Data, assumptions & limits
Physical potential and a partial current-rule screen. Final zoning eligibility and building approval require review.
How a candidate is identified
The automatic search tests rectangular footprints on a 5-foot centre grid and at several rotations. It uses a 5-foot minimum inside parcel lines and 5 feet from mapped structures. The code specifies separation from the principal building; this conservative screen applies that gap to all mapped structures because the dataset does not identify the principal building. Front-yard setbacks require separate review. Only parcels with an existing mapped structure enter the candidate totals. The search can miss a placement that fits, especially on irregular parcels.
The footprint overlay can be moved and rotated manually. Green means the footprint meets these two geometric assumptions on the mapped data only. Roof overhangs, terrain, driveways, emergency access, utilities, easements, wetlands and flood hazards are not modelled. Internal or garage conversions are outside the detached-footprint counts.
Current-rule comparison
Reviewed November 10, 2026. The comparison checks the city’s standard 5,000 sq ft threshold for a new detached ADU against the area in the published parcel dataset. This is not a surveyed lot determination. Smaller lots can have other routes, including existing-footprint conversion and disability accommodation. Neither is modelled in the detached-footprint totals.
East Providence §19-181 provides for one ADU per lot, size limits related to the main dwelling, parking conditions and shared utilities. §19-144 sets a 5-foot separation from the principal building unless attached, a 5-foot lot-line minimum for eligible side/rear-yard accessory structures, and a 20-foot detached accessory height cap. Front-yard requirements still apply. §19-145 sets a combined building-coverage cap of 20% in R-1 and 25% in R-2–R-6, with total impermeable-surface caps of 40% and 45%, respectively. The ADU shares these allowances with existing buildings and surfaces. The placement screen uses the same 5-foot boundary minimum in both views; it cannot identify front lot lines or the principal building. Coverage uses mapped structures clipped to the parcel plus the selected new footprint, not surveyed coverage. No new footprint is added for the existing-footprint conversion route. Additional new paving must be included in final review. The tool does not have verified parcel zoning, frontage, main-home floor area, existing ADU records or parking data. It therefore does not declare a parcel legally allowed. User-entered facts refine only the listed checks. An unchecked rule is not counted as a failure.
DIY budget, policy tests and saved plans
DIY fields are user assumptions. Cash includes materials/fees, hired work and the entered contingency. Own labor hours are reported separately and do not add to cash investment. A blank amount is unknown, not zero. All budget categories need both amounts entered before the itemized total is used in ward investment scenarios.
Policy tests change only the stated minimum lot area, a uniform inward parcel distance and a mapped building-coverage cap. They retain a 5-foot gap from mapped structures and the same sampled rectangle-search method. The base comparison uses a 5-foot boundary minimum with no lot minimum or coverage cap. Policy counts are hypothetical geometry screens, not current-law eligibility or predicted construction. A zero lot minimum changes only that variable; it does not import Barrington’s other rules.
Saved plans download to the user’s device. They store the selected parcel, position, assumptions and entered facts. Printing includes a schematic footprint diagram and unresolved questions. Maps and records are dated and are not surveys.
Source data
Only matched residential lot outlines are included. Condominium units are not counted as separate physical lots. New subdivisions and unmatched records need review. Parcel boundaries are not surveys.
Costs & investment
The $125,000 / $150,000 / $175,000 scenarios are editable planning assumptions informed by NE Tiny Homes’ published 500 sq ft turnkey range. See also the RI Executive Office of Housing factory-price compilation. These are not local quotes. A 600 sq ft unit may require a larger budget.
Home Depot prices are listed shed or kit prices observed November 9, 2026. Availability, delivery, assembly and inclusions vary. These products are sold as storage buildings; no residential suitability has been verified. The tool adds only the additional completion allowance you enter. It does not treat a shed purchase as a completed home.
Additional homes equal candidate parcels × participation, rounded to whole units separately by ward. Investment equals those homes × the entered completed-project allowance. Construction spending is not added assessed value, tax revenue, local economic impact or net fiscal benefit.
Prepared November 2026. Map tiles: OpenStreetMap contributors; aerial imagery: Esri and its providers.