A vessel sink, a sink that sits on top of a counter or vanity, can give a bathroom a uniquely polished look. Vessel sinks are nice because they can be installed on any flat vanity top. The top of the vanity can be granite, tile, Formica, or any other type of solid surface. Vessel sinks also give you the option of converting a dresser or other piece of furniture into a vanity for a customized look.
Drain holes and faucet holes will have to be drilled on any vanity or dresser top chosen for a vessel sink installation. Other considerations are the drain pipe location and countertop height. Setting a vessel sink on top of a standard height vanity would result in a sink that is much too high. The height of the vanity needs to be low enough so that the installed sink height is somewhere between 30-36”.
Also, keep in mind that if you will be using a piece of furniture that is not specifically designed for a vessel sink additional alterations may have to be made. These may include removing drawers and attaching only the faces to the cabinet to allow room for water and drain lines inside. The back of the dresser will most likely have to be opened for the water and drain line as well.
If you are installing a vessel faucet as well as a vessel sink you should install the faucet first. Since faucets are usually located behind the sink, it is easier to install them first. Taking the time to install the faucet first can give you more room to work in an already limited space.
Check the vessel sink you plan to install as it may come with special mounting instructions, but most are pretty similar.
Mounting a Vessel Sink above the Countertop
Before you begin, make sure you have the correct vessel sink drain. The drain in most installations serves as a drain as well as the anchor that connects the sink to the countertop. If the sink you bought has an overflow, then you will need to make sure you get a vessel sink drain with an overflow. A sink without an overflow will require a vessel sink drain without an overflow. Some sinks mount differently to the counter but the majority of the vessel sinks I have seen mount with the vessel sink drain only. This is all that holds the sink onto the vanity top. Note that glass vessel sinks will usually require a mounting ring that sits on the counter and holds the vessel.
- Position the sink. If the bottom of the sink you bought is flat, then you can usually mount the vessel directly onto the countertop. Align it with the drain opening in the countertop.If the bottom of your vessel sink is rounded, then you will need to use a mounting ring in between the countertop and the vessel sink. Position the mounting ring over the drain opening and set the vessel on the ring. The mounting ring is used to help securely hold and seal the sink to the countertop giving the rounded bowl a nice flat surface area to connect to the vanity top. The mounting rings come in any finish and can match your faucet trim.
Having a helper to hold the vessel sink is a good idea, particularly if it is a round bottom vessel. If you don’t have a second set of hands, you should hold the vessel with one hand while you anchor it the drain (step 2).
Note: Silicone can be used to secure the vessel to the counter when a gasket isn’t included.
- Connect the drain: Apply Plumber’s putty to the part of the drain that goes into the sink. Or if the drain comes with a foam or rubber gasket for the top that will work as well. Drop the top part of the drain into the sink making sure to center it and check that if there is any lettering, it is straight.Under the sink use pipe joint compound or some other sort of lubricant on the part of the rubber seal that sits on the sink or the countertop. Put the rubber seal onto the drain first and push it up as far as you can. After the rubber seal is in place, put the friction ring in place followed by the mounting nut. Hand-tighten the nut from under the counter until the sink is nice and snug. You can use pliers or similar tool to finish tightening the mounting nut but be very careful to not over tighten as this can damage the vessel sink. Check the alignment and lettering once again to make sure it is still straight.
- Connect the drain trap: Now that the vessel sink drain is installed up you can connect the trap to the drain. The 1 1/4” drain coming from the vessel sink should fit onto a 1 1/2” trap like any other normal lavy drain trap installation. This is done using a reducing washer to go from 1 1/2" to 1 1/4".
- Test for leaks: After all connections are made to test the drain thoroughly for leaks. First, run water into the sink and check for leaks under the sink. If there are no leaks under normal running conditions, fill the sink all the way up, so you give it a good volume test.