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 a home addition contract
These are the final checks before you commit — specific to what matters most in a home addition project.
Draw schedule tied to inspected milestones — no exceptions
At this project scale, a milestone draw schedule is non-negotiable. Standard checkpoints: foundation pour and inspection, framing, rough-in (electrical, plumbing, HVAC) sign-off, drywall, and final. Never release a draw before the corresponding inspection passes.
Full permit list confirmed and assigned before work starts
Home additions require building permits, often including engineering review, setback verification, and multiple staged inspections. The permitting process can take weeks. Confirm who manages the permit application, how fees are paid, and that no work will start until permits are issued.
Structural warranty and exterior material warranties in writing
Confirm a labor warranty covering structural work for a minimum of 2 years, plus manufacturer warranties on windows, roofing, and exterior materials. 'Matching existing' is not a product specification — get specific brands and products written into the contract before you sign.