What are the Guidelines for Modeling an ADU (Accessory Dwelling Unit)?

When modeling an ADU, there are several circumstances to consider.

In the case of an attached Garage conversion, this is considered an Addition, and the floor space of the Garage is input as New (no it is not an Alteration).  See our example file “Existing+Alterations+Addition.bld” for an example.  Note in this case, the code does allow for the “Existing Wall w/Siding” selection to be used, listed under the wall input.

In the case where they are adding square footage to an existing home, it is treated the same as the Garage conversion, and you may be able to claim the “Wall Extension” selection, also given under the wall input.

In the case of an existing building (garage, shed), not attached to the home, this is also an Addition as described above, and also qualifies for the “Existing Wall w/Siding” provided the siding remains.  Also, any type of Addition to this same structure is still an Addition to the main house.  Existing Floor area, where required, should be for the main house.

In the case of a New building on the site, this is now input as New, and the ADU designation is not relevant.  It is a new home, and will be documented as such, and the output will not indicate ADU.  This circumstance will also require a PV system be installed.

In ALL cases, an ADU will require an IAQ fan, verified in the field by a HERS rater.

Categories: 4. Lowrise Residential Title 24

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