Before removing the old pedestal sink, shut off the hot and cold water supply lines. Use an adjustable wrench to disconnect the supply lines from the hot and cold stops. Have a bucket and rag close by to catch any drips.
Unscrew the collar nut from the drain line and gently disconnect the p-trap. Unscrew the lag screws from the wall using a socket wrench. Carefully remove the old sink from the pedestal; remove the base and p-trap assembly to make room for the new vanity. Clean up any spills or debris before caulking any holes left from the lag screws.
Place the template on top of the vanity and cut the hole, keeping in mind that ours is an 8" faucet, which means it's 8" across; make sure the new sink is big enough to accept an 8" faucet. Since these holes are 8" across, from here on, it will be a very simple process to take the faucet and pop-up assembly off this sink and transfer it to the new sink.
Begin by using a pair of slip-joint pliers to remove the drain body from the pop-up assembly. Unscrew the metal nut from the drain flange and remove the stopper and any plastic washers. With all nuts and washers removed, the drain flange should come out easily.
Use slip-joint pliers to loosen the water supply lines connected to the faucet handle bodies (Image 1). Loosen the metal nut on the faucet handle bodies and remove them from the sink. Remove the water supply hoses from the supply tee; use slip-joint pliers to loosen the connections.
Finally, remove the spout body by unscrewing the supply tee and the metal washer from the spout shank (Image 2).
Thread the supply tee onto the spout shank and tighten it down, making sure the arms of the tee are aligned to face the left and right sides of the lavatory. Insert the valve bodies into the proper mounting holes and securely tighten the locknuts. Make sure the valve body marked "cold" is installed to the right of the spout. Attach the water supply hose to the supply tee and tighten the connection with slip-joint pliers. Repeat the process with the hot water valve body. Be careful not to kink the supply hose, and remember: there's no need to use plumber's putty to connect the hoses to the supply tee.
Apply a ring of plumber's putty to the underside of the flange before inserting it into the lavatory drain hole. Attach the washer and gasket to the flange and partially thread the nut to the flange. Tighten the nut and remove any excess putty.
Screw the drain body to the flange after making sure the pop-up assembly will face the faucet. Insert the stopper and screw the pop-up bar onto the drain body (Image 1).
Connect the stopper assembly to the stopper bar using the connecting rod (Image 2).
Finally, attach the water supply lines to the hot and cold valve bodies. Use two wrenches to tighten the lines.
The vanity base has to be mounted directly against the wall to find the main brace; locate the wall studs and screw the brace directly into the studs. Then you can put the top on and complete the plumbing.
Locate the area of the baseboard that needs to be removed and mark it with a pencil.
Remove the vanity from the wall and use a flat saw to cut the baseboard. Use a razor knife to loosen the baseboard from the painted wall; use a large flathead screwdriver and a crowbar to pry the baseboard loose. Locate the wall studs with a stud finder and mark the location with a pencil.
Slide the vanity back into place and secure it to the wall using woodscrews. Place a bead of latex caulk around the top edges of the vanity and carefully place the china sink on top. Let the caulk dry completely; it usually takes 12 to 24 hours.
When the caulk is dry, attach the hot and cold water to the corresponding supply lines underneath the sink, making sure to tighten them with a wrench.
Finally, connect the p-trap to the drain by screwing it in place using the threaded connection. Use the threaded fitting to secure the other end of the p-trap to the tailpiece of the drain assembly.
Installing a new vanity sink can cost as much as $1,000 and should take about a day to complete. If you are purchasing a vanity from a home center or local supply house, most will come pretreated with a coating that will protect the top from water damage. If you are retrofitting an antique cabinet, however, you will need to seal the wood around the sink to prevent splashed water from destroying it over time. Water sealers are available at home centers; brush on an even coat, making sure to follow the manufacturer's instructions.
Applying a bead of caulk or sealant around the edge of the sink will help keep water from leaking in around the sink and getting into the finish of the wood, which can rot over time. Apply a caulk bead all the way around the edge of the sink; take a finger and go around the edge, smoothing the sealant down. Don't worry if it's a little messy: a damp sponge will smooth the finish.
When it comes to protecting wood, there is also a protective pour-on polyurethane cover that can be mixed and poured on the countertop. It self-levels. Dry it by gently blowing on it or using a hair dryer.