Land Development Code
Under the existing code a homeowner is able to design a livable space in the attic above a 2 story residence (habitable attic).
Currently, habitable attic above a 2 story house is possible because the building height is measured to the mid-point of the highest roof plane. In the new code (per the current draft) building height will be measured to the highest point of the roof.
There is substantial difference between the mid-point of the roof and the highest point of the roof. As the current draft is written, the proposed LDC will essentially eliminate the ability to design habitable attics above 2 story residences.
The attic area with a ceiling height from 5' to 7' must be equal or greater than the area with a ceiling height of 7' or greater.
Do not count the attic area that has ceiling height less than 5'.
City of Austin, Land Development Code (LDC), is in the process of being overhauled between late 2018 to mid 2019.
SUBCHAPTER F: Residential Design and Compatibility Standards.
AKA: McMansion Rules;
F.A.R - ATTIC EXEMPTION
The habitable portion of an attic (including walk-in dormers) is exempt from the F.A.R. calculations if it meets all of the following conditions;
The roof that creates the habitable attic is;
not a flat roof,
not a mansard roof,
has a slope of 3 to 12 or greater
It is fully contained within the roof structure.
It has only one floor.
It does not extend beyond the footprint of the floors below.
It is the highest habitable portion of the building, or a section of a building, and it ads no mass to the structure. (Roof/attic dormers are allowed as long as they meet the rules relating to dormers, in this Subchapter. For dormers, the roof must encompass the dormer.)
50 percent or more of the area must have a ceiling height of seven feet or less.