A kitchen sink with a drainboard is a practical upgrade for busy kitchens because it combines a full-size basin with a sloped drying area that channels water back into the bowl. The key difference from a standard sink is the drainboard section: it must be supported evenly, sealed carefully along its long edges, and installed with the correct slope so water does not pool. This guide focuses on a typical top-mount drop-in installation, which is the most common for stainless steel sink-and-drainboard sets.

Before You Start: Confirm Fit, Orientation, and Support

Start by checking three things before cutting or installing anything.

First, confirm orientation: decide whether the drainboard will be on the left or right based on your workflow and faucet position. Second, confirm cabinet compatibility: Drainboard Sinks are longer than regular single-bowl sinks, so you need enough countertop length and a cabinet that can support the basin and the drainboard section. Third, confirm the faucet and accessory holes: many stainless steel sinks come with pre-punched positions; plan your faucet, Soap Dispenser, and sprayer placement to avoid conflicts.

If you are sourcing stainless steel sink-and-drainboard options for projects or bulk orders, you can review LANSIDA’s kitchen sink range at LANSIDA for product selections and manufacturing capability.

Tools and Materials Checklist

Use the table below as a quick prep list.

Step 1: Dry-Fit and Mark the Cutout

Place the sink upside down on the countertop and center it over the cabinet. Ensure the drainboard section sits where you want it and does not interfere with backsplashes, walls, or nearby appliances.

Most sinks include a cutout template. If you have a template, tape it down and trace it. If you do not, trace the sink rim and then draw an inner cut line so the rim still rests on the countertop. A common approach is to move the cut line inward so the rim overhangs the cut by roughly 10 to 15 mm, but always follow the sink’s real rim width to avoid over-cutting.

Step 2: Cut the Countertop Opening Cleanly

Drill a starter hole inside the cut line large enough for your jigsaw blade. Cut slowly and keep the saw base flat to prevent chipping. Support the cutout piece near the end so it does not snap and damage the countertop edge.

After cutting, test-fit the sink again. The sink should drop in smoothly without force, and the rim should sit flat around the entire perimeter, including along the drainboard side.

Step 3: Install the Drain Assembly Before Dropping In

It is easier to install the basket strainer and drain parts while the sink is outside the countertop.

1. Apply plumber’s putty under the basket strainer flange.

2. Insert the strainer into the drain opening.

3. From below, install the gasket and locknut, then tighten evenly.

4. Wipe away excess putty at the top.

If your sink includes an overflow or additional drain connections, assemble them now and make sure every gasket seats evenly.

Step 4: Apply Sealant to Prevent Leaks at the Rim and Drainboard Edge

Turn the sink right-side up. Apply a continuous bead of kitchen-grade silicone under the rim where it contacts the countertop. On a drainboard sink, pay extra attention to the long drainboard side and corners because these areas see frequent splashes.

If the drainboard will sit near a wall or backsplash, seal that joint as well after final placement to stop water from wicking behind the counter.

Step 5: Drop In the Sink and Lock It Down Evenly

Lower the sink into the cutout carefully to avoid smearing the sealant. Press down around the rim to seat it. Confirm the drainboard section sits flat and feels supported. If you notice rocking, do not continue. Lift the sink, correct the cutout or support points, and reset it.

From inside the cabinet, install sink clips according to the sink design and tighten gradually in a cross pattern. This prevents warping the rim and helps maintain an even seal. Do not overtighten, especially on stainless steel, because excessive force can distort the rim and create gaps.

Step 6: Connect the Water Supply and Drain Plumbing

Reconnect the faucet supply lines to the shutoff valves and tighten securely. Use Teflon tape on threaded fittings where required, but do not tape compression fittings unless the manufacturer instructs it.

Install the P-trap and drain pipe:

• Keep the trap directly below the drain outlet.

• Maintain a slight downward slope from the trap arm to the wall outlet so water flows smoothly.

• Avoid sharp angles and long horizontal runs that can trap debris.

Once connected, run water for several minutes and check every joint with a dry paper towel to spot slow leaks.

Step 7: Water-Test the Drainboard and Final Seal

A drainboard should guide water back into the basin. Test it by splashing or pouring a small amount of water across the drainboard surface and observing the flow path. If water pools at the outer edge, confirm the sink is fully seated and the countertop is level. Minor pooling can sometimes be improved by ensuring the clips are evenly tightened and the rim is fully compressed into the sealant.

Finish by applying a neat silicone bead along the back edge where the sink meets the backsplash or wall, then smooth it to a clean line. Allow the sealant to cure according to the label instructions before heavy use.

Common Installation Mistakes to Avoid

• Cutting the opening too large so the rim cannot fully cover the edge

• Skipping dry-fit alignment, leading to an off-center drainboard

• Using too little silicone along the long drainboard side

• Overtightening clips and deforming the rim

• Misaligning the trap arm and creating poor drain slope

A Practical Note on Stainless Steel Drainboard Sinks

For long-term reliability, stainless steel thickness, rim stiffness, and consistent surface finishing all matter because the drainboard section sees frequent loading from dishes and cookware. If you are comparing options for renovations or supply, LANSIDA provides stainless steel sink solutions that can fit different kitchen layouts and project needs. You can explore their product information at LANSIDA.