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Ghostshield Siloxa-Tek 8500 is a clear, water-based penetrating water and salt repellent for concrete, brick, pavers, stucco and other masonry. It’s aimed at homeowners and contractors who want to protect driveways, patios, garage slabs and walls from water, de-icing salts and freeze-thaw damage without changing the look of the surface. The bottom line: it’s a well-reviewed, easy-to-apply invisible sealer, but it costs more than many alternatives, it doesn’t block oil stains, and it can’t fix cracked or unsound concrete.
| Home Depot rating | ★ 4.8/5 (1,332 Home Depot reviews) |
| Type | Penetrating, non-film-forming water and chloride repellent |
| Chemistry | Water-based silane (isooctyltriethoxysilane) |
| VOC | 90 g/L maximum |
| Finish | Natural flat; milky in the jug, dries clear |
| Coverage | 150–400 sq ft/gal for one coat; 75–200 sq ft/gal for two coats |
| Coats | Two, wet-on-wet |
| Dry/traffic | Dries in about 4–6 hours at 70°F and 50% RH; traffic in 24 hours |
| Cure | Water repellency keeps developing for up to 7 days |
| Best for | Driveways, patios, pool decks, pavers, garage slabs, brick, stucco, block walls |
| Not for | Oil-stain protection, cracked or unsound surfaces, damp slabs over 4% moisture |
| New concrete | After proper cure, typically 14–28 days |
Watch: Siloxa-Tek 8500 in 60 seconds
What It Is / How It Works
Siloxa-Tek 8500 is a silane-based penetrating sealer. Ghostshield's technical data sheet lists the active as isooctyltriethoxysilane, a small silane molecule that soaks into the pores and capillaries of concrete and masonry and reacts there to form a water-repellent lining. It doesn't leave a coating on top, so there's nothing to peel, scuff or yellow, and the surface stays breathable: water vapor can still escape while liquid water and dissolved salts bead up and stay out.
It's still sold at Lowe's, Home Depot and online as a ready-to-use gallon, an "ultra concentrate" gallon that you mix with 4 parts water (distilled is recommended) to make 5 gallons, and in drums. Lowe's lists the ready-to-use version as Model 8500 and notes that it meets DOT minimum active-ingredient levels. Ghostshield markets it with a "100 year warranty." The formal warranty terms are much narrower and limit liability, so read them before you count on that number.
Where It Works Best (and where it doesn't)
It's a good fit for exterior flatwork in climates with freeze-thaw cycles and road salt: driveways, sidewalks, patios and pool decks. It also works on pavers, exposed aggregate, brick, stucco and concrete block. Because it doesn't change the surface appearance or add slip risk, it suits places where a glossy acrylic would be a problem. Owners on Lowe's commonly report easy pump-sprayer or roller application, a clear finish and strong water beading after rain and snow.
It's not the right product if your main goal is keeping oil, grease or car fluids from staining a garage floor or driveway; Ghostshield sells a separate fluorocarbon-boosted version (Siloxa-Tek 8505) for that. Like every penetrating sealer, it won't stop water entering through cracks, failed joints, bad flashing or defective structural waterproofing. The data sheet also requires surface moisture under 4% by weight, so it isn't a fix for a wet slab. For more invisible options, see our best silane-siloxane concrete sealers guide.
Pros
- Invisible, natural flat finish that doesn't change the look or traction
- Breathable and non-film-forming, so it can't peel or delaminate
- Repels water and de-icing salts on a wide range of concrete and masonry
- Water-based and easy to spray or roll
- Concentrate option cuts shipping weight
- Very high owner ratings at Lowe's (4.9/5 across 1,200+ reviews when checked)
Cons
- Price is the most common owner complaint
- No oil or grease repellency (that's the 8505's job)
- Higher VOC (90 g/L max) than some water-based competitors
- Data sheet doesn't publish an actives percentage or a measured penetration depth
- Second coats can puddle if over-applied and need to be brushed out
- Strict conditions: 40–95°F, no rain for 12 hours, dry substrate
How to Apply It
- Prep the surface. Remove oil, grease, curing compounds, efflorescence, paint and old sealers by power washing, acid etching or mechanical scarifying. Neutralize and rinse after any acid, then let it dry.
- Check moisture and weather. Surface moisture should be under 4% with no standing water. Air and surface should be 40–95°F, with no freeze expected within 8 hours and no rain within 12.
- Test a small area. Let it dry 5–7 days before judging the result.
- Mix if needed. Stir well. For the ultra concentrate, mix 1 part concentrate with 4 parts water. Don't dilute the ready-to-use version.
- First coat. Apply to saturation with a roller, brush or low-pressure, non-atomizing sprayer. Let it penetrate 5–10 minutes.
- Second coat. Apply wet-on-wet, using less material. Roll or broom out any puddles.
- Protect and cure. Cover overspray targets (glass, plants, cars). Allow 24 hours before traffic; repellency keeps building for up to 7 days. Clean tools with hot, soapy water.
How It Compares
Versus PROSOCO Saltguard WB: both are water-based penetrating repellents aimed at salt exposure. Saltguard WB lists very low VOC (under 25 g/L) and 5% actives, and is sold mostly through distributors. Siloxa-Tek 8500 is easier to buy at big-box stores and online and uses a two-coat wet-on-wet process.
Versus Ghostshield Siloxa-Tek 8505: the 8505 adds a fluorocarbon for oil and grease repellency. If you're sealing a garage or a driveway where cars drip, it's worth the extra cost. For water and salt alone, the 8500 covers the need.
Versus acrylic sealers: acrylics add gloss and color and resist stains, but they form a film that wears and can get slick. Siloxa-Tek 8500 is the choice when you want protection you can't see. Our best driveway sealer guide compares both types.
FAQ
Is Siloxa-Tek 8500 waterproof?
It's a water repellent: it makes concrete and masonry shed water and resist salt, but it doesn't seal cracks or stop water coming through defects or failed joints.
Will it change the look of my driveway or pavers?
Ghostshield says it dries clear with a natural flat finish that doesn't alter appearance. Most owners report no visible change, though one Lowe's reviewer noted colors "popped" slightly on pavers. Test first.
Can I use it on new concrete?
Yes, once the concrete is properly cured, which Ghostshield puts at typically 14–28 days. Remove any curing compound first so it can penetrate.
Does it stop oil stains?
It's marketed as a water and salt repellent, not an oil repellent. For oil and grease resistance, look at Siloxa-Tek 8505 or a coating.
Verdict
Siloxa-Tek 8500 is a strong option for invisible, breathable water and salt protection on driveways, patios, pavers and masonry. It's easy to apply, widely available and very well rated by owners. The trade-offs are price, a higher VOC ceiling than some water-based rivals, no oil repellency, and a data sheet that leaves out actives and penetration figures. Pick the 8505 if oil stains are a concern.
How we reviewed this product: this is a research-based review built from the manufacturer's technical data sheet and current retail listings. We have not run our own hands-on tests of this product. Details were checked in October 2026; always follow the current label.
