Solicit bids from 3-5 Seattle older-home addition GCs

Before you read any bids: the empirical reality

Industry surveys are consistent: more than one in three homeowners (37% per Houzz's 2025 U.S. Renovation Trends Study) end up spending more than they planned, versus 35% who finish on budget and just 3% under. Older houses hide more unknowns than new-build, finish-stage upgrades compound late, and corrections from the inspector add line items nobody priced into the bid.

Practical implication: budget the lump-sum bid + 10–20% contingency, separately. Don't fold the contingency into your project envelope and then "use it up" buying finish upgrades — that's how the contingency disappears and the real overrun arrives. Treat it as an untouched reserve for genuine unknowns (failed soils test, dry rot found at framing, code-correction work).

Before you write the RFP: are you carving out any trades?

If you're thinking about hiring one or two trades directly (appliances, finish hardware, post-CofO landscape) instead of running everything through the GC, read Splitting scope between your GC and trades you hire directly before you finalize the bid package. On a second-story addition the workable carve-outs are narrow — but the expansion explains why, and what the alternatives look like.

Where to find good GCs

You're looking for builders who've finished a second-story addition (not just a kitchen remodel, not just a DADU) on a Seattle older house in the last few years. There are three good places to look:

1. Recent permit history. The SDCI Permit and Site History Research Tool lets you search permits by type and neighborhood. Filter for "addition" permits in the last 3 years; the contractor names that show up over and over are your local specialists. This is the single best list.
2. Your designer's short list. Your designer has worked with several GCs on Seattle additions and knows who's good to work with. Ask. It'll be a short list, biased toward GCs who collaborate well — which is what you want.
3. GCs who publish their work. Hammer & Hand, CRD Design Build, Model Remodel, and a few others post detailed project diaries. You can read how they think before you call them.

Aim for three to five bids. Three gives you a real comparison. Five gives you negotiating room.

Send everyone the same package

Every GC has to be bidding the same thing. Otherwise you're not comparing prices — you're comparing different additions.

The "same thing" means:

• The same permit-ready plan set (same sheets, same revision, same date).
• The same abatement scope (lead and asbestos report from step 0.4 attached, with abatement called out as a separate line).
• The same foundation strategy (retrofit-in-place or lift, with the engineer's recommendation attached).
• The same allowance lines for finishes, cabinets, fixtures, appliances — with the same dollar amounts called out.
• The same exclusions stated up front (e.g., "no landscape," "no detached garage work," "no driveway").

Reading the bids when they come back

When three to five GCs price the same package, the bids will usually cluster within 10–15% of each other. That's a healthy spread.

If one bid comes in 25%+ below the rest, walk it line-by-line against the median. Almost always the gap is missing scope (a foundation read that assumes simpler retrofit, abatement left out, an allowance dropped) — not a more efficient builder. Add the missing scope back and re-compare.

What it actually costs in 2025–2026

The honest range right now for a Seattle second-story addition:

• Envelope-only addition (~600–900 sq ft new space, retrofit foundation, minimal first-floor work): $300,000–$500,000.
• Typical scope (800–1,200 sq ft new, modest first-floor reconfiguration, MEP throughout, knob-and-tube remediation): $400,000–$650,000.
• Lift + addition (Option B from step 2.2, new foundation): $550,000–$750,000.
• Lift + new ground floor + addition (Option C, three-story end state): $700,000–$1M+.

You'll see "$200K addition" headlines from before COVID. Don't budget against them.