Q. We have a home built in 1967 with black slate flooring on the interior and exterior porch and terrace. We have had some restoration done by a local stone mason but we are not happy with the finish. Even when last sealed it does not have the polished look or wet look that I would expect. What product or method to achieve this is suggested?
A.
Slate is a beautiful and durable natural stone, but achieving the right finish—especially a glossy or “wet look”—can be a bit tricky, and not all sealers or methods produce the same results.
From what you‘ve described, it sounds like the current restoration may not have included either the right type of finish or the correct surface preparation to achieve the look you’re after.
Here’s what you need to know:
Most slate has a naturally textured, matte surface (cleft finish), and it typically doesn‘t polish to a high gloss like marble or granite. However, there are ways to enhance the color and give it that richer, "wet" look you’re envisioning.
To achieve a wet-look finish on slate, there are two primary options:
Color-Enhancing Penetrating Sealers
These bring out the deeper tones of the slate, enriching the color and giving a low-sheen, natural "wet stone" look—without creating a surface film. These are great for interior and exterior use, and they don’t peel or flake over time. However, they do not produce a true gloss.
Topical Gloss Sealers (Film-Forming Coatings)
If you‘re looking for a polished or high-gloss finish, a topical acrylic or polyurethane sealer may be required. These sit on top of the stone and create a shiny surface. While they do offer the "wet look," they are best used indoors only, as UV exposure and moisture outdoors can cause peeling or yellowing over time unless a high-performance, exterior-rated product is used.
Before applying any sealer—especially a topical one—the slate must be thoroughly cleaned and any previous coatings or sealers should be stripped off. Inadequate prep is a common reason sealers don’t perform or appear as expected.
For best results—especially if you‘re after a uniform, durable, glossy finish—we recommend having a professional stone restoration company evaluate the slate, test a few products in a small area, and apply the finish correctly. It may require honing (light mechanical smoothing) before sealing to improve the final appearance.
Use the Find a PRO (www.surfacecarepros.com) feature to find a qualified stone restoration contractor that services your area to inspect your slate and recommend the best method and product based on your goals, whether you’re looking for a subtle enhancement or a high-gloss finish. In many cases, a deep cleaning, followed by the application of a premium enhancer or sealer, makes a dramatic difference.
Article ID: 750
Created: May 8, 2025
Last Updated: May 8, 2025
Author: Deborah Nelson
Online URL: https://kb.surfacecarepros.com/article/slate-repair-sealing-750.html