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Superior Stone and Tile Sealing with Capstone®

Chemours-square.jpg One of the best ways to maintain the value of residential and commercial real estate is by enhancing the appeal and longevity of the materials used to build these structures. Due to their beauty and durability, stone and tile are popular materials used to create walkways, walls, and surfaces.
Penetrating sealers are highly recommended treatments to adequately protect stone and tile from stains, corrosion, and mildew growth while preserving their natural look and beauty. To maximize the protection of stone and tile surfaces, Chemours has developed Capstone® repellents to offer market-leading penetrating sealer performance in water and oil repellency.

Capstone® Repellents for Penetrating Sealers

Capstone® repellents are fluoropolymers with linear fluorinated tail and polar head groups that are preferred active ingredients in penetrating stone and tile sealant formulations. Penetrating sealer formulations use carriers like water or solvents to penetrate and deliver the active ingredient in the upper layers of the surface. Capstone® repellents have extremely hydrophobic and oleophobic fluorinated tails that provide masonry superior repellence and resistance to staining from water and oil. The polar head groups on the polymer serve to anchor it to porous surfaces, orienting the polymer accordingly:

Capstone® polymers are based on short-chain C6 chemistry that meets the goals of the EPA 2010/15 PFOA Stewardship Program. Thus, Capstone® products are not made with PFOA and PFOS or used in manufacturing.

Penetrating sealers formulated with Capstone® have excellent performance when coating porous substrates. Thus, they are ideal for the following types of stone and tile:

  •   Granite
  •   Marble
  •   Terra-cotta
  •   Tile grouting
  •   Porous tiles
  •   Concrete
  •   Sandstone
  •   Saltillo

Capstone® Performance for Oil and Water Repellency

Capstone® provides better oil and water repellency and higher stain resistance than other repellants. As mentioned, it also does not alter the natural look of stone and tile and, since it is breathable and not film forming, allows moisture within stone and tile to escape. Thus, it is more effective at preventing staining from most household sources, accurately preserves the beauty of stone and tile, and helps prevent mold and mildew formation due to water that may enter the material from the sides.

The performance of penetrating sealers based on Capstone® versus competitive silicone was compared. In each test, the sealers were applied to limestone and Saltillo and allowed to dry for 3 days. Then, corn oil, Italian dressing, ketchup, mustard, grape juice, and coffee were placed on the sealed substrates. After 24 hours, the tiles were washed with detergent and scored from 0 to 4 based on the severity of stains remaining, where 0 corresponds with no stain, and 4 corresponds to a heavy stain. The results were then totaled for each tile and sample, and the classification of resistance was characterized.

Treatment Limestone
Oil Repellency Water Repellency Stain Resistance
Capstone® ST-100HS
(8 wt% in water)
6 6


Capstone® ST-110
(10 wt% in water)
3 4
Capstone® ST-200
(4 wt% in solvent)
2 2
Capstone® ST-300
(13 wt% in water)
1 7
Capstone® ST-500
(8 wt% in water)
2 3
Silicone Test #1 (water based) 19 17


Poor to Good
Silicone Test #2 (water based) 8 12
Silicone Test #3 (solvent based) 12 11
Silicone Test #4 (water based) 13 8
Silicone Test #5 (water based) 19 21
Untreated Test #1 16 14 None None Very Poor
Untreated Test #2 14 16
Untreated Test #3 13 14
Untreated Test #4 16 14
Untreated Test #5 19 21

From the above data, it’s clear that the penetrating sealers formulated with Capstone® vastly outperformed the silicone-based sealers, with Capstone® exhibiting significantly better repellency for oil-based products. Similar results have been observed using other types of stone, like granite and marble.

Below are two images and the staining pattern used in 24-hour stain tests conducted on Saltillo treated with a sealer using Capstone® ST-110 and untreated Saltillo. This test demonstrates the general stain resistance and excellent repellency Capstone® provides, especially to oil-based products, which show high penetration to untreated surfaces.

Staining Pattern

Vegetable oil

Lemon juice Bacon grease
Red wine Mustard Ketchup
Italian dressing Coffee (Blank)
Screenshot-2023-03-10-092536.jpg Screenshot-2023-03-10-092552.jpg

Grade Selection Guide for Capstone® Stone and Tile Sealer

There are several grades of Capstone® repellents available. Here are tables that provide recommendations for the best option depending on each stone and tile sealant formulation and the type of stone and tile it is applied to.


Penetrating Sealer Formulation Formulation pH Capstone® Grade Recommendation
Water based 4–6 ST-100HS or ST-110
Water based 7–8.5 ST-300
Water based 9–10 ST-500
Solvent based N/A ST-200
Capstone® Grade ST-100HS ST-110 ST-200 ST-300 ST-500
Solids (%) 25 25 35 14 25
pH 4–6 4–6 N/A 7–8.5 9–10
Medium Water Water Butyl acetate Water Water
VOC content (%) 1.1 1.3 65 <0.1 <0.1
Solubility Water Water Esters, ketones, mineral spirits Water Water
Typical dilution rate (%) 5–12 5–12 4–10 5–25 5–15
Granite surface performance Good Excellent Excellent Excellent Excellent
Limestone surface performance Good Good Excellent Excellent Excellent
Marble surface performance Fair Fair Excellent Excellent Excellent
Saltillo/Terra-cotta surface performance Excellent Fair Excellent Good Excellent
Sandstone surface performance Excellent Good Excellent Good Excellent
Slate surface performance Good Excellent Excellent Good Excellent
Concrete surface performance Excellent Good Excellent Excellent Excellent
Stone and tile sealers should first be formulated to discover the optimum concentration of Capstone® polymer to use based on each application and substrate it will be coating. Formulations may be applied using brushes, rollers, or mops. All water-based formulations should include biocides to prevent microbial growth, and formulations should be allowed to cure for at least 24 hours once applied.


Capstone® repellents provide market-leading performance in water and oil repellence for porous stone and tile surfaces. Therefore, penetrating sealers using Capstone® for stone and tile provide excellent stain resistance and no modification to natural stone’s look and beauty. They are also completely based on short-chain C6 chemistry that complies with the EPA 2010/2015 PFOA Stewardship Program, meaning they are not PFOA- or PFOS-based chemicals. Click below to speak to a specialist today to discuss a Capstone® repellent option for your penetrating sealer formulation.
Note: Capstone repellents are approved for penetrating sealers used only in indoor applications.


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