archive blog
Why a DADU Budget Needs a Contingency
A DADU contingency budget holds money for necessary work nobody can price at signing. Topics include the difference from allowances, Seattle side sewer ownership and repair permit fees, tree protection, SDCI hourly and reinspection fees, special inspections, permit revisions, sizing the reserve, approving and tracking draws and lien precautions.
Which Interior Selections Have the Biggest Budget Impact
DADU finish allowances hold the price range for interior items that are still unpicked when a contract is signed. This covers which selections carry allowances, what each line should spell out, Washington contract guidance, change orders, Seattle energy code lighting rules, appliance and water heater credits, fixture flow limits and when to lock in choices.
How Building Shape Influences DADU Construction Pricing
Two Seattle backyard cottages of the same size can cost very different amounts to build. This covers how footprint shape, roof form, stories, glass and ceilings drive DADU design cost, plus lot coverage, stormwater triggers, permit valuation and pre-approved plan limits, with an invented comparison and questions to settle before drawings.
What Utility Connections Add to a DADU Budget
A Seattle backyard cottage can trigger published utility charges on top of trenching. This covers who bills what, when a DADU needs a larger water service, 2026 SPU installation and system development charges, side sewer permits, the King County capacity charge at the ADU rate, drainage charges, City Light service steps, lead times and an invented example.
How Site Work Changes Backyard Cottage Costs
Site work for a Seattle backyard cottage grows with the city thresholds the ground triggers. This covers grading limits, walls near property lines, the pre-application site visit, stormwater review at 750 square feet, tree protection areas, critical areas and the dry season, utility locates and old heating oil tanks, with an invented example.
What a DADU Construction Estimate Should Include
A backyard cottage estimate is a list of scope decisions, and two similar totals can describe very different projects. This walks through design, permits and county charges, site staging, building systems, utilities, allowances, general conditions, sales tax, contingency and exclusions, with questions to ask every bidder.
Why Seattle DADU Budgets Vary From One Property to Another
The same backyard cottage plan can carry very different budgets on two Seattle lots. This walks through slope and access, utility runs and King County charges, standards that do not apply to ADUs, design shape, pre-approved plans, labor and finish allowances, with a checklist before asking for estimates.
How Mercer Island Lot Conditions Shape ADU Planning
Mercer Island runs on interim ADU rules with a shared floor area budget, parking tied to lot size and a wet season limit on steep lots. Check the land first.
What Renton Homeowners Should Check Before a DADU
Renton allows two ADUs per lot and offers free pre-approved model plans. Its size cap, parking rule and site permits still differ from Seattle’s.
How Shoreline Rules Affect Accessory Dwelling Unit Options
The City of Shoreline sets its own ADU code, separate from Seattle and from shoreline environmental rules. Two units, sprinklers and no stock plans stand out.