"Room on the 3rd Floor" was written by band members Tom Fletcher and Danny Jones. The song is less upbeat and uptempo than their previous singles. It was written during Fletcher and Jones' two-month stay at the InterContinental London (Room 363), which they found a little tedious; they began listening in to arguments in the neighbouring rooms, and wrote about a rather annoying room-service maid, all of which are mentioned on the track.
The video depicts the band as small plastic models (based on Tamiya models). During the shoot, the band were painted blue ("Like a smurf"- Danny) and then digitally enhanced to make them look like plastic. McFly can be seen in full colour playing on the packaging box; the McFly Set with Roadie and Fans is a nod to their then upcoming tour.