Note: This DIY article is provided as a general guide only and is not intended to take the place of product-specific installation procedures; always follow applicable manufacturers’ instructions. Depending on your home’s age and condition, location within the home, and other potential factors, repairs and/or upgrades or other services may be necessary prior to the beginning and/or completion of your project that may involve the services of a home improvement professional. This article does not include advice pertaining to local building codes and/or any related inspections.

Kitchen counters contribute greatly to both the functionality and aesthetics of any modern kitchen. However, they are vulnerable to damage from water, crumbs, and other kitchen debris. Gaps exposed to moisture will attract mold and other health concerns. Knowing how to seal a kitchen countertop is necessary to prevent mold growth, water damage, and the premature aging of materials.

Silicone-based sealants excel in sealing kitchen counters, offering a durable barrier that naturally conforms to surfaces, expands to fill gaps, and resists heat and moisture. In this guide, we explore ten modern techniques for applying silicone sealant to kitchen counters to ensure they remain pristine and functional for years. Whether you’re installing a new kitchen or maintaining an existing one, understanding these sealing methods will help you provide lasting protection and enhanced durability to your counters.

What you need for sealing kitchen countertops

Before getting to work on your countertops, gather the right tools and supplies. Choose a high-quality silicone-based sealant designed for kitchens and baths, such as Supreme Silicone Kitchen & Bath Sealant, which offers waterproof protection and mold resistance. Silicone sealants remain flexible and maintain strong adhesion to surfaces, creating a lasting barrier against moisture and humidity. On average, you will need 4 grams of sealant per sealing task.

Supplies List

  • 100% Silicone Sealant: Ensure it’s a suitable color for your countertop material to avoid any staining
  • Caulk Gun: For precise application of your sealant
  • Painter’s Tape: To mask off areas around the sealant line for clean edges
  • Latex Gloves: To protect your hands during application
  • Soapy Water and Paper Towels: For cleaning the surface before application
  • Utility Blade and Caulk Tool: For opening the sealant tube and smoothing the applied sealant
  • Mineral Spirits or Isopropyl Alcohol: For cleaning and prepping the surface

Before starting, clean the countertop thoroughly with isopropyl alcohol and remove any old sealant so that the new application adheres well and performs effectively. Keep windows open when possible and be mindful of ventilation whenever you use cleaning solvents.

Before starting, clean the countertop thoroughly with isopropyl alcohol and remove any old sealant.

Kitchen counter sealing like a pro

With your supplies on hand, you’re ready to seal your countertops with a lasting protective barrier and a clean, professional aesthetic. Use these tips to get the most effective results.

  1. Seam Sealing

    To prevent debris, water, and humidity from accumulating in the seams where countertop sections join, apply a bead of silicone sealant. This method effectively seals the gaps and thwarts the growth of mold and mildew. Additionally, silicone sealants are not rigid when dry, leaving a flexible bond that will not crack. By creating a seamless barrier, seam sealing both protects against water damage and enhances the overall cleanliness and durability of your kitchen counters.

  2. Sink Edge Sealing

    Applying silicone sealant around the edges of the sink is crucial for creating a waterproof barrier. This barrier prevents excess moisture around the sink from seeping under the countertop and causing significant damage such as rot and mildew. Properly sealing the sink edge also helps maintain the structural integrity and appearance of the counter.

  3. Backsplash Sealing

    Apply silicone sealant along the joint where your countertop meets the backsplash to protect against water splashes and stains. Any glance at a bathroom mirror not recently cleaned will show you just how far water regularly splashes outside sinks. Applying sealant prevents moisture penetration from degrading wall materials over time and secures the backsplash, leaving a clean, hygienic surface for food preparation. This step is essential for maintaining the aesthetics and functionality of your kitchen.

  4. Edge Protection

    Seal your countertop’s front and side edges with silicone to safeguard against moisture and debris. Doing so will improve the countertop’s durability by resisting water ingress and preventing dirt and grime accumulation in most vulnerable areas. Taking the time to apply proper edge protection will add significant longevity and a pristine appearance to your counters.

  5. Fixture Sealing

    To secure fixtures like faucets and soap dispensers against water leaks, apply silicone sealant around their bases. Having sealed fixtures bases prevents moisture penetration into the cabinetry below, protecting against water damage and mold growth. Proper fixture sealing helps preserve kitchen installations and makes them cleaner overall.

  6. Joint Filling

    For countertops comprising multiple pieces or materials, use silicone sealant to fill the joints effectively. With sealed joints, you will create a smooth, uniform appearance while also preventing crumbs and liquids from getting trapped in between component sections. Time spent joint filling will pay off in the long run, leaving your counters easier to clean and maintain.

  7. Crack Repair

    Use silicone sealant to address existing cracks or chips in your countertop surfaces. Filling cracks mitigates further damage and deterioration. What appear to be minor, cosmetic imperfections today can quickly become larger, structural issues requiring replacement.

  8. Undermount Sink Installation

    Put a few beads of silicone around the rims of undermount sinks before setting them in place to leave a strong, waterproof bond. Sink installations are a common cause of mold ingress in kitchen counters.

  9. Temporary Seals

    Countertop materials are particularly vulnerable to damage during construction or renovation. Applying silicone to seal edges temporarily will protect exposed materials and surfaces from moisture, dust, and debris. Temporary seals are easy to apply and remove, offering a proactive solution for preserving the quality of your kitchen surfaces.

  10. Enhanced Aesthetics

    Silicone sealants do not take to paints. Pick colored silicone sealants to match or contrast with your countertop material. With the right color choice, homeowners can maintain any existing design themes or even add a unique accent detail.

Taking the DIY approach to home maintenance shouldn’t have to be a compromise of quality for thriftiness. With the right guidance — and the right materials — homeowners can maintain and enhance their kitchen countertops as effectively as the pros. If you’ve found this guide helpful, visit GE’s website or more end-to-end DIY guides for home improvement.