Shay's Apartment

Shay’s Apartment is where most of iCarly takes place. It is a three-story apartment with a private elevator in Bushwell Plaza, apartment number 8-C.

The first floor, which rests on the eighth floor of the building, has a living room with a connected kitchen (with a fully functional sink with real plumbing on set). Spencer's Room is on the first floor as well, near the Shays' bathroom. Spencer likes to call his bedroom "the Chamber of Awesomeness" and has adorned it with random decorations, as shown in a gallery on iCarly.com.

The stairs along with the cargo elevator are both located towards the back of the apartment.

The second floor, the building's ninth floor, never seen on-screen until iGot a Hot Room, houses Carly's bedroom. There is a second bathroom on the second floor, mentioned in iGive Away a Car, iHave My Principals (Carly has taken showers in both episodes), and in iPie, where Sam locks herself in the bathroom to eat a piece of pie, and is finally seen in "iToe Fat Cakes". The possibility of other rooms is also open.

The third floor, the building's tenth floor, is better known as the iCarly studio. It is also known to be a sort of space behind the studio, where iCarly guests wait to be introduced onto the show.

The apartment also comes with its own "built-in" cat, who's currently stuck behind the wall. This cat was only mentioned once.

Sometime during the mid to late 2010s, all of Bushwell Plaza including the Shay apartment was remodeled. It now features more exposed bricks, as well as metal doors instead of wooden ones. Spencer continues to live in the apartment and it is mentioned that he now owns it outright instead of renting it.

Trivia

 * The Shays' living room is decorated with collections of insulated drink containers, older model transistor radios, stereos and telephones and models of gummy bears. There is no mention as to which family member collected these items, though it is likely that it was Spencer, who could have found the items at the junkyard.
 * The chain lock on the Shays' apartment front door has been broken several times, and it was even missing in the episode iPromise Not To Tell. However, in the first part of Season 1, there was no chain lock on the door at all.
 * The Shays' downstairs bathroom has never been shown in the series.
 * Perhaps the oddest item in the living room is a yellow diaper pail of the sort used to soak cloth diapers prior to washing, that sits close to front door of the apartment. In "iStakeout" Carly uses this pail to clean up trash left by the cops.
 * On a shelf in the kitchen is a "cookie time" cookie jar that appears identical to one that was used on the set of "Friends" for many years.
 * In the kitchen, most of the fridge magnets appear to be different in every episode.
 * In between the living room and the kitchen is a counter which usually has two red bar stools of the same type as those used in the Groovie Smoothie, except in "iWant More Viewers" and "iWant a World Record" and "iPie", when there are three red stools. In "iPsycho" Spencer purchases a granite counter top to replace the broken wooden one, but it completely crushes the counter. However in subsequent episodes the counter was rebuilt with its original wooden top and the granite top was never used, which seems odd given that granite counter tops are quite expensive.
 * It was mentioned by Dan Schneider that Spencer's room after iChristmas was rebuilt to be Carly's new bedroom.
 * The Shay kitchen appears in the Hungry Girl videos Chew & Tell #85, Emergency Snacks, Unrealistic Servings, Lord of the Onion Rings and Fun With … The Hungry Girl Book.
 * The TV in the Shay loft's living room changes from an older CRT-style TV to a more modern plasma TV between Seasons 1 and 2.
 * As of the revival, Spencer still lives here but it has been remodeled. He is mentioned to now own the apartment, not just rent it.

Speculation
It is unknown if every apartment unit in the building has three floors. It is speculated that each unit does not have three floors, as Marty Klemish lives in 7-C, directly below the Shay's residence. It is assumed that his apartment unit only has one floor. Because of this, it can be speculated that the Shays' apartment is special in comparison with the other apartment units.

Credits to

 * iCarly Wiki on Fandom