Widespread faucets offer increased design latitude. Unlike center-set or fixed-base units, you can place the components 8 inches apart or more.
Consider countertop thickness before purchasing your faucet. Granite, marble, or other materials may be thicker than the thread length on many faucet bodies. You may be able to use a faucet extension kit for thick materials or countersink the mounting holes on the underside of the sink for short stems.
Sink styles matter, too. A drop-in sink with precast or precut mounting holes saves time and work, but an undermount sink allows you more freedom in placing the faucets and accessories in holes drilled in the countertop.
Installation of a widespread faucet follows the same general procedures as a center-set model. If working with a drop-in sink, you may be able to install all the faucet parts before installing the sink.
About 3 to 4 hours
Screwdriver, putty knife, adjustable wrench, slip-joint pliers, basin wrench, hole saw
Shutting off water, working under a sink, attaching plumbing parts
Install sink, drill faucet mounting holes if necessary
New faucet and accessories, plumber's putty or sealant
With a helper holding the unit from above, tighten the retaining nut, T-fitting, or whatever mechanical device secures the faucet to the sink deck or countertop. Some units require only hand-tightening. Others call for a faucet wrench. Tighten the unit, then center it in the hole.
Apply plumber's putty or silicone sealer to the spray-hose housing flange and insert the spray-hose housing in the deck or countertop. With a helper holding the housing from above, tighten the nut from below. Assemble the head to the spray hose and install the hose in the center outlet of the T-fitting.
Following the manufacturer's instructions, assemble the supply tubes and any other parts to the valve bodies. Seal the flanges with plumber's putty or silicone and insert the completed units in their respective holes. If the valve bodies feature straight copper pipes, install the valves with these pipes facing the outside of the sink. Tighten the mounting nuts.