Main Types of Concrete Finishes
Concrete is a fundamental building material used in countless construction projects. Its versatility allows it to be molded into any shape while wet, creating limitless design possibilities. Once hardened, the final appearance and texture of the concrete surface is determined by the finishing techniques utilized.
Concrete finishes refer to various methods that alter the final aesthetic, durability, and functionality of concrete surfaces. Finishing processes are typically performed while concrete is still wet or plastic to permanently shape its final form. There are several major types of concrete finishes, each creating distinct textures with their own visual appeal, slip-resistance, and maintenance requirements.
Exposed Aggregate Finishes
Exposed aggregate is a popular decorative concrete finish that reveals the coarse aggregate in the concrete mix, such as pebbles, gravel, or crushed stone. It is achieved by removing the top layer of cement paste, chemically or mechanically, to uncover the aggregate underneath.
The exposed stones create an organic, rugged texture with natural appeal. Aggregate concrete finishes are often used for driveways, walkways, patios, pool decks, and commercial spaces. Benefits include:
- Visually interesting - multi-colored stones create a unique mottle
- Durable and slip resistant
- Low maintenance compared to other finishes
The size of aggregate and depth of exposure can be customized, from lightly exposed to heavily exposed, depending on the desired appearance. Protective sealants help retain the texture and prevent erosion of aggregates over time.
Achieving Exposed Aggregate Finishes
Common methods of exposing aggregate include:
- Surface Retarders - Chemicals delay hardening of the top layer of concrete to facilitate removal
- Water Washing - Top concrete washed off with water jets at the appropriate timing
- Abrasion - Surface scraped or sandblasted to expose aggregate
Proper concrete mix design, pouring techniques, and precise timing during the exposure process are imperative to create an even, attractive finish.
Broom Finished Concrete
Broom finishing involves texturing freshly placed concrete with a stiff bristled broom. The broom strokes create shallow grooves across the surface that resemble faint corduroy lines. Broom finished concrete is identifiable by its low slip resistance and sandy appearance.
Broom finishes are extensively used for driveways, sidewalks, patios, pool surrounds, and commercial spaces like warehouses. Benefits include:
- Enhances traction and safety
- Sweeps away excess water and debris
- Economical and easy technique
Broom finished concrete offers slightly increased traction but still requires caution when wet. The width of broom, pressure applied, and timing of brooming determines the depth and profile of the ridges.
Broom Finish Techniques
There are several approaches to broom finishing:
- Standing - Static brooming in perpendicular passes
- Drawing - Pulling broom by hand across concrete
- Circular - Sweeping broom in circles evenly across surface
Maintaining consistent overlapping strokes and adequate pressure produces an even finish. Brooming concrete too early or late can cause an irregular, unfinished appearance.
Trowel Finished Concrete
Troweling uses a flat, smooth steel blade to create an ultra-smooth concrete finish. Power trowels, floor polishers, and hand troweling produce glossy surfaces essentially free of flaws and blemishes.
Trowel finishes are popular for decorative horizontal surfaces like countertops, floors, table tops. Benefits include:
- Seamless and blemish-free appearance
- Improved durability and abrasion-resistance
- Easily cleaned and maintained
The smoothness achieved depends on the number trowel passes, pressure applied, and timing. While attractive, troweled concrete can become dangerously slick when wet if left untreated.
Troweling Techniques
There are two troweling methods:
- Hand Troweling - Using a hand trowel in successive passes
- Power Troweling - Riding or walking behind motorized rotary trowels
Multiple passes are needed to achieve a smooth, dense finish. Troweling too early causes blisters while late troweling causes variances. Timely finishing ensures concrete consolidation before hardening starts.
Stamped Concrete
Stamped concrete imprints realistic patterns into concrete to mimic brick, stone, wood, tile, or custom textures. Mats or textured rollers are pressed into concrete, leaving a permanent 3D design when lifted.
Stamped concrete is extremely versatile and commonly used for pool decks, patios, driveways, sidewalks, commercial building entryways. Benefits include:
- Wide range of possible looks and textures
- More cost-effective than real stone or brick
- Stain-resistant and easy to clean
Hundreds of stamp patterns and designs can recreate natural stones, geometric shapes, logos, and more in concrete. Stamped coloring techniques like integral coloring, antiquing release powder, and staining enhance realism.
Stamped Concrete Process
The basic stamping process involves:
- Pouring and smoothing concrete
- Applying release agent so stamps don't stick
- Pressing mats/stamps into concrete
- Lifting stamps to reveal impression
- Curing and sealing concrete
Proper mix design, moisture control, release agent usage, and stamp pressure prevent defects in the stamped finish.
Float Finished Concrete
Floating uses flat blades to impart a lightly textured, consistent surface to freshly placed concrete. Float finishing removes minor imperfections and levels the surface before final finishing.
Floating prepares concrete for techniques like brooming, troweling, and stamping. It consolidates the concrete surface after screeding. Benefits include:
- Smoothes and shapes plastic concrete
- Compacts aggregate and fills voids
- Levels surface for subsequent finishing
Power floats on poles are commonly used but hand-held floats can also finish small projects. The texture achieved depends on the float's size and number of passes.
Floating Techniques
There are two primary float finishing methods:
- Hand Floating - Using magnesium or wood hand floats
- Machine Floating - Riding power floats on circular blades
Precise float handling prevents uneven spots or swirl marks. Float finishing at the optimal time smooths concrete without drawing excess moisture to the surface before additional finishing.
Concrete finishes encompass various techniques that alter the final appearance and texture of concrete to meet aesthetic and functional requirements. Major types ranging from exposed aggregate to stamped concrete each impart unique visual styles and properties.
Choosing the appropriate concrete finish starts with assessing needs, cost considerations, performance, maintenance and overall goals early when planning a project. Consulting concrete specialists helps identify the optimal solutions for achieving the perfect concrete finish.