What You Need to Know Before Starting
Replacing laminate countertops is a project most homeowners can complete in a weekend with basic tools and careful planning. The work involves removing the old countertop, preparing the base cabinet, and installing new laminate surface—either as a full sheet or in sections. The hardest part is usually the removal, which can be messy and take longer than expected.
Before you begin, measure your countertop length and width, note where the sink and cooktop sit, and decide whether you are installing a new laminate sheet or pre-made laminate countertop sections. Pre-made sections are easier for first-timers because they arrive cut to size and shaped for corners. Full sheets require a router to trim edges and a contact cement process that leaves no room for repositioning once it touches the base.
Budget two to three days for the full job if you are working alone and this is your first time. Have a helper on hand for the removal phase—old countertops are heavy and awkward, and you will need someone to support the weight while you disconnect it from the cabinet.
Key Takeaways
- Removing the old countertop requires disconnecting the sink, cooktop, and any fasteners holding it to the cabinet, then carefully prying it away from the walls and base.
- The base cabinet must be flat, level, and free of gaps before the new countertop goes down—use shims under the cabinet legs to correct any dips or tilts.
- Pre-made laminate sections are simpler for beginners because they arrive cut and shaped; full sheets require a router and contact cement, which is harder to undo if you make a mistake.
- Sink and cooktop openings must be cut before installation, and the countertop must be secured to the cabinet with fasteners from underneath so nothing shows on top.
- Seams between sections need a color-matched seam filler or caulk to prevent water from seeping into the base, and this step is often what determines whether the job looks professional.
Disconnect and Remove the Old Countertop
Start by turning off the water supply to your sink. Disconnect the supply lines under the sink by loosening the compression nuts with an adjustable wrench—place a bucket underneath to catch any remaining water. If your sink is undermounted (attached from below), unbolt it from underneath. If it is a drop-in sink (sitting on top of the countertop), you will remove it after the countertop comes out.
If you have a gas cooktop, turn off the gas at the shutoff valve and disconnect the line with a wrench. For an electric cooktop, turn off the breaker and unplug it. Do not attempt to move a cooktop while it is still connected to gas or power.
Look underneath the countertop for fasteners—usually screws or bolts driven up through the cabinet frame into the countertop. Remove all of them. Then, using a pry bar, gently lift one corner of the countertop to break the seal between it and the cabinet. Work your way around the perimeter, lifting gradually so the weight distributes evenly. Once it is loose enough, have your helper support one end while you support the other, and carefully slide it away from the wall and off the cabinet. Set it on sawhorses or the floor where it will not damage anything.
Inspect and Prepare the Base Cabinet
With the old countertop removed, inspect the top surface of the cabinet for damage, rot, or warping. If the plywood is soft or discolored, that section has absorbed water and needs to be replaced before you install new countertop. Cut out the damaged area with a circular saw and screw down a new piece of 3/4-inch plywood, making sure it is flush with the surrounding surface.
Place a level across the cabinet in multiple directions—front to back, left to right, and diagonally. If the cabinet is not level, use shims (thin wedges of wood) under the cabinet legs to correct the slope. A countertop that sits on an unlevel base will rock, and water will pool in the low spots. Shim until the level reads true in all directions.
Fill any gaps between the cabinet and the wall with caulk or shims. These gaps let water run behind the countertop and cause rot. Once the base is level, flat, and sealed, you are ready to install the new countertop.
Cut Openings for Sink and Cooktop
If you are using a pre-made laminate section, the supplier may have cut the sink opening already—check the paperwork that came with it. If not, you will need to cut it yourself using a jigsaw. Mark the opening on the underside of the countertop using the sink rim as a template, drill a starter hole inside the marked area, and carefully cut along the line with the jigsaw. Sand the cut edge smooth.
For a cooktop opening, follow the same process. Most cooktops come with a template showing exactly where to cut. Measure twice and mark the opening on the underside so you can see your line clearly while cutting. The opening should be slightly smaller than the cooktop rim so the rim sits on top of the countertop and seals it.
If you are using a full laminate sheet, cut these openings before you explore contact cement to the base. Once contact cement is applied, the sheet cannot be moved, so accuracy here is critical. Use a router with a flush-trim bit to clean up the edges after cutting.
