| Stone | How it behaves | Cleaning | Sealer |
|---|---|---|---|
| Flagstone | Irregular, porous, sand or mortar joints | Gentle soft-wash | Breathable penetrating |
| Bluestone | Weathers gray, fairly dense | Soft-wash | Enhancing (restore color) or natural |
| Travertine | Soft, pitted, acid-sensitive | pH-neutral only — never acidic | For calcium-based stone |
| Limestone | Soft, chalky, etches easily | pH-neutral only — never acidic | Breathable, non-clouding |
| Sandstone / slate | Layered, can flake under pressure | Low-pressure soft-wash | Penetrating, color-locking |
A natural-stone patio is one of the best-looking surfaces you can have in a Columbus backyard — and one of the easiest to damage by cleaning it the way you'd clean concrete. "Natural stone" covers several very different materials, and each has its own porosity, hardness, and chemistry. The cleaner and sealer that revive flagstone can dull travertine; the pressure that's fine on a concrete slab will pit sandstone. Here's how to tell what you have and treat it right.
First, figure out what stone you have
You don't need a geology degree — shape and color usually give it away:
- Flagstone — irregular, random-shaped slabs (often tan, gray, or rust), set with sand or mortar joints. The most common stone patio in central Ohio.
- Bluestone — rectangular, cut pieces in a blue-gray to gray tone; dense and smooth. Fades to a washed-out gray as the surface weathers.
- Travertine — cream, tan, or ivory with small natural pits and holes; soft and warm underfoot, which is why it's popular around pools.
- Limestone — smoother and chalkier than travertine, usually pale gray or buff; soft and quick to etch.
- Sandstone & slate — reddish, tan, or banded stone (sandstone) or dark layered stone (slate) that can flake in thin sheets if it's over-pressured.
The key split is calcium-based stone (travertine, limestone, and some flagstone), which is acid-sensitive, versus silica-based stone (most sandstone, slate, and much bluestone), which is tougher chemically but often more fragile physically. That one distinction drives everything below.
Cleaning: soft-wash beats power-wash on stone
The instinct to point a pressure washer at a dirty patio is exactly wrong for stone. High PSI blasts joint sand out of flagstone, pits soft travertine and limestone, and can peel layers off sandstone and slate. The professional approach is a soft wash — low pressure with a stone-safe cleaner doing the actual work — so the grime lifts without the stone taking a beating.
On cleaner choice, the rule is short: pH-neutral, never acidic. Vinegar, muriatic acid, and many general degreasers etch calcium-based stone into dull, cloudy patches that don't come back. For stubborn algae or black organic staining — common on the shaded, damp patios that stay green and slippery in Columbus — the fix is the right cleaner and dwell time, not more pressure.
Sealing: match the sealer to the stone
Nearly all stone wants a breathable, penetrating sealer rather than a glossy surface film. Stone holds moisture, and a film-forming topcoat can trap it, then cloud, blush, or peel — the difference is laid out in our guide to penetrating vs. film-forming sealers. Within the penetrating family you still get a look choice: a natural sealer keeps the current matte finish, while an enhancing sealer deepens the color — the move that brings weathered bluestone back to blue or warms up faded flagstone. Travertine and limestone specifically need a sealer formulated for calcium-based stone so it protects without clouding.
What Ohio's climate does to a stone patio
Central Ohio is a tough environment for porous stone. Water soaks into unsealed flagstone and travertine, freezes, expands, and works the surface apart over a few winters — the same freeze-thaw damage that cracks concrete, just showing up as flaking and spalling on stone instead. De-icing salt tracked over from walkways accelerates it, and shade plus our humidity keeps stone damp long enough to grow algae. Sealing is the single biggest thing that slows all of it, which is why stone in this climate wants resealing more often than the "every few years" you'll see quoted for milder regions — see how often to seal a patio in Ohio for the full schedule.
The one mistake that ruins stone patios
If you take away nothing else: don't clean stone with an acidic product or a full-power pressure washer. That single combination — the standard concrete-cleaning playbook — causes the etching, pitting, and delamination that most "my stone patio looks terrible now" problems trace back to, and it can't be undone with a sealer afterward. When in doubt on a stone you can't identify, or a patio you can't afford to get wrong, a pro will identify the stone and use a method matched to it. Our natural stone patio care service does exactly that, and the written estimate is always free.