Accessory Dwelling Units & Tiny Houses

The Petersburg Borough Assembly adopted amendments to the zoning code creating standards for tiny house dwellings, detached accessory dwelling units, and multiple residential buildings on one lot. 

PRADU Program

The Petersburg Borough is excited to announce our new Permit-Ready Accessory Dwelling Unit (PRADU) Program!

This program is designed to streamline the process of adding an ADU to your property. Here's what you need to know:

Pre-approved Plans: We're offering four different ADU models, ranging from cozy 390 square feet to spacious 650 square feet. These plans have already been reviewed for compliance with building code, saving you time and money on the design and permitting process. Additionally, the borough will waive the standard plan review fee.

Locally Designed: Each model was created by talented local architects, ensuring they fit the unique character of our community.

Versatility: These ADUs can function as standalone dwellings or complement your existing single-family home.

Peace of Mind: The complete building plans include everything you need to get started, ensuring your ADU meets all local building codes.

Learn more...


Tiny House Dwellings

A tiny house dwelling is a one-family dwelling unit on a permanent foundation that is 400 square feet or less in floor area, excluding lofts. 

The Petersburg Borough adopted the 2018 IRC Appendix AQ: Tiny Houses standards to allow certain exceptions to the adopted building code for tiny houses. Tiny houses, constructed and inspected to the IRC standard, may be placed on a permanent foundation in any zoning district where single-family dwellings are allowed.

Tiny houses on trailers/wheels are not considered legal one-family dwellings and are classified as a motor home or RV. Mobile homes, manufactured homes, RV's are not an allowed use in single-family residential areas. Please contact the building official for information about where tiny houses on wheels are allowed.

Please note construction of a tiny house requires a building permit and must meet borough building code standards, including insulation standards. If the tiny house is built off-site, the owner will need to provide documentation that the dwelling was inspected and approved by an ICC-certified inspector for building, plumbing, and electrical systems. 

Please contact the borough building official for more information prior to constructing or purchasing a tiny house dwelling. 

Appendix AQ: Tiny Houses

Building Permit Application


Detached Accessory Dwelling Units (ADU). 

Borough code already allows duplexes on single-family residential lots as a by-right principal use. In other words, most residential property owners already have the right to construct a second dwelling unit on their property (the exception being Rural Residential zoning), however the second dwelling had to be attached by a common wall to the primary dwelling. 

In an effort to increase flexibility of ADU’s but still maintain the character of our residential neighborhoods, the code was amended to establish “detached” ADU standards.

The standards require the accessory dwelling unit to meet adopted building codes, be a subordinate structure to the main house, be located on lots that are large enough to accommodate a second building while still meeting the lot requirements for the district (yard setbacks, maximum lot coverage, off-street parking, etc.) and not require a variance from the lot requirement standards. A building permit is required to construct an ADU.

Please contact the borough building official for more information prior to constructing or purchasing a detached ADU, or converting an existing structure to an ADU. 

Detached ADU standards

Building Permit Application


Multi-family Housing. 

The code amendment approved by the assembly allows for multiple one-family, two-family, or multi-family dwellings to be located on one lot.

The development requirements and lot standards for the district remain the same. This would provide property developers with more options to best meet market demand for housing on multi-family lots, for example constructing three or more cottage houses on one property.

Please contact the borough building official for more information regarding multi-family housing developments.