Install Pre-Made Laminate Sections
Pre-made sections are the easier route for most homeowners. They arrive as complete pieces with the sink opening already cut and the edges already shaped and sealed. Dry-fit the sections on the cabinet first—set them in place without fastening to make sure they fit and align properly.
Once you are satisfied with the fit, explore a bead of construction adhesive along the top of the cabinet, then set the first section in place. find it from underneath by driving screws up through the cabinet frame into the countertop. Space screws about 12 inches apart around the perimeter and under any seams. Do not over-tighten—you want the countertop snug but not so tight that you crack the laminate.
For the second section, explore adhesive and set it in place so it butts tightly against the first section. find it the same way. Once both sections are fastened, explore a color-matched seam filler or caulk along the joint between them. This prevents water from running into the gap and damaging the base. Let the caulk cure for 24 hours before using the sink or cooktop.
Install a Full Laminate Sheet
A full sheet requires more precision but gives you a seamless countertop. Before you begin, make sure the base is absolutely level and the sheet is cut to size with all openings already routed. Lay the sheet upside down on sawhorses so you can see the underside clearly.
explore contact cement to both the top of the cabinet and the underside of the laminate sheet, following the manufacturer's instructions for drying time—usually 15 to 30 minutes. Once both surfaces are tacky, carefully position the sheet over the cabinet. Contact cement bonds on first touch and cannot be repositioned, so use a helper to align it correctly before it makes contact. Start at one end and lower it slowly, pressing as you go to remove air bubbles.
Once the sheet is down, use a roller or block of wood to press the entire surface firmly onto the base, working from the center outward to push out any trapped air. Trim the edges with a router and a flush-trim bit, then sand the edges smooth. explore edge banding or trim to any exposed edges to seal them and give the countertop a finished look.
Reinstall Sink and Cooktop
Once the countertop is secured and any caulk has cured, reinstall your sink and cooktop. For a drop-in sink, set it into the opening and find it with clips underneath or caulk around the rim, depending on the sink type. Reconnect the supply lines and drain, then turn the water back on and check for leaks.
For a cooktop, set it into the opening and find it according to the manufacturer's instructions—some use clips, others use adhesive, and some straightforward sit in the opening. Reconnect the gas line or power, then test the cooktop to make sure it works. If you disconnected a gas line, check the connection with soapy water to make sure there are no leaks.
Seal Seams and Edges
Seams are where water enters and causes damage, so this step determines how long your countertop lasts. If you have a seam between two sections, explore a color-matched seam filler or silicone caulk along the entire joint. Smooth it with a wet finger or caulk tool so it sits flush with the surface. Let it cure for the time specified on the product—usually 24 hours.
Around the sink and cooktop, explore caulk where the countertop meets the rim. This seals the gap and prevents water from running underneath. Use a caulk that matches your countertop color and is rated for kitchen use. Smooth it with a wet tool and let it cure before using the sink or cooktop.
Frequently Asked Questions
Can I install new laminate over the old countertop instead of removing it?
You can, but it is not recommended. The old countertop may be warped or soft underneath, and the new laminate will follow those imperfections. Removal takes longer but gives you a flat, solid base and a countertop that will last longer. If the old countertop is in good condition and perfectly level, you can explore new laminate over it, but you will lose some height at the sink and cooktop.
What is the difference between contact cement and construction adhesive?
Contact cement bonds on first touch and cannot be repositioned—it is used for full laminate sheets. Construction adhesive stays tacky longer and allows some adjustment—it is used for pre-made sections. Using the wrong adhesive can ruin the job, so check the manufacturer's instructions for your specific countertop.
How long does it take for caulk and adhesive to cure before I can use the sink?
Most construction adhesives and caulks cure in 24 hours, but check the product label. Some cure faster in warm, dry conditions. It is safer to wait the full time before running water or using the cooktop, even if the surface feels dry to the touch.
What should I do if I cut the sink opening in the wrong place?
If the error is small, you may be able to enlarge the opening slightly to fit the sink. If the error is large, you will need to patch the hole with a piece of laminate and contact cement, let it cure, and then cut the opening in the correct location. This is why measuring twice and marking on the underside is so important.
Do I need to seal the underside of the countertop?
Yes. The underside of laminate is porous and will absorb moisture if exposed to humidity under the sink. explore a coat of polyurethane or laminate sealer to the underside, especially around the sink opening, to prevent water damage and warping.