# 605 Fifteenth Street — design & feasibility notes

Prepared September 4, 2026. Concept study for 605 15th Street SE, Cedar Rapids, Iowa, parcel 14223-09001-00000.

## Selected development path

Proceed with one principal residence and one detached garage apartment. The current City GIS identifies T-R1, Traditional Residential Single Unit. The February 28, 2026 zoning ordinance's Table 32.02-19 limits T-R1 to one unit per parcel and per structure, with ADUs expressly excluded. Two separate principal residences are therefore not the as-of-right scheme supported by this table; a different entitlement approach would require City review.

Section 32.03.04.C.1 recognizes detached ADUs, including garage apartments. Its maximum gross floor area is 1,000 sf or 50% of the primary residence's gross floor area, whichever is greater. It permits one detached ADU plus one attached/internal ADU; this study proposes only one detached ADU. The proposed 480 sf upper-floor apartment is below the stated limit.

T-R1's table lists 15 ft front, 10 ft street-side and 10 ft rear setbacks, internal sides as “3/8,” 35 ft maximum height, and 80% maximum coverage. T-R1 directs driveway access to an alley or side street where available. These are screening criteria, not a finding that the illustrated design complies.

Source: [City zoning ordinance, effective February 28, 2026](https://www.cedar-rapids.org/Community%20Development/Zoning/Chapter%2032%20-%20Zoning%20Ordinance_2.28.2026_2ndEd_1%20page_High%20Res.pdf?t=20260408123156919), printed pp. 22–23 and 103.

## Parcel findings

The City parcel service returns address 605 15TH ST SE, parcel 142230900100000, stated area 0.095 acres, and legal-description text “WELLINGTON PLACE 7TH N 75' STR/LB 1 14.” The mapped polygon's edge lengths are approximately 56.38, 75.68, 52.79 and 75.56 ft. This is a tapered parcel. The approximate 75 × 55 ft rectangle used for design exploration is not a boundary survey.

The zoning layer returned T-R1 at the parcel center. The zoning-overlay query returned no intersecting feature at that point. This does not rule out a historic designation, flood regulation, easement or other restriction maintained in a different dataset.

Sources: [City parcel service](https://crgis.cedar-rapids.org/arcgis/rest/services/Maps/TaxParcelQuery/MapServer/0), [City zoning service](https://crgis.cedar-rapids.org/arcgis/rest/services/Maps/Zoning/MapServer/3), [City zoning overlay service](https://crgis.cedar-rapids.org/arcgis/rest/services/Maps/Zoning/MapServer/6). Query snapshots are included in `research-evidence.json`.

## State law

Iowa Code §364.3(23) establishes a state ADU framework, including the 1,000 sf / 50% size rule and limits on additional parking requirements specific to an ADU. Building regulations and applicable restrictions still matter. SF 2369, effective July 1, 2026 per the Legislature's bill listing, further clarifies allowed principal-use districts, size calculations and historic-area review. Do not rely on the City's older 2019 or 2024 ADU PDFs for current requirements.

Sources: [Iowa Code §364.3](https://www.legis.iowa.gov/docs/code/364.3.pdf), [SF 2369 enrolled text](https://www.legis.iowa.gov/docs/publications/LGE/91/SF2369.pdf), [Legislature bill listing](https://www.legis.iowa.gov/legislation/findLegislation/passedEither).

## Design program

- Main home: 24 × 28 ft gross footprint, two levels, approximately 1,344 sf gross. Ground floor living/dining/kitchen and powder room; three upper bedroom zones and full bath.
- Garage building: 20 × 24 ft gross footprint, garage and independent stair below; approximately 480 sf gross studio apartment above. Stair and wall areas reduce the net usable living space.
- Courtyard: pedestrian connection between households, restrained planting and warm path lighting.
- Materials: ivory and sage siding, charcoal gables, pale trim, oak-toned doors. Interactive variants include slate blue.

These room arrangements are spatial studies. Door openings, partitions, stair geometry, headroom, egress, fire separation, structural systems, energy performance and mechanical routing have not been resolved into construction drawings. Garage door geometry is representational. The roof does not animate as a building assembly; floor controls hide model groups to expose the concept.

## Items to resolve before design approval

1. Obtain a boundary/topographic survey; confirm actual street rights-of-way, legal front/street-side/rear line designations and existing tree locations.
2. Have City Development Services confirm setbacks and their interpretation, including the table's internal-side notation, porch projection, eaves, driveway/corner sight triangle and any design-review standards.
3. Refit the footprint to the tapered parcel. In the current rectangular diagram, the porch extends ahead of the 15 ft principal front setback; this is an unresolved encroachment question. No dimensional compliance is claimed.
4. Check historic status, floodplain, title/easements, water/sewer services, drainage, parking access and fire separation. The small existing structures seen in neighboring yards are not presumed to belong to this lot; the proposed garage is new construction.
5. Develop an architect-reviewed floor plan and engineered building documents before budgeting or permitting as a final design.

No City contact, application, permit or approval was obtained as part of this work.

## Using the deliverables

Open `605-interactive.html` in a modern browser. Keep its `assets` folder beside it. It includes the original-photo reveal, orbit/zoom model, ground and upper views, room camera presets, day/evening lighting, finish variants and screenshot export. The 3D library is included locally, so the experience works offline; source-document links require internet access.

`605-home-and-adu.blend` is the editable Blender 5.2 scene with named collections. `605-home-and-adu.glb` exports the concept geometry and materials for downstream 3D workflows, including an Unreal import workflow if desired. No native Unreal project or photogrammetric reconstruction was created.

The photo rendering was generated with the built-in image-generation tool using the original site photo. It aims to retain the neighborhood, with new work naturally occluding existing buildings, but it is not a pixel-registered or survey-accurate composite. The original photo is included unchanged. The 3D model is a separate schematic design, and its positions and appearance are not an exact match to the AI image. The neighboring houses are not reconstructed or altered in the 3D scene; they remain available in the original photo views.