Home Addition Quote Checklist
A complete home addition quote should itemize every major trade — foundation, framing, roofing, electrical, plumbing, and HVAC — with a clear payment schedule tied to milestones. Missing line items on a six-figure project become very expensive change orders.
Required line items
A complete home addition quote should explicitly address each of the following. Items that are genuinely excluded should be stated as exclusions — not left unmentioned.
Foundation
Type, depth, and any soil preparation required
Framing
Exterior walls, roof structure, and connection to existing home
Roofing & exterior
Matching existing materials — specified by product
Windows & doors
Count, brand, and specs
Electrical
Service extension, outlets, lighting — scope itemized
Plumbing
If applicable — rough-in scope specified
HVAC extension
Ductwork extension or new equipment for the space
Insulation
Type and R-value specified
Drywall & interior finish
Including tape, texture, and paint
Flooring
Material specified, matching existing or new
Permits & inspections
All required permits and inspection fees
Architectural drawings
Whether included or client's responsibility
Common red flags in home addition quotes
These are the most frequently omitted or vague items. Any of them in your quote should prompt a follow-up before you sign.
No contingency amount
Additions frequently uncover unexpected structural conditions when opening walls. A quote with no contingency is either overconfident or setting you up for change orders.
Utility connections not itemized
Extending electrical, plumbing, and HVAC into the new space should each be a separate line item. Bundling them as 'utilities' obscures scope and cost.
No permit costs
Home additions require building permits, and often engineering review, setback verification, and multiple inspections. These costs can total $3,000–$10,000.
No payment schedule or schedule of values
For a project of this size, a payment schedule tied to completed milestones is essential. Lump-sum payment terms are a warning sign.
Architectural drawings not addressed
Most jurisdictions require stamped architectural plans for additions. If the quote doesn't address who produces drawings and at what cost, ask.
Three things to confirm before signing any contract
These apply regardless of project type and are the final checks before you commit.
Payment schedule tied to milestones
Never pay more than 30–40% upfront. Each subsequent payment should be tied to a defined milestone — completion of demo, rough-in, finish work, final walkthrough.
All permits identified and assigned
The quote should clearly state which permits are required and who is responsible for pulling them. Unpermitted work can affect your insurance and resale.
Warranty terms in writing
Get both manufacturer warranty details (on materials) and a contractor labor warranty (on the work itself). Verbal warranties are unenforceable.