ADU Construction Planning in Redmond, WA

Redmond’s public material is useful, but dates matter. Older guidance describes one ADU, size and occupancy provisions that may have changed as the City implemented Washington HB 1337. A provider summary or archived PDF should not decide the 2026 project.

This independent page is not the City of Redmond or a contractor. Confirm the live code, permits and property with City staff.

What does Redmond’s permit page say?

The City’s Residential Permits page lists adding an ADU among work that needs a building permit. It separately lists garage conversion to living space. That distinction is useful when comparing a detached build, attached addition and conversion.

The permit page also links to Redmond’s zoning code. Use the current code rather than relying only on an explanatory handout.

Why should older Redmond ADU guidance be treated carefully?

An older City ADU guide says units are allowed in residential zones and are commonly limited to 1,500 square feet. Older code material also describes one ADU and prior occupancy or ownership provisions. Redmond worked on code changes in 2025 to address state housing laws.

Before selecting a plan, ask the City to confirm:

• number and combination of ADUs allowed;
• current maximum size and height;
• setbacks, coverage and placement;
• parking or occupancy provisions;
• conversion and detached requirements; and
• effective ordinance and code section.

Save the link and checked date in the project brief.

What belongs in a Redmond lot screen?

Collect the parcel, zoning, existing building and survey or site-plan facts. Then review:

• proposed unit type and footprint;
• yards, height and lot coverage;
• trees and critical areas;
• slope, drainage and retaining conditions;
• access for excavation and construction;
• sewer, water and electrical service;
• existing garage or basement condition; and
• easements and private restrictions.

Redmond includes urban neighborhoods and properties close to streams, slopes or wooded areas. Site constraints can control foundation and placement even when the zoning use is allowed.

Use the ADU feasibility guide to prepare the evidence before paying for a full plan.

How should a garage conversion be evaluated?

Because Redmond specifically lists garage conversion to living space, owners may assume it is a small remodel. Check the slab, moisture, insulation, ceiling height, fire separation, emergency escape, structure, electrical capacity and drain path. Converting a garage to an independent dwelling adds kitchen, bathroom, heating and life-safety work.

Compare the complete conversion with an attached addition or detached ADU. Preserving storage and parking may change the household decision.

Which design and permit responsibilities need names?

The proposal should identify who prepares existing-condition drawings, site plan, architecture, structural work, energy documents and trade plans. It should also name the party responding to City corrections and coordinating utility or right-of-way work.

The design and permits guide provides a responsibility schedule. Do not let “we handle permits” replace a list of documents, fees and exclusions.

What utility and site work belongs in the quote?

Map electrical equipment, water, sewer and stormwater before comparing construction totals. Ask whether services can be shared, whether capacity upgrades are expected and who restores paving and landscaping after trenching.

Tree protection, erosion control, tight access or a long connection can change both cost and schedule. The utilities and site-work guide lists the items that should not disappear inside a base price.

How much does a Redmond ADU cost?

The geo study found low but stable search demand; it did not establish a construction price. Use the Seattle-area ADU cost guide to create a full budget, then replace broad ranges with the property’s design and site work.

Compare feasibility, survey, design, engineering, permits, access, foundation, building work, utilities, finishes, restoration and contingency. Ask providers to state what is owner-supplied and what would trigger a change order.

How should Redmond providers be compared?

Verify the legal entity and registration in Washington L&I. Request recent Redmond or similar Eastside ADU projects, permit references where appropriate and clients who can discuss scope control. Ask who performed design and who completed construction.

Give each provider the same lot facts, plan basis and allowance schedule. Use the builder comparison to review project evidence, permits, utilities, payment, schedule assumptions and written warranty terms.

Create a current-code question list

Where an older Redmond guide and the current website do not clearly align, send the City a project-specific list rather than guessing. Identify the parcel, existing dwelling, proposed attached, detached or conversion path, intended floor area and any existing accessory unit. Ask which adopted code and submittal checklist control in 2026.

Record answers about height, setbacks, size, unit count, parking, tree or critical-area review and any owner-occupancy or recording requirement. Save the response date and staff contact with the project file. This protects the design team from silently using a pre-update summary.

What should a Redmond bid package contain?

Provide the same site plan or survey, existing-condition information, concept, finish schedule and utility assumptions to each provider. Require separate lines for design and engineering, City corrections, permits, demolition, foundation, building systems, utility work, drainage and restoration.

Ask bidders to identify unknowns that require field or agency investigation. Compare those investigation tasks and allowances before comparing the totals; an apparently lower number may simply leave more Redmond-specific work unresolved.

Include the permit portal link and the City’s written response in the bidder packet so every team prices the same current path.