In Plain English
Quick Answer
A decorative concrete finish where the top layer is washed away to reveal the colorful stones inside the mix.
Definition
Definition
A decorative concrete finish achieved by removing the surface mortar to reveal the aggregate (stones, pebbles, or other materials) embedded in the concrete. The process involves applying a surface retarder, then pressure-washing the surface after the concrete has begun to set. Exposed aggregate provides a textured, slip-resistant surface with visual appeal.
Context
Why It Matters in Bidding
Exposed aggregate is a finish upgrade that materially raises concrete bid prices through specialty aggregate, surface retarder, extra wash-down labor, and the schedule sensitivity of timing the wash to the set. Estimators must price it as a distinct finish rather than rolling it into standard flatwork, and should flag mockup requirements that add cost and add float risk to the pour sequence.
Example
Example
Pricing a hotel entry plaza, the estimator carries exposed aggregate as a premium finish, adding select decorative stone, retarder, sealer, and an owner-approved mockup panel to the unit price instead of using the standard broom-finish rate.
See Also
Related Terms
FAQ
Questions Contractors Ask
How much more does exposed aggregate cost than a broom finish?
It is consistently a premium finish, driven by decorative aggregate selection, surface retarder, additional skilled wash-and-expose labor, and a protective sealer. Many specs also require an approved mockup. Estimators should price it per square foot above standard flatwork and confirm the aggregate type and seeding method, since broadcast-seeded finishes cost more than integral mixes.
What scheduling risk does exposed aggregate add to a bid?
The wash-off window is set-time sensitive: too early washes out paste, too late leaves aggregate buried. This narrow window means crews may work off-hours or stage labor on standby, and weather delays compound the risk. Carry contingency labor and note the timing constraint so the schedule and bid reflect the finishing crew commitment.
Should a mockup be included in the exposed aggregate price?
If the specifications call for an approved sample panel, yes. The mockup establishes color, aggregate density, and texture for owner sign-off and becomes the acceptance standard. Pricing the panel, its placement, and possible rework into the bid prevents a change order later and protects the estimator if the final finish is challenged.
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