Mapei Mapesil Stone Matt Neutral Matte Silicone Sealant for Stone and Marble 300 ml

Mapesil Stone Matt by Mapei is the benchmark silicone sealant for those working with natural stone, marble, travertine, granite, slate, and porous materials in general. Unlike traditional neutral or acetoxy silicone sealants, it is formulated to never cause staining, halos, or colour changes in the substrate, even after years of exposure.

Its matte surface finish visually sets it apart from conventional silicones: instead of reflecting light like a standard glossy sealant, it blends in with the natural texture of the stone, enhancing the aesthetic of the surface rather than contrasting with it. For some colours, a speckled, textured version is also available, bringing the sealant even closer to the material effect of the substrate.

Formulated with neutral cure technology and solvent-free, Mapesil Stone Matt does not release acetic acid or plasticisers during or after curing. This makes it the correct product for all acid-sensitive surfaces — such as limestones, marbles, and alkaline materials — where traditional acetoxy silicones would inevitably cause staining issues.

Thanks to its low elastic modulus, it effectively absorbs high structural movement without cracking or detaching from the substrate. The seals remain unchanged over time even when exposed to weather, industrial atmospheres, thermal shock, and prolonged contact with water.

The product contains biocide, which inhibits mould growth in damp environments such as showers, bathrooms, and exposed outdoor areas. It is also MEKO-free and does not require safety labelling on the packaging.

Main areas of application:

• Floors and wall coverings in natural stone, marble, travertine, granite, slate
• Ventilated facades and prefabricated panels
• Perimeter sealing of windows and doors in settings with stone materials
• Connection and expansion joints subject to high movement, indoors and outdoors
• Cladding elements of the same or different nature
• Acid-sensitive surfaces on which acetoxy silicones cannot be used

Also suitable for application on low- or non-absorbent materials such as metals, painted surfaces, and glass, generally without the need for primer.

Available colours in 300 ml cartridge:

Smooth matte finish: White 100, Manhattan Grey 2000 110, Cement Grey 113, Black 120, Jasmine Beige 130, Beige 2000 132.

Speckled and textured finish: Manhattan Grey 2000 110 Speckled, Silver Grey 111 Speckled, Jasmine Beige 130 Speckled.

Main technical features:

• Movement capability: 25%
• Low elastic modulus
• Workability: about 15 minutes
• Coverage: about 3.1 linear metres per 300 ml cartridge (10x10 mm section)
• Finish: smooth matte or speckled and textured depending on the colour
• Contains biocide: delays mould growth
• MEKO-free: no safety labelling on the packaging
• Emission certification: EMICODE EC1 Plus
• Complies with EN 15651-1 (F-EXT-INT-CC), EN 15651-2 (G-CC), EN 15651-3 (XS1), EN 15651-4
• Stain-resistant certified according to ASTM C1248

The substrate must be sound, clean, dry, free of dust, friable parts, oils and release agents. For questionable or particularly sensitive surfaces, always carry out a preliminary test of adhesion and compatibility before application.
Cut off the threaded end of the cartridge, screw on the nozzle and cut it at 45° according to the desired joint width. Insert the cartridge into the gun and extrude the product continuously, completely filling the joint and avoiding the formation of air voids.
Smooth the surface with a suitable tool, such as Mapei Perfect Seal, moistened with UltraCare Smooth Silicone by Mapei, before a surface film forms. Remove the protective masking tape immediately after smoothing.
Do not apply on rubber surfaces or heavily plasticised plastic materials, or on bituminous surfaces, as the oils and plasticisers present in these materials may migrate to the surface, compromising the final result. If in doubt, consult Mapei Technical Service or carry out preliminary tests.
Do not apply at temperatures below +5°C or in conditions of relative humidity below 40%.

The 300 ml cartridge is made of plastic (polypropylene). Once empty and free of product residues, it should be disposed of in plastic recycling collection according to the procedures established by your municipality of residence. Do not release into the environment.

To safety data sheet