In The Sims, a roof is automatically generated when an area is enclosed by walls. Players can select a roof pitch and roof texture, which will be applied to all roofs on the lot. Roofs in The Sims are mostly aesthetic, since there is no weather in the game.
The Sims 2Edit
In The Sims 2, there are several types of roof to choose from. The base game has hip, gable, 3-Hip and Half-Hip roofs, and flat roofs. Other expansions add domes, cones, octagons, pagoda-style roofs, and mansard roofs. All of these, except for the mansard roof, are available in the Roof section of Build mode. Mansard roofs are made by using pieces found in the Architecture section.[TS2:M&G] Flat roofs use flooring. Roofs can be automatically created, or be manually built and adjusted by the player. As the "auto roof" feature can replace existing roofs, there is also the option to preserve existing roofs to prevent auto roof from modifying them.
Roof pitch for non-flat or mansard roofs is set at 45 degrees, but can be adjusted to between 15 and 75 degrees using the roofslopeangle cheat (if The Sims 2: Nightlife or a later expansion is installed). Mansion and Garden Stuff allowed roof angles to be changed individually without the use of cheats.
Roofs are particularly important in The Sims 2: Seasons, as they keep the elements out. Greenhouses will also require their own unique roofs to allow the plants inside to continue growing during the winter.
The Sims 3Edit
The Sims 3 re-introduces auto-roofing, though it can be disabled. The roof tool in The Sims 3 mostly expands on the roofing options from The Sims 2, and allows the adjustment of roof pitch without the use of a cheat, a feature previously available in The Sims; The Sims 3: Ambitions (as well as an update for the base game)  allow the adjustment of pitch of individual roof segments. The Sims 3: World Adventures allows a roof type with pagoda-style eaves. Roofs, like in The Sims 2: Seasons, is essential to keep the out the elements from the weather in The Sims 3: Seasons.
The Sims 4Edit
The Sims 4 revamps the roof system completely. Auto-roofing has been removed, and instead roofs can now be pushed and pulled to the size and shape the player wants it to be. The base game has gabled, half gable, hipped, and half hipped roof styles, along with their diagonal versions. With the push and pull mechanic, roofs can also be shaped into different styles such as domed, pagoda, awning, and gambrel. Pentagonal, hexagonal, octagonal, and round roofs were added in Patch 57 along with an advanced curvature mode, eaves for the gabled and hipped roofs, and other customization options. Patch 68 also added six different glass roofs.
In The Sims 4: Seasons, roofs are now more important for houses, as they keep out the various elements of weather.
Use of space under/inside a roofEdit
In The Sims 2 and The Sims 3, it is possible to utilize space underneath a roof, provided that there is at least one story's worth of clearance between the rooftop and the surface below. Roofs built in the game have a 45-degree pitch by default; at this pitch, a roof goes up by exactly one full story for every three floor tiles it goes inward. So, for example, if a standard gable-style roof was built 10 tiles wide at the default pitch, the four centermost tiles under the roof would be usable space.
It is possible to adjust the pitch of a roof (using either the 'roofslopeangle'[TS2:NL] or 'individualroofslopeangle'[TS2:P] cheats) such that more or less of the space underneath it becomes usable. A steeper roof with a higher pitch makes more floor space under the roof usable, while a shallower roof with a lower pitch makes less floor space usable. When adjusting roof pitch in this way, it can be difficult to make multiple segments of the roof appear flush with other segments, since different segments might be set to different pitches. This is especially problematic if roof segments are on different stories of the building. Even if both segments of a roof are set to the same pitch, the segments may not align in a seamless way.
This issue can be solved by setting the pitch such that the roof will extend upwards by exactly one story, while extending outwards in an exact floor tile increment. The following formula can be used to solve for this problem:
- tan-1(rise÷run) = pitch (in degrees)
"Rise" indicates the distance between the top and bottom of a roof segment, and "run" indicates the distance between the left and right sides of the segment. A full-sized wall segment is three times as tall as a floor tile's width, so in most cases, the "rise" in the formula will equal three. The following is a list of angles (rounded to the nearest hundredth) produced by whole numbers input into the above formula:
- tan-1(3÷1) = 71.57°
- tan-1(3÷2) = 56.31°
- tan-1(3÷3) = 45° (this is the default)
- tan-1(3÷4) = 36.87°
- tan-1(3÷5) = 30.96°
- tan-1(3÷6) = 26.57°
- tan-1(3÷7) = 23.20°
As an example, if a player wanted to build a roof that went up one full story for every 4 tiles inward, the player would need to adjust the roof pitch to 36.87 degrees. This angle would ensure that the roof segments between stories would be seamless and even.