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Busch_League

Joined: Feb 19, 2014

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Howdy,
I am looking into building an ADU in Austin, TX and wanted to see if I built a 2-story ADU with a rooftop deck, would the deck count as a 3rd floor? The zoning only allows for 2 stories, and wasn't sure if putting up railing on the roof for a deck would classify it as a 3rd floor. Thank you!

dudeabides

Joined: Jan 2, 2016

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7:33a, 5/25/23

I'm not an architect, but according to the Austin Codes found here:

Quote:
503.1.4 Occupied Roofs. A roof level or portion thereof shall be permitted to be used as an occupied roof provided the occupancy of the roof is an occupancy that is permitted by Table 504.4 for the story immediately below the roof. The area of the occupied roofs shall not be included in the building area as regulated by Section 506. An occupied roof shall not be included in the building height or number of stories as regulated by Section 504, provided that the penthouses and other enclosed rooftop structures comply with Section 1511.
Exceptions:
1. The occupancy located on an occupied roof shall not be limited to the occupancies allowed on the story immediately below the roof where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and occupant notification in accordance with Sections 907.5.2.1 and 907.5.2.3 is provided in the area of the occupied roof. Emergency voice/alarm communication system notification per Section 907.5.2.2 shall also be provided in the area of the occupied roof where such system is required elsewhere in the building.

2. Assembly occupancies shall be permitted on roofs of open parking spaces of Type I or Type II construction, in accordance with the exception to Section 903.2.1.6.

3. An open noncombustible trellis or similar overhead shading device complying with the structural requirements of this code shall not be considered as a covering or roof provided that the trellis or shade has an evenly distributed net free area of 50 percent or greater.

503.1.4.2 Interstitial Spaces Beneath Rooftop Occupancies. When decks or other walking surfaces are constructed above a roof to facilitate rooftop occupancy, the space between the roof surface and the deck or walking surface shall be constructed in a manner that precludes the accumulation of material between the roof surface and the deck or walking surface and that prevents the introduction of ignition sources to the space, and allows for proper roof drainage.