Structural engineers send proposals before any design or inspection begins, often after a brief call or a first look at the plans or site. Clients, especially homeowners and contractors, usually compare two or three quotes and look at price, turnaround time, and what is included. A clear scope in the proposal is also how you protect yourself from open-ended work.
When to use estimates: Use estimates to provide project quotes and get client approval before starting work. Once approved, convert your estimate to an invoice with one click to collect payment.
Create an invoice for payment collection
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Invoice_1001_Client_2026-10-14.pdf
Clients often assume a stamped letter includes full drawings, or the reverse. Naming each deliverable avoids that mismatch.
Travel and field time are real costs. State how many visits are in the fee and the hourly rate for extra ones.
Listing the applicable building code edition and the permitting authority shows what standard you are designing to.
Architectural plans, survey, soils report, and existing drawings drive your schedule. Delays on the client's side should not become free work for you.
Plans change as owners and architects make decisions. A fixed number of rounds keeps the fee tied to the scope.
Clients often expect structural engineers to cover related items. Naming exclusions makes it clear what is not included.
Material and labor costs for the client may change, and your workload will too. A proposal expiration date and a stated retainer set expectations.
| Service | Priced | Typical range |
|---|---|---|
| Principal or PE engineering time | per hour | $150-250 |
| Project engineer / EIT time | per hour | $90-150 |
| CAD drafting or modeling | per hour | $65-110 |
| Single beam or header calculation with stamped letter | flat fee | $400-1,200 |
| Residential site inspection and report | flat fee | $500-1,500 |
| Foundation or retaining wall design with stamped drawings | flat fee | $1,500-5,000 |
| Residential addition or remodel structural design | flat fee | $2,500-8,000 |
| Expert witness or forensic review | per hour | $200-350 |
Typical US ranges. Rates vary by region, experience, and job size.
Wood-frame additions are routine, but work on older masonry, unknown framing, or damaged structures involves more risk and more field time. Add to the fee when conditions are unknown, or bill existing-condition investigation hourly.
Separate schematic design, construction documents, and construction administration into distinct line items. Clients can see what they are paying for and you can bill as each phase completes.
For investigations, an estimate of hours with a cap that requires client approval to exceed gives the client confidence without committing you to a fixed fee on uncertain scope.
For uncertain projects, offer a paid site visit and short findings letter before quoting full design. It filters out clients who are only price shopping and gives you the information needed to price accurately.
Simple proposals for standard residential work are usually free. For a complex or uncertain job, such as a damaged structure, many engineers charge for an initial site visit, and credit that fee toward the full project if the client proceeds.
Quote the investigation as an hourly or fixed-fee first phase, then quote design once you have verified conditions. State in the proposal that hidden conditions may change the scope and fee.
Only if the client signs or accepts it, and the terms are clear. Many engineers use a proposal with terms and conditions that the client signs, covering scope, fee, payment terms, and limits of liability. Have an attorney review your standard terms.
Thirty days is common. Include an expiration date so you are not held to old pricing if the client comes back months later or the project scope changes.
Use the Structural Engineer invoice template to bill the client, or convert this estimate once it's approved.
Structural Engineer invoice template