ADU Guides

How to compare multiple ADU contractor bids

Three contractors can look at the exact same ADU project and come back with three bids that are $60,000 apart. That gap usually isn't one contractor overcharging — it's that the bids aren't actually comparable yet. Here's how to make them comparable.

United Build Partners Updated 2026 8 min read

Why bids for the same project can look so different

A bid is only as good as the scope it's based on. If one contractor is pricing a mid-grade finish package and another is pricing builder-grade materials, of course their numbers won't match — even though both bids might be perfectly fair for what they actually include. Before you compare price at all, you need to compare scope: what's included, what's excluded, and what assumptions each contractor made.

Line up scope before you compare price

Does the bid include design and engineering, or is that billed separately? Some bids bundle it in; others treat it as a pass-through cost.
Does it include permit and impact fees, or are those listed as an allowance/estimate you'll pay directly? See our cost guide for what's typically included in a per-square-foot number versus what's often separate.
What's the finish level assumed? Ask each contractor to specify flooring, countertop, and fixture allowances in dollar terms, not just brand names — "granite countertops" can mean a $40/sqft slab or a $150/sqft one.
Does it include site work — grading, drainage, utility trenching, driveway modifications — or is that a separate line item or excluded entirely?
What's the payment/draw schedule, and does it match how the work is actually sequenced? A schedule that front-loads payment before major milestones is worth asking about.

Once you've confirmed all three contractors are pricing the same actual scope, the price comparison becomes far more meaningful — and often the gap between bids shrinks considerably once apples are actually being compared to apples.

Questions to ask every contractor, side by side

Questions to ask ADU contractors when comparing bids
QuestionWhy It Matters
How many ADU projects have you completed?ADU-specific experience differs from general remodeling experience — permitting and inspections have their own quirks.
Can I see your current license and insurance?Confirms they're legally authorized to do the work and covered if something goes wrong.
What's your typical timeline for a project like mine?Compare against realistic ranges in our construction timeline guide — a bid that's dramatically faster than others deserves a follow-up question.
How do you handle change orders?Clarifies what happens (and what it costs) if something needs to change mid-project.
Can you provide references from recent ADU clients?Past clients can tell you things a bid document can't — communication style, how surprises were handled, whether the timeline held.
What warranty do you offer on the work?Confirms what recourse you have if something fails after completion.

The lowest bid isn't automatically the best bid

A bid that's meaningfully lower than the others is worth a direct conversation about why — sometimes it reflects genuine efficiency, and sometimes it reflects a thinner scope, lower-grade materials, or an unrealistic schedule that leads to change orders later. The goal isn't to find the cheapest number; it's to find the bid that most accurately and completely reflects the project you actually want built.

Common exclusions to check every bid for

Do this interactively

Our free ADU bid comparator lays your bids side by side, computes true cost per square foot, and flags exactly which of the scope items below each bid leaves out — nothing saved or sent.

The most expensive differences between bids are usually the items a bid quietly leaves out. Before comparing totals, confirm — in writing — whether each proposal includes:

A full map of the non-construction budget lines lives in our ADU soft-costs guide — worth reading alongside any bid.

Red flags worth taking seriously

How United Build Partners fits into this process

A free property review doesn't replace the work of comparing bids yourself, but it does mean the contractors you're comparing are ones we've connected you with based on your specific project type and location — not a cold list you're sourcing on your own. You still compare their proposals and make the final call; we just aim to make sure everyone at the table is actually suited to what you're building.

Frequently asked questions

Three is a common, practical number — enough to see a real range of pricing and approach without making the comparison process unmanageable. United Build Partners typically introduces homeowners to up to three contractors suited to their project for this reason.

Not automatically. Confirm the bids all reflect the same scope, finish level, and included items first — a lower number sometimes reflects a thinner scope rather than better value.

Yes, especially before scope is aligned. Different contractors make different assumptions about finish level, what's included versus billed separately, and site conditions — which is exactly why comparing scope before price matters.

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