Undermount sinks have become a popular choice for kitchen renovations in recent years due to their attractive appearance, ease of cleaning, and elegant overall design.
However, as usage time increases, countertops age, or the sink itself becomes damaged, many users face a practical question: should you remove the kitchen undermount kitchen sink from the bottom or the top when replacing it?
This article will provide a comprehensive analysis from the aspects of structural principles, fixing methods, disassembly steps, and precautions, allowing you to accurately understand the direction and method for replacing an undermount kitchen sink, avoiding detours and pitfalls. Whether you are a user preparing to do it yourself or a beginner wanting to understand the professional process, this article will help you understand it all at once.
Why can't an undermount sink be easily removed from the top like a countertop sink?
What is the core structure of a kitchen undermount sink? The installation method of an undermount sink determines that it generally cannot be pulled upwards from the countertop. The main fixing methods include:
1. Wrap-around metal bracket fixing (common in stone countertops)
Multiple metal brackets are attached to the bottom of the countertop, and screws are used to firmly tighten the edge of the sink, ensuring the sink is tightly attached to the countertop.
2. Structural adhesive bonding under the countertop (glass glue/marble glue/epoxy resin)
Undermount sinks use a large amount of sealant and structural adhesive for bonding, making the sink and countertop a unified whole.
3. Countertop weight compression structure (some sinks have pre-drilled edges that prevent upward passage)
The sink edge is wide, and the countertop opening is slightly smaller than the sink, making it impossible to detach the sink from above through the opening.
Based on the above reasons:
Undermount sinks almost never can be removed upwards; replacement must be done by disassembling from below and removing it downwards.
Next, we will explain the technical logic of "replacing downwards" in detail to help you fully understand the process.
Why must undermount sinks always be removed downwards when replacing them?
This is one of the most frequently asked questions by users: Why can't it be removed upwards?
The answer is clear: the installation method of an undermount kitchen sink dictates that it can only be removed from below.
1. The countertop opening is smaller than the sink's outer edge
The outer edge of a kitchen undermount sink "fits" against the bottom of the countertop and extends outwards by about 1-2 cm. This outer edge is larger than the countertop opening.
This means:
• When trying to move upwards, the sink's outer edge will be blocked by the countertop opening.
• There is simply no possibility of moving upwards.
2. Strong structural adhesive is applied from below
During installation, workers apply a large amount of structural adhesive to the bottom of the countertop. The adhesive forms a sealed, cured structure around the edge of the sink.
To break this adhesive, it must be cut and pried off from below.
3. Removing upwards means damaging the countertop
Even if forcibly removed upwards, it will cause:
• Countertop cracking
• Stone chipping
• Complete unusable countertop
Therefore, from both a safety and structural perspective, upward removal is not feasible.
Conclusion:
Replacing a kitchen undermount sink requires removing it from below, not from above.
Which parts need to be disconnected first when disassembling an undermount sink?
Many users mistakenly believe that simply loosening the screws is enough to remove the kitchen undermount kitchen sink, but the disassembly sequence is crucial. Incorrect steps can cause wall leaks, countertop damage, or even require redoing the entire kitchen.
The following are the preparatory steps before professional disassembly:
1. Turn off the water supply valves
Including:
• Cold water angle valve
• Hot water angle valve
To prevent accidental water spraying during disassembly.
2. Disassemble the drainage system
Including:
• S-bend
• Odor preventer
• Drain pipe
• Overflow pipe (if any)
Disassembly will relieve the weight of the sink, making subsequent operations easier.
3. Remove the faucet (depending on its location)
Most undermount sink faucets are fixed to the countertop, but the bottom nuts are often only accessible through the inside of the sink. Therefore, the sink must be removed before replacing the faucet. To safely replace a kitchen undermount sink, removing the faucet provides workers with more operating space.
4. Cutting the Structural Adhesive Around the Sink Edge
This is the most difficult part of the disassembly process, requiring the use of a specialized blade to cut from below.
How is the Disassembly Process for Replacing an Undermount Sink Performed?
Now for the practical steps. The entire disassembly process can be summarized as follows:
Step 1: Support the Bottom of the Sink
Because the sink will fall instantly if the supports or adhesive loosen, supports (wooden boards, jacks, etc.) must be used.
