Installation guide : How to install an undermount sink
We always recommend consulting a professional if you are not familiar with installing plumbing fixtures and/or sanitary equipment.
Follow the steps below to install your new undermount sink.
First, here’s what you’ll need for the installation:
- Pencil
- Soft cloth
- Sandpaper
- Denatured alcohol
- Silicone sealant
- Mineral spirits
Step 1: Prepare the surface and shut off the water supply
Before beginning the installation, ensure that the water supply is turned off and all plumbing connections are disconnected.
Carefully turn the vanity top upside down on a stable, protected surface to prevent any damage. Unlike a drop-in sink, an undermount sink requires a precisely cut opening to fit its dimensions perfectly.
Smooth the edges of the cutout with sandpaper to prevent any damage to the sink. Then, thoroughly clean the surface and the cutout area with a clean cloth and denatured alcohol. Allow the surface to dry completely before proceeding to ensure proper silicone adhesion.
Step 2: Position the sink
Place the undermount sink over the opening, ensuring it is properly centered with the faucet hole and evenly spaced between the mounting points. A precise alignment is crucial before moving on to the next step.
Step 3: Trace the sink’s outline
Once the ideal position is determined, use a pencil to trace the sink’s outline onto the underside of the vanity top. This guide will make the installation easier.
Step 4: Apply silicone
Remove the sink and, while keeping it upright, apply a generous and even bead of silicone around the perimeter of the rim.
Clean the edge of the cutout again with denatured alcohol to remove any dust or impurities, ensuring optimal adhesion of the silicone.
Step 5: Install the sink
Carefully place the sink upside down into the opening, aligning it with the traced outline. Press firmly to ensure the silicone is evenly distributed.
If the sink is lightweight, use a weight or ask another person to help hold it in place during installation.
Step 6: Secure the clips and bolts
If mounting clips are provided, place the long end of the bracket against the sink’s rim. Insert the wing bolts through the brackets and tighten them securely.
Before fully tightening the clips, adjust the sink’s position to ensure it is perfectly aligned with the cutout. This must be done before the silicone starts to set.
Step 7: Flip the vanity top and check alignment
Once the silicone has completely dried, carefully flip the vanity top with the attached sink. Check that there are no gaps between the undermount sink and the vanity top. If any gaps are visible, tighten the mounting clips further.
Step 8: Remove excess silicone and let It cure
As the sink is pressed into place, some silicone may squeeze out along the edges. Wipe off any excess immediately before it hardens, using a damp cloth or mineral spirits.
Allow the silicone to cure according to the manufacturer’s instructions (up to 24 hours) before installing additional fixtures such as the faucet and plumbing connections.
