How to seal kitchen sink drains: Professional tips for the DIYer

Find water under your sink? You likely don’t need a plumber, easily learn how to seal the kitchen sink drain yourself. Stop those slow leaks and the resulting mess and damage. Our directions make it simple.

Sealing your sink drain is a critical component to your household maintenance. This simple upkeep will help prevent costly water damage from occurring and can even contribute to improved indoor air quality by reducing mould and mildew buildup. 

The two most popular ways of sealing a kitchen sink drain are with plumber’s putty or with silicone sealant. Our recommendation is silicone. While plumber’s putty is effective, silicone is more waterproof and durable than putty. It  has strong adhesive qualities, which help keep the drain flange in place. Silicone is also very easy to use and clean up.Another advantage of silicone and silicone-fortified acrylic sealants is that they are very versatile. These same products can also be used to seal the seams around the edge of the sink, the backsplash, and corners. 

LePage 2 in 1 Seal & Bond Kitchen & Bath Silicone is one of the best products available to replace caulking around kitchen sinks and other fixtures in the kitchen and bath. It is formulated for these high-moisture areas and functions as both a sealant and a powerful adhesive, resulting in long-lasting durability while being highly effective at preventing mould and mildew. It cleans up easily with just water and a clean cloth and dries fast in only two hours.

Need a paintable sealant? LePage has you covered. LePage 2 in 1 Seal & Bond Kitchen & Bath Adhesive has the same qualities as the Express Silicone formula above, but in a paintable acrylic. This adhesive sealant forms a flexible, durable bond that is mould resistant and can be painted after just 40 minutes.

Before beginning, gather the tools and items listed below:

• sealant and caulking gun 
• water, mineral spirits, and clean cloths
• a pipe wrench for metal drains or channel-lock pliers for plastic or PVC fittings
• utility knife
• safety glasses and gloves

Once you’re ready, proceed as follows to seal your kitchen sink drain:

1. Remove the drain flange by loosening the large nut on the bottom side of the sink. Unscrew it to separate the flange on the inside of the sink from the fastener underneath. Move the drain pipe to the side if possible.
2. Clean the flange with soap and water or household cleaner. Carefully scrape away any old sealant or putty from both the flange and the sink drain hole.
3. Open the tube of sealant with a putty knife by cutting the nozzle at a 45° angle. Use a nail or a piece of wire to puncture the foil seal inside the nozzle of the tube. Place the tube into the caulking gun. Be sure to use a LePage 2in1 Seal & Bond for best results.
4. Apply silicone all the way around the drain hole or evenly to the bottom of the flange. 
5. Reseat the flange into the drain hole with light pressure. A small amount of silicone sealant should squeeze out around the edges of the flange. This is normal and indicates that you used sufficient material.
6. Keep hold of the flange from the top while you begin to reattach the underside. Make sure the flange is seated properly in the sink before tightening down.
7. Wipe away any excess silicone with a towel dampened with water or mineral spirits.
8. Reconnect the drain pipe loosely. Allow the silicone to dry before tightening to full torque.
9. Tighten the drain pipe and flange assembly and check for leaks. A good way to do this is to fill the sink with water (with the stopper closed) for about 10 minutes. Check for dampness or dripping under the sink, take note if the water level goes down while the water is in the sink.  If so, tighten the parts a little more.