Step 2: Remove All Fixing Supports
Undermount kitchen sinks usually have multiple supports around them, which a professional will remove one by one.
Step 3: Cleanly Cut the Structural Adhesive
This is a crucial step:
• Use a blade saw
• Use a wire cutter
• Gently pry to avoid cracking the countertop
This requires patience and skill.
Step 4: Slowly Lower the Sink
Ideally, the sink will slowly fall with the supports and then be removed.
Undermount sinks are heavy and sometimes require two people to operate.
Can an ordinary user replace an undermount sink themselves?
Many users ask:
Can I remove an undermount sink myself?
Theoretically, it's possible with the right tools and patience, but practically speaking:
—It's not recommended for ordinary users to disassemble it themselves.
Reasons are as follows:
• Cutting the structural adhesive can easily damage the countertop.
• Removing the support bracket may cause the sink to suddenly fall.
• Repair costs for chipped countertop edges are extremely high.
• Reinstalling a kitchen undermount sink requires specialized adhesive and positioning clamps.
Therefore, replacing an undermount kitchen sink is a professional job and is best left to a professional plumber or cabinet maker.
What precautions should be taken when reinstalling an undermount sink after disassembly?
Removing the old sink is only the first step; the precautions for reinstallation are even more important.
The following points should be noted:
1. Countertop Edge Repair
Cutting the old adhesive can easily damage the inner edges of the countertop, requiring repair with stone adhesive.
2. Precisely Position the New Sink
Positioning clamps are required to ensure a tight fit between the sink and the countertop.
3. Use the Correct Structural Adhesive
Common adhesives include:
• Marble structural adhesive
• Industrial glass adhesive
• Epoxy resin adhesive
It is essential to use an adhesive suitable for the stone; otherwise, there is a risk of detachment.
4. Ensure a Seamless Fit Between the Sink and Countertop
Poor fit can lead to:
• Leaks
• Dirt buildup
• Mold growth and water seepage under the countertop
Will replacing an undermount sink damage the countertop?
This is one of the most pressing concerns for all users.
The answer is: Not necessarily, but there is a risk.
Factors affecting installation include:
• Whether the original installation adhesive is too hard
• Whether the countertop is made of a brittle material (such as natural marble)
• The experience of the professional handling the installation
• Whether the sink has been bonded to the countertop for many years
Generally, the risks are manageable as long as a professional disassembles it, but the following possibilities still exist:
• Small cracks in the countertop edge
• Limited space under the countertop making installation difficult
• Old adhesive making the sink very firmly bonded
• Extra caution is needed if the countertop material is brittle.
Does replacing an undermount sink require replacing the faucet?
Not necessarily.
However, it is recommended to replace the faucet at the same time in the following situations:
• The faucet has become loose after many years of use
• The faucet base has rust
• The old faucet nuts are difficult to remove
• The new sink and old faucet do not match
If space under the countertop is limited, disassembling the sink is the best time to replace the faucet.
Does replacing an undermount sink require removing the countertop?
In most cases, no.
Exceptions apply only to the following:
• The sink and countertop are completely integrated and cannot be cut.
• The countertop cutout size does not match the new sink.
• The countertop itself is cracked.
Normally, removing the old sink and installing the new one will not affect the countertop.
Replacing an Undermount Sink Always Requires Removing it Downwards
Undermount kitchen sinks must be removed downwards during replacement; they cannot be disassembled from above.
This is a technical fact determined by its installation structure and countertop cutout size; there are no exceptions.
If you are planning to replace your sink with a kitchen undermount sink, please be sure to understand the disassembly process, precautions, and necessary professional operations to ensure countertop safety, a secure sink installation, and long-term stable kitchen use.
What kind of buyers usually cooperate with Higold?
Higold works with global retailers, distributors, and brands who want high-quality kitchen sinks at factory-direct prices. Many of our partners purchase in bulk for wholesale supply, while others request ODM customization to match their brand identity. Our customers range from multinational chains to specialized distributors, all benefiting from competitive prices and certified high-quality products.
