When planning a custom home, understanding the type of estimates you’re receiving is essential. Not all estimates are created equal, and if a builder doesn’t clarify which level they’re providing, it’s almost impossible to compare proposals or make confident decisions. At Corecraft, we use industry-standard estimate classifications to keep the budgeting process transparent from day one.
1. Class D Estimates – Early Feasibility & Budget Range
A Class D Estimate is your starting point. It’s created before detailed plans exist and is based on concept drawings, desired square footage, and comparable projects the builder has completed. The accuracy of this estimate will vary depending on the information available.
What a Class D Estimate Includes:
- High-level cost ranges (e.g., $500–$600 per sq ft)
- General allowances for finishes and systems
- Preliminary site considerations
- Initial soft cost projections
When to use it:
- Determining if your vision aligns with your target budget
- Deciding whether to proceed into architectural design
- Comparing conceptual options (1-storey vs 2-storey, suite vs no suite, etc.)
What information your Builder needs to prepare it:
- Concept Drawings (if available)
- Building site location
- Information on size, style, level of finish of home
- Information on unique requirements (accessibility, elevator, workshop, architectural details, etc.)
Timeline:
- 2 to 8 hours
- 1 week from initial meeting
What it doesn’t do:
A Class D estimate is not something you can build from or rely on for financing. It’s a directional guide, helpful, but broad. Its purpose is clarity at the earliest stage, not precision.
2. Class C Estimates – Preliminary Design & Detailed Budgeting
A Class C Estimate is where real budgeting begins. At this stage, architectural drawings are partially complete, major design decisions are drafted, and the builder has enough detail to create a line-item estimate. This Estimate should be accurate to +/- 20%.
What a Class C Estimate Includes:
- Detailed cost breakdowns (framing, windows, roofing, mechanical systems, millwork, etc.)
- Updated site costs based on surveys or geotechnical reports
- Allowances for finishes with ranges based on your design intent
- Preliminary quotes from key trades (framing, foundation, HVAC, electrical, etc.)
- A structured contingency recommendation
- A clear list of assumptions, inclusions, and exclusions
When to use it:
- Validating the financial feasibility before finalizing design
- Making informed decisions about layout, finishes, and features
- Preparing for construction financing
- Ensuring the design team and builder are aligned
What information your Builder needs to prepare it:
- Architectural drawings
- Site Survey
- Confirmation of Step Code
- Interior design information
- Preliminary discussions of mechanical, electrical, plumbing, automation systems, etc.
- Unique requirements such as: accessibility, elevator, workshop, architectural details, etc.)
- Information on site specific requirements such as: service upgrades, environmental, demolition, etc.
Timeline:
- 40 to 60 hours
- 6 to 8 weeks after receiving Architectural drawings
Why it matters:
The Class C stage saves clients the most money long-term. It’s where “scope creep” gets caught early and where decisions are made that shape 70–80% of your final cost.
3. Class B Estimates – Final Approved Budget
A Class B Estimate is the most accurate and is completed once full construction drawings and engineering are finalized. This is the budget your construction management agreement is based on. We typically prepare this Estimate after permit submission, but prior to construction starting. At this stage, there are minimal to no assumptions, nearly everything is defined. This Estimate should be accurate to +/- 10%.
What a Class B Estimate Includes:
- Accurate quotes from all major trades
- Accurate material takeoffs based on final plans
- Final appliance, plumbing, lighting, and finish selections
- Completed structural, mechanical, and architectural details
- Updated schedule and labour allocations
- A fully transparent cost-plus budget ready for contract
When to use it:
- To sign the construction agreement
- To finalize financing with your lender
- To set the baseline budget that will be tracked during construction
What information your Builder needs to prepare it:
- Permit Ready Architectural and Structural Plans
- Energy Modelling Report
- Site specific reports from consultants if applicable, such as: Arborist, Geotechnical, Septic, Fire Suppression, Environmental, etc.
- Confirmation of mechanical, electrical, plumbing, automation systems, etc.
- Complete Interior Design Drawings and specifications including: appliances, flooring, tile, lighting, plumbing, millwork, wall coverings, etc.
- Landscape requirements
- Confirmation of all unique and site specific requirements
Timeline:
- 30 to 50 additional hours after Class C Estimate
- 10-15 weeks after meeting to discuss Class C Estimate and receiving Interior Design Drawings and Specifications
Why it matters:
This estimate creates the foundation for a predictable building experience. When the builder has priced every component thoroughly, surprises are minimized and communication stays crystal clear. If there are significant changes to scopes of work, or scopes that have been added after the Class B Estimate, they will be entered as change orders during the construction process.
When planning a custom home, it’s important to understand that not all estimates are the same. Builders use different levels of estimates throughout the design process, each with its own purpose and level of accuracy. This structured approach, moving from a broad feasibility estimate (Class D), to a detailed preliminary estimate (Class C), and finally to a contract-ready estimate (Class B), is based on proven industry standards used across Canada and North America. These classifications ensure your budget becomes more accurate as your design becomes more detailed.
For homeowners, this clarity matters. Early estimates provide helpful cost ranges but aren’t meant for financing or final decision-making. As the design progresses and more information becomes available, your builder can produce a detailed Class C estimate that takes dozens of hours and includes real trade input. This is where risks, hidden costs, and scope creep are identified early, long before they can impact your final budget. By the time you reach a Class B estimate, every major component is priced properly, selections are accounted for, and the budget is reliable enough to support a construction contract.
At Corecraft, we follow this transparent estimating process because it protects our clients. It ensures the budget evolves responsibly, reflects real market conditions, and keeps everyone aligned – builder, homeowner, designers, and trades. By relying on industry-recognized standards and open-book pricing, we provide homeowners with the confidence they need to move forward knowing their project is planned with accuracy, clarity, and professional due diligence.
In addition to preparing estimates during the pre-construction process, we can also coordinate all required consultants and assemble the full package of documents needed for Building Permit submission. We also provide thoughtful value-engineering recommendations and design input to ensure your home meets your vision while staying aligned with your budget.
Our estimates use an open-book approach. Clients see exactly where every number comes from, including trade quotes and material pricing. Transparency builds trust, and trust builds better homes.