Roof

The Roof is the fifth stage of Adventure Mode and takes place on the top of the player's house. It consists of a 5x5 sloped side in back and a 4x5 straight side in front with a satellite dish on the zombie side and a chimney on the player's side. Apparently, neither Crazy Dave nor the Cabbage-pult know how the Zombies got on the roof, but at the beginning of roof levels the player can see a ladder at the right that may have helped them.

Effects on the Game
Normal plants (Peashooters, Starfruit, etc.) will not be able to hit zombies if planted on the sloping side (although they can fire over the edge when planted on the first sloped column), so you will need to use lobbed-shot plants for this stage. You also need Flower Pots to place plants on the roof. Because it takes place during the day, Sun falls from the sky during this stage, and mushrooms fall asleep. There are no Lawn Mowers, so before purchasing Roof Cleaners from Crazy Dave, your last line of defense is, unfortunately, your hindmost plants. This stage also has "ambush zombies", which are actually Zombies (or Conehead Zombies and Buckethead Zombies) that are dropped by Bungee Zombies onto the roof, possibly into your defenses, although they can be repulsed by Umbrella Leaves. This is similar to the zombies that surface from the Pool and the zombies that come out of Graves.

New Plants
The plants added to this level are made especially made to fit the roof. For example, due to the slope of the roof, catapults must be used. These include Cabbage-pult, Kernel-pult, and Melon-pult, three plants essential to Roof levels. The other plants added in the Roof stage are Flower Pots, Coffee Beans, Garlics, Umbrella Leaves, and Marigolds.

Trivia

 * While it appears that the zombies may have gotten onto the roof with the ladder, the rungs are spaced too far apart for them to use.
 * It is unknown how Vehicle Zombies get up on the roof. However, they may have been dropped by Bungee Zombies.
 * Also, it is odd how Vehicle Zombies can fit in the chimney while still riding their vehicles.
 * The zombies will enter the house via the chimney if they got past the plants and Roof Cleaners.
 * The final level, level 5-10, features the Roof level at night.
 * The music played on the Roof is called 'Graze The Roof', a pun on the phrase "raise the roof".
 * Fume-shrooms are the only non-Lobbed-shot plants that can shoot up the slope of the roof.
 * During the Roof levels (especially level 5-10) it is unclear how the roof can suport all of the heavy zombies, most notably Gargantuars, Zombonis, and Dr. Zomboss's Zombot despite there already being cracks in the roof.
 * In the Xbox 360 trailer, it is said that the roof tiles are Spanish.