloth and mild soap. Avoid acidic liquids like citrus juice or vinegar on unsealed surfaces, as they can etch and stain. Resealing depends on the sealer. Wax and penetrating sealers want renewal every six to 12 months on pieces in heavy use, applied to a clean, dry surface and given at least six hours to cure. Two-part urethane and epoxy sealers run for years before they need attention. Use coasters and trivets to protect against heat and moisture rings. Hairline cracks may develop over time. In a properly reinforced piece they are cosmetic and part of the material’s character, but a crack that keeps growing, offsets across its faces, or runs through a full section is a structural signal and should be looked at rather than sealed over.
Sources
- GFRCA Manual of Quality Standards (Glass Fiber Reinforced Concrete Association): Panel weights, AR glass fiber content, and flexural design
- PCI MNL-128, recommended practice for glass fiber reinforced concrete panels: Mix design, curing, and reinforcement requirements
- ACI 224R, control of cracking in concrete structures: When cracking is cosmetic and when it signals a structural problem
Related Materials
Glass
Tempered, laminated, and specialty glass for tabletops and accents.
Stone
Marble, quartzite, granite, and engineered stone for statement surfaces.
Custom Texture
Tactile, project-specific surface treatments across wood, metal, and composites.
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