Contractor Quote Checklist
Home Addition Quote Checklist Before Signing
Short answer: a home addition quote should define the plans, design responsibility, permits, foundation, framing, roof tie-in, exterior envelope, HVAC, electrical, plumbing, insulation, lead-safe work if relevant, utility locating, finish allowances, site access, cleanup, warranty, and written change-order process before construction starts.
A home addition can start as a simple need: a bedroom for a growing family, a first-floor suite, a home office, a larger kitchen, or a mudroom that finally handles daily life. The quote, however, is not simple.
An addition touches the existing house. It may change the roof, foundation, drainage, heating and cooling, electrical load, windows, insulation, siding, and permit path. Use this checklist to make sure the quote describes the whole project, not just the new square footage.
Start With Plans And Responsibility
Ask what the quote is based on: conceptual sketch, measured drawings, permit-ready plans, engineer review, design-build proposal, or a rough budget. A quote based on incomplete plans should say what is still unknown.
Also ask who is responsible for design decisions, structural calculations, revisions, and permit comments. If the contractor is not providing architectural or engineering services, the quote should state that clearly.
Permits And Inspections Are Core Scope
FEMA’s homeowner building code materials emphasize that codes and local enforcement matter for construction. For an addition, ask who applies for permits, which inspections are expected, and whether the quote includes responding to inspector comments.
The quote should identify building, electrical, mechanical, plumbing, zoning, septic, floodplain, or right-of-way issues if they may apply. Local requirements vary, so the contractor should not treat permits as an afterthought.
| Quote area | Question to ask | Why it matters |
|---|---|---|
| Plans | Are these permit-ready drawings or budget-level sketches? | Incomplete drawings can hide structural, finish, and utility changes. |
| Foundation | What foundation type, excavation, drainage, and soil assumptions are included? | Unknown soil, depth, or water conditions can trigger major changes. |
| Roof tie-in | How will the new roof connect to the existing roof and drainage path? | Leaks and ice or water problems often start at bad transitions. |
| HVAC | Will the existing system serve the addition, or is new equipment or zoning needed? | Comfort problems can remain after construction if load and airflow are not checked. |
| Allowances | Which finishes are fixed, and which are placeholders? | Windows, flooring, trim, doors, lighting, and fixtures can shift the scope. |
Foundation Scope Should Be Specific
The quote should describe excavation, footing, slab, crawlspace, basement connection, frost depth assumptions, drainage, waterproofing, backfill, and haul-off. If the contractor has not confirmed soil, depth, or existing foundation conditions, ask how discoveries will be handled.
If digging is required, ask who contacts 811 and waits for utility responses before excavation. The foundation plan should not proceed as if gas, electric, water, sewer, irrigation, or communications lines do not exist.
Framing And Structural Tie-Ins Need Detail
An addition connects new loads to an existing structure. Ask whether the quote includes beams, posts, wall removal, floor leveling, headers, shear walls, connectors, engineer letters, and temporary support if openings are made.
Do not assume “framing included” covers structural surprises. The quote should state what is known, what is assumed, and what would become a change order.
Roof, Siding, And Water Management Are One System
The new roof must tie into the old roof. The new siding must meet the existing exterior. Gutters, flashing, valleys, step flashing, housewrap, trim, windows, doors, grading, and drainage all affect whether the addition stays dry.
Ask whether the quote includes matching existing roofing and siding or only installing new materials on the addition. Also ask how visible mismatch, discontinued products, and transition details will be approved.
HVAC Capacity Should Not Be Assumed
A larger house may need more heating and cooling capacity, different duct routing, added returns, zoning, mini-split equipment, ventilation changes, or insulation upgrades. Ask whether the contractor has evaluated the load and airflow, or whether HVAC is excluded.
DOE explains that insulation levels depend on climate, system type, and the part of the house being insulated. A quote should specify insulation and air sealing, not just drywall and finishes.
Electrical And Plumbing Should Be Mapped
Ask whether the quote includes new circuits, lighting, outlets, smoke or carbon monoxide alarms where required, panel capacity review, low-voltage wiring, exterior lighting, and inspection. If the addition includes a bathroom, laundry, kitchenette, or wet bar, ask how plumbing, drains, vents, water lines, and shutoffs are included.
Panel upgrades, trenching, service changes, drain rerouting, and fixture choices should not appear late without a written path for approval.
Older Homes May Need Lead-Safe Work
If the existing house was built before 1978 and painted surfaces will be disturbed, ask whether EPA Renovation, Repair and Painting requirements apply. Additions often involve cutting exterior siding, removing trim, opening walls, replacing windows, or tying new rooms into painted surfaces.
The quote should identify lead-safe containment, cleanup, documentation, and certified firm responsibility when applicable.
Finish Allowances Need Boundaries
Home addition quotes often use allowances for windows, doors, flooring, trim, paint, cabinets, fixtures, tile, lighting, and hardware. Ask whether each allowance includes product, labor, delivery, tax, markup, and disposal.
Also ask selection deadlines. A late window, door, floor, or fixture can delay insulation, drywall, inspection, and final completion.
Site Access And Daily Living Conditions Matter
Ask how the crew will access the work area, where materials will be stored, whether temporary walls or dust barriers are included, how weather protection works, and which parts of the house will be unavailable during construction.
If the family will live in the home during the project, ask about work hours, temporary kitchen or bathroom access, pets, children, parking, debris, restroom use, and daily cleanup expectations.
Change Orders Should Name Common Unknowns
Unknowns are common in additions. The contract should say what happens if the crew finds rot, bad framing, undersized electrical service, hidden plumbing, foundation cracks, termites, asbestos-suspect material, lead paint, drainage issues, or plan changes required by the inspector.
The FTC advises homeowners to be careful with contractors and written agreements. For an addition, written change orders are not paperwork clutter. They are how the homeowner avoids making expensive decisions under pressure.
Before You Sign, Ask These Questions
- Are the drawings permit-ready, and who handles revisions?
- Which permits and inspections are included?
- What foundation, excavation, drainage, and soil assumptions are in the quote?
- Who contacts 811 before digging?
- How will the new roof, siding, flashing, and gutters tie into the existing house?
- Has HVAC load, ductwork, and return air been addressed?
- Does the electrical scope include panel capacity review and new circuits?
- Are insulation, air sealing, vapor control, and ventilation specified?
- Which finishes are allowances, and how are overages approved?
- What hidden conditions become change orders?
FAQ
Can I compare home addition quotes by square footage?
Only as a rough starting point. Two additions with the same footprint can have very different foundation, roof, HVAC, plumbing, electrical, finish, and permit requirements.
Should the quote include design or engineering?
It should say whether design and engineering are included or excluded. If the quote is based on incomplete drawings, ask what decisions remain before a firm construction contract is possible.
What is the biggest hidden risk in a home addition quote?
The biggest risk is assuming the existing house can accept the addition without changes. Roof tie-ins, structure, HVAC, electrical service, drainage, and code requirements often drive the real scope.
Should I live in the house during the addition?
Sometimes, but the quote should explain dust control, temporary barriers, work hours, utility shutoffs, weather protection, access, and cleanup. Living through construction is easier when those expectations are written.