Sandy staff, consultants preview code updates to ease prefabricated and mass-timber housing

City staff and consultants presented recommended zoning and code edits intended to make it easier to use prefabricated construction — including but not limited to mass timber — during a joint Sandy City Council and Planning Commission work session.

The presentation, led by consultant Brandon Crawford of MIG and followed by comments from Kelly Reed, regional representative for the Oregon Department of Land Conservation and Development (DLCD), reviewed a grant-funded audit of Sandy’s rules, changes required by state law and optional code changes the city could adopt to encourage prefabricated and modular dwellings.

Those required changes are driven by House Bill 4064 and related state rules, consultant Brandon Crawford said. “The state statute requires all cities throughout the state to allow prefabricated homes or manufactured homes on any lot that allows single-family dwellings,” he told the council and commission. The consultant’s draft edits focus first on definitions and on ensuring the city treats modern manufactured homes the same as single-family houses where state law requires it.

Why this matters: the project is funded by a DLCD technical-assistance grant supported by an Economic Development Administration award to the state. The grant pays for the consultant work; the city has no local match requirement, staff emphasized. The changes would affect how the city regulates manufactured homes, prefabricated modular housing and where those units may be sited — decisions that can affect housing options and permitting requirements for property owners.

Key details and options

- State-required clean-up. MIG’s recommendations include updating the city’s definition of “manufactured home” so that only modern manufactured homes (post‑1976) are treated the same as single‑family dwellings on single lots while older residential trailers and mobile homes remain regulated differently and generally are only allowed in manufactured‑dwelling parks. The consultant said that most of the city’s earlier code work already put Sandy close to compliance and the recommended edits are minor clarifications.

- Broader “prefab” approach. MIG used prefabricated and modular housing as umbrella terms that encompass mass timber panels and other off‑site construction methods. Brandon Crawford said the recommended changes are intended to reduce unintended barriers to off‑site construction generally, not only to promote mass timber.

- ADUs. The consultant recommended giving property owners more flexibility for accessory dwelling unit (ADU) size (examples given were raising the cap to about 800–900 square feet or a percentage of the primary dwelling, whichever is smaller), and making ADUs exempt from certain public facility improvements. Council members were split: several said a modest increase could aid multigenerational households and offer affordable options, while others warned that very large ADUs could effectively become second primary residences and raised concerns about sewer ERU limits and parking. Staff noted current state rules limit cities’ ability to require additional parking for ADUs and that system development charge (SDC) treatment remains allowable under current law.

- Cottage clusters. MIG proposed optional standards for cottage clusters — multiple detached small units grouped around shared open space — and described them as typically located on one lot with shared maintenance obligations. The consultant said the state’s model code was used as a starting point but that Sandy, as a smaller jurisdiction, has discretion over how to adopt such standards. Council and commissioners raised concerns about cost effectiveness, ownership models, common‑area management, and whether the city should prioritize higher‑density multifamily housing that yields more units per ERU and per acre.

- Next steps and timing. Staff said the state grant requires a pre‑March work session and that the consultant will finalize recommended edits if the city wishes. Planning staff recommended adopting only the mandatory statute‑consistency edits promptly and considering optional measures such as ADU size limits and cottage‑cluster rules as part of Sandy’s upcoming Housing Production Strategy (HPS), where they could also earn the city credit toward housing‑production targets.

What officials and DLCD said

Kelly Reed, DLCD regional representative, described mass timber and the linked industry work as “an emerging industry” and said the state and federal grants backing the technical assistance include support for manufacturing facilities (she referenced state materials noting projects such as a Portland facility that is expected to supply mass‑timber panels for modular homes). “There’s hope,” Reed said, “and there’s a lot of effort behind making that happen.”

Mayor Walker asked for clarification of “mass timber” versus modular or SIP/SYP panel construction, saying she was “confused about the use of the word mass timber” and worried the label might be misleading for local economic‑development aims. Crawford and staff agreed that the project’s “mass timber” branding reflected the grant’s focus but that code changes address prefabrication broadly, including other panelized systems.

Commissioners and councilors also pressed staff on practical details: whether ADU increases would worsen sewer capacity constraints (staff said ADUs require ERUs and that sewer allocation remains a council policy issue), whether cottage clusters tend to be rental or condominium ownership models (Cottage clusters often end up condominiumized with an HOA, consultants said), and whether the city should delay nonmandatory changes until the HPS work to preserve credit toward the production plan.

Bottom line and staff recommendation

Staff urged the council to approve the draft statutory‑consistency edits and to treat optional items — revised ADU sizing and new cottage‑cluster standards — as candidates for detailed consideration in the Housing Production Strategy. City staff said the state grant covered the consultant work and that the city would not be required to adopt any of the consultant’s optional recommendations.

The work session produced no vote to adopt code amendments; the city instead directed staff to carry the mandatory HB 4064/ORS‑consistency changes forward and to include the optional topics in the HPS process if the council wishes to pursue them later.