Exposed Aggregate Concrete: How It's Done and When It Fits

Summary:

Cesar explains that exposed aggregate reveals the stone already present in the concrete by removing the thin layer of paste covering it after the pour. The size and color of the aggregate chosen determines how the finished surface looks, which makes stone selection part of the homeowner's decision. He acknowledges its appeal — natural texture and a look that hides wear better than a plain surface — but he is candid about its drawback in this region. Exposed aggregate becomes slippery over time in Washington's persistently wet conditions, so when homeowners ask about it for a driveway or a primary walkway, he typically steers them toward broom finish and explains the safety reasoning behind that recommendation.

Answer:

Exposed aggregate is where you see the stone in the concrete instead of a smooth or brushed surface. The stone is already in the mix, and after the pour we take off that thin layer of paste on top so the rock underneath comes through. What it ends up looking like depends a lot on the aggregate that's in it, the size and the color of the stone, so that's a choice the homeowner makes together with us. People like it because it has real texture and a natural look, and it doesn't show wear the same way a plain gray surface does. I'll be honest with people about it though. Over here in Washington, exposed aggregate gets slippery with the time. It's wet most of the year and that surface will get slick on you. So when somebody asks me about it for a driveway or a main walkway, I usually tell them broom finish is the safer choice and I explain why. If they want it somewhere that makes sense, we do it.