An undermount sink gives your kitchen a clean, modern style, but if it’s not secured properly, it can quickly turn into a plumbing headache. Over time, sinks can start to loosen, water can seep into gaps, and countertops may even get damaged. The key to avoiding these problems is using the right undermount sink adhesive along with reliable mounting hardware.
In this guide, we’ll explain the best adhesive for undermount sink installation, step-by-step instructions to secure it, and simple maintenance tips to keep your kitchen sink sturdy for years. You May Also Like: How to Connect Copper Pipe Without Soldering.
Looking for reliable help? Visit Garson Plumbing Today! to match with skilled pros and get your sink anchored right the first time.
Why Do Undermount Sinks Come Loose?
Undermount sinks are glued directly to the underside of a countertop, often granite, quartz, or solid surface. While this creates a seamless look, it also means the installation relies heavily on the strength of the kitchen sink adhesive and support clips. Over time, several issues can weaken the bond:
- Poor or rushed initial installation
- Low-quality adhesive not meant for kitchens
- Natural wear and tear of caulking
- Corroded or broken mounting clips
- Extra weight from pots, pans, or leaning on the sink
Signs that your sink may be coming loose include:
- Gaps forming between the sink and countertop
- Water dripping or staining around the edges
- Sink shifting or moving slightly when used
Tools and Materials You’ll Need
Before starting, gather these essentials:
Tools
- Screwdriver
- Adjustable wrench
- Putty knife
- Caulk gun
- Drill (if adding new support clips)
Materials
- High-quality undermount sink adhesive (preferably silicone-based)
- New undermount sink clips or brackets
- Wood braces or supports
- Rags and cleaning solution
💡 Pro Tip: Always choose the best adhesive for undermount sink — 100% waterproof silicone caulk rated for kitchen and bath use.
Step-by-Step: Securing an Undermount Kitchen Sink
1. Shut Off the Water
Turn off the water valves beneath the sink. If none are present, shut off the main water supply.
2. Disconnect Plumbing
Loosen and remove the drainpipe and faucet supply lines using a wrench. Set aside carefully.
3. Remove Old Clips and Adhesive
Unscrew any old clips under the sink. If the sink is still sticking, use a putty knife to gently pry it away. Scrape off the old adhesive from both the sink rim and countertop underside.
4. Install New Clips
Position new undermount sink clips or brackets. Drill pilot holes carefully if needed, making sure not to crack the countertop.
5. Apply Fresh Adhesive
Load your caulk gun with a kitchen sink adhesive and run a continuous bead around the sink’s top rim. This bead forms the waterproof bond between sink and countertop.
6. Position the Sink
Lift the sink back into place from below, aligning it carefully. Use wood braces to hold it snugly against the counter while you work.
7. Tighten the Mounting Clips
Slowly tighten screws on the clips to pull the sink flush with the countertop. Do not overtighten, as this may shift the adhesive.
8. Smooth and Clean
Wipe away any excess adhesive that squeezes out with a damp cloth. This ensures a clean seal.
9. Reconnect Plumbing
Reattach the drainpipe, faucet, and supply lines.
10. Let It Cure
Leave the braces in place and allow the adhesive to cure for at least 24 hours before using the sink.
DIY vs Professional Installation
You can absolutely tackle this project as a DIY if you’re confident with tools and plumbing basics. However, hiring a professional ensures:
- Stronger and longer-lasting installation
- Warranty protection on labor and materials
- Safe handling of delicate countertops like granite or quartz
If your sink is heavily damaged or your countertop is cracked, professional repair is highly recommended.
Maintaining Your Undermount Sink
To extend the life of your installation:
- Avoid putting extreme weight on the sink edges
- Don’t sit or stand inside the sink
- Wipe edges dry after washing to protect the adhesive for undermount sink
- Inspect clips and caulking once or twice a year
- Reapply caulk if small gaps appear
FAQs About Undermount Sink Adhesive
What is the best adhesive for undermount sink installation?
The best choice is a high-quality silicone caulk made for kitchens and bathrooms. It’s waterproof, flexible, and designed to bond sinks to stone or solid-surface countertops.
Can I use regular glue instead of kitchen sink adhesive?
No. Household glues and construction adhesives won’t last in wet conditions. Always use a specialized undermount sink adhesive.
How long does undermount sink adhesive last?
Typically 8–12 years, depending on moisture exposure and sink usage.
Why is my undermount sink falling down?
Most likely the original adhesive failed, or mounting clips corroded. Reinstallation with a stronger adhesive for undermount sink and new clips will fix the issue.
How much weight can a properly secured undermount sink hold?
With the correct adhesive and clips, it can easily hold normal kitchen use, including heavy pots. However, avoid extreme weight or standing inside the sink.
Final Thoughts
Securing an undermount sink isn’t difficult, but it requires the right approach. The combination of the best adhesive for undermount sink and strong clips ensures your sink stays watertight, sturdy, and stylish for years.
Whether you do it yourself or call in a pro, always choose a kitchen sink adhesive that’s designed for long-lasting performance in wet environments.
For fast, affordable service and quality installations, visit Garson Plumbing Today!—we’ll help keep everything securely anchored for years to come.
