Thornton staff seeks direction on subdivision standards, sidewalks, and nonconformities in code rewrite

City planning staff and the development‑code consultant presented proposed changes to Article 10 (subdivision standards) and Article 12 (nonconformities) of Thornton’s development code and sought council direction on several substantive items, including sidewalks, green courts, motor courts and rebuild allowances for nonconforming buildings.

Karen Radomski, the city’s long‑range planning manager, introduced the matter and said changes reflect code reorganization and relocation of technical standards (transportation moved to Article 9; grading moved to Article 6; water/sewer standards and decision procedures moved to other parts of the code) so subdivision standards are slimmer and clearer. Consultant Jackie Berg summarized proposed Article 10 content covering lot/tract definitions, public land dedication and easement requirements, new standards for green courts and motor courts, and assurances of completion.

A major policy item discussed was whether detached sidewalks should be required on all new public and private local streets. Staff said the current code requires detached sidewalks on collectors and arterials but leaves them optional on local streets; the proposed rewrite would require detached sidewalks on all streets. Home‑builder stakeholders told staff this raises two concerns: increased long‑term maintenance costs (landscape strip upkeep often falls to HOAs/metro districts or homeowners) and potential stormwater/drainage infrastructure increases. Staff noted a 2024 update to the Mile High Flood District design manual treats xeriscaping the same as traditional landscaping, reducing a drainage‑related objection. The home‑builders’ alternative proposal would require detached sidewalks only in targeted locations (leading to parks or schools).

Council members generally supported the targeted approach. Several members said they opposed requiring detached sidewalks throughout local neighborhoods because the ongoing maintenance cost is passed to homeowners or the city, and they favored requiring detached sidewalks in areas that lead to parks and schools to improve safety for children and pedestrians. Staff clarified the requirement would apply only to future development and noted that many new parks are owned and maintained by metro districts rather than the city, so maintenance responsibilities typically fall to those districts and ultimately to their taxes/assessments.

On configuration standards, staff proposed formalizing green court and motor court development types (previously handled via planned‑unit developments) with by‑right standards. Proposed green‑court rules would allow clusters of small units with limits on court length and size of common areas. Motor courts would be allowed for detached units and duplexes with off‑street parking located outside the shared accessway; staff proposed limiting motor courts to 25% of a subdivision and up to six dwellings per motor court (home‑builders suggested eight with added guest parking). Council signaled support for the standards and for allowing up to eight units if guest parking is provided and fire‑department access requirements are met.

On nonconformities (Article 12), staff proposed limited changes to clarify language, permit development of nonconforming lots that can meet all other code standards, prohibit increasing the degree of nonconformity through subdivision consolidations that create leftover strips, and change the rebuild threshold for nonconforming buildings from “50% of structural replacement cost” to “pre‑damage assessed value” to simplify administration. Staff also proposed that accessory buildings that are associated with a primary building be removed if the primary building is demolished during major redevelopment.

Council provided direction to staff to pursue the targeted sidewalk approach (prioritize sidewalks leading to parks and schools rather than a blanket requirement) and to advance the green court and motor court standards (with consideration for up to eight motor‑court units with guest parking and subject to fire code). Staff will bring draft ordinance language and the remaining articles back through planning commission and public hearing steps as part of the broader development‑code update timeline.