SDCI tree review (only if a regulated tree is in play)

When this applies

Seattle's Tree Protection Code (SMC 25.11) — see SDCI's Trees and Codes page — regulates the removal of "tier" trees on private property. For a second-story addition, three conditions trigger tree review:

1. A tier 1, tier 2, or "exceptional" tree falls within the construction impact zone (typically the drip line + 10 ft).
2. You need to remove a regulated tree to access the work.
3. The structural retrofit affects the foundation in a way that could damage tree roots.

If none of these apply — and for a vertical addition that doesn't change footprint, often none do — there's no tree review and you skip the step entirely.

What "regulated" means

The survey from step 1.1 should flag every tree above the regulatory threshold (currently 6" DBH for tier protection) and locate the drip lines. Cross-check the survey against the SDCI tree code page at the time you submit.

What's in the protection plan

• Tree inventory (from the survey).
• Construction-impact mapping.
• Protection fencing details and locations.
• Soil-protection measures within the drip line.
• Stamped by an ISA-certified arborist.

Cost

If an arborist report is required: $1,500–$3,500 for the report and protection plan. The arborist visit itself is usually a single half-day on site.