How to Install a Sink

Skill Level:Ambitious to expert

Time:8 hours total - 2 hours work, 6 hours interval

Regardless of the material you have chosen for your counter, some general rules apply when you install a sink. Surface mounted sinks are generally installed with caulking and clamps; self-rimming porcelain sinks need only caulk but self-rimming stainless steel sinks add clamps as well. Recessed sinks, where the unit is set on the plywood base, are most commonly used with tiled counter tops. Porcelain and cast iron are the recommended choices for recessed installation. Stainless steel, tile and grout have different rates of expansion and contraction and are therefore avoided together, but double walled stainless can be used in some cases.

TIP:Our plumbing consultant Wayne McCarthy adds, "Porcelain, Cast Iron, and Enameled Steel self-rimming lavatories should all be mounted with a good latex based caulking. The caulking comes in a variety of colors to better match your countertop or lavatory. When installing kitchen sinks the same applies, but not for stainless steel sinks. Stainless steel sinks should have plumber's putty put under the flange instead of caulking. Put enough under the flange to allow it to expand and ooze out when you tighten the clamps.

Step 1 - Trace the Template onto the Countertop

Most sinks and lavatories come with templates in or as part of the box. Using the templates makes life easier. The most common mistake is not cutting the sink opening the proper dimension or not lining up the opening with the sink base cabinet. Carefully position the template on the newly laminated countertop or the plywood base. Try to center it but leave at least 1 ½-inches and not more than 3 inches from the edge of the counter. Draw a pencil line around the edge of the template. Your template should be for the proper size of the hole, not the overall size of the sink and flange. If it's not, measure inward½-inch, and draw another line inside of that sink line. Be sure of your marks.

TIP:Wayne reminds you, "Double check all your dimensions before cutting the counter top. If installing a stainless steel sink, make sure you have enough room for the clamps under the counter."

Step 2 - Cut out the Sink Hole

Drill a hole large enough for a jigsaw blade to the inside of each corner of the inside line. Cut along the inside pencil line with your jigsaw while another person supports it from below. Then lift that waste piece out.

Step 3 - Install the Faucets

Individual faucets will have manufacturer's instructions to follow. Some are mounted through the holes in the sink using plumber's putty. Some require separate holes drilled through the countertop. Either way, it is easier to put the faucet and strainer(s) on before the sink is installed. An adjustable wrench works well to tighten up the hardware that holds the faucet in place.

Step 4 - Install the Supply Lines

Supply line connector kits are available that contain the flexible chrome pipe, hardware, shutoff valves and instructions. You need to specify the diameter and material of the supply pipe and whether or not you will be adding a dishwasher. The dishwasher requires a special T-shaped shutoff valve.

Step 5 - Install the Basket Strainer

Pack the basket strainer with plumber's putty and push it firmly down into place. Where the strainer is threaded underneath, slips on the washer and then tighten down the lock nut until the putty oozes out. Clean off all excess putty.

Step 6 - Caulk and Install the Sink

Place a bead of caulk along the entire bottom edge of the upside-down (self-rimming) sink. Position it carefully over the opening and press it down until excess caulk oozes out along the edges. Follow the manufacturer's instructions for any additional hardware that comes with or the sink.

Use Plumbers Putty for Stainless Steel sinks instead of caulking. Put a good amount under the lip or flange of the sink, as any excess will ooze out and can be removed with a putty knife after the clamps are tightened. When using latex caulking on other types of sinks, have a container of clean water and a clean sponge or rag available for wiping the caulk around the edge of the sink. You may have to add some more to get a nice even bead around the edge.

TIP:Wayne suggests, "After the sink is set and caulked place two 1-gallon containers of water in the sink to hold it down until the caulking dries. Allow at least 4 to 5 hours for the caulking to cure before hooking up the water and drain."

Step 7 - Install the P-Trap

Install the P-trap next by connecting the tail piece to the basket strainer using a slip nut over a washer. Then connect the P-trap to the tail piece with another washer and slip nut. Attach the P-trap to the wall stub-out with a curved drain extension pipe. If it is a two bowl sink you will need an End Outlet Waste to connect the two bowls into one drain.

TIP:Wayne says, "After the drains are hooked up fill the sink and check for leaks around the strainer(s)."

Wayne McCarthy, professional plumber, contributed to this article.