Basis of Design Documentation: The Cost of Starting Every Project from Scratch

The Problem

MEP and AEC firms lose 20 to 40 percent of their working hours to non-billable activity. (Stambaugh Ness) BOD documentation sits squarely in that category. The hours spent assembling a BOD (pulling relevant code sections, recalling prior project criteria, formatting system descriptions, aligning with owner project requirements or OPR) are hours that don't show up on an invoice. For a document that most clients neither see nor understand the value of, the engineering time that goes into producing it is disproportionately high.

The deeper problem is inconsistency. When BOD documents are built project by project from memory or repurposed templates, engineering assumptions vary across the team. A senior engineer's approach to system selection criteria for a laboratory HVAC system may differ from a project engineer's interpretation of the same guidance. Terminology drifts. Standards get applied inconsistently. Those inconsistencies don't stay in the BOD. They migrate downstream into specifications, equipment schedules, and coordination drawings, where they generate RFIs, submittal rejections, and change orders that are expensive to resolve.

A 2025 report by Qualis Flow found that 95 percent of construction deliveries contain incomplete, inconsistent, or inaccurate documentation. BOD documentation is the origin point for much of that inconsistency. What gets documented imprecisely at the beginning of design gets interpreted imprecisely for the rest of the project.

What's Driving It

The BOD problem is not a skill problem. It is a process design problem. Most MEP firms do not have a defined, repeatable system for producing BOD documents. There is no standardized input structure, no template that pulls from verified code libraries, no mechanism for ensuring that project-specific assumptions are captured explicitly rather than left to interpretation.

The result is that every BOD is a custom document produced under time pressure by whoever is running that phase of the project. The senior engineer who knows the right approach may not be the one writing the document. The person writing it may not have access to the prior project history that would tell them which criteria were contested, which owner preferences are non-negotiable, and which code interpretations require care.

This is a documentation and knowledge management failure. The information exists in the firm. It is distributed across email chains, project files, and the heads of senior staff. It never gets systematically captured in a form that makes the next BOD faster, more consistent, or easier to validate.

What Resolution Looks Like

A well-structured BOD process treats documentation as a workflow, not a writing task. The distinction matters. A workflow has defined inputs, standardized outputs, and checkpoints. A writing task depends on the skill and memory of whoever is doing it that week.

AI tools can support this by pulling from verified code references and standards databases, cross-referencing prior project documentation to surface relevant criteria, and structuring input-gathering from the design team in a way that ensures completeness before drafting begins. The engineer still makes every technical decision. The system ensures those decisions are captured consistently, that no standard section gets overlooked, and that the resulting document is formatted and traceable before it leaves the team.

For a mid-size MEP firm producing 20 to 40 BODs per year, the compounding effect of consistent, thorough documentation is significant: hours recovered at the front end, and reduced downstream friction as the project moves through design, coordination, and construction.

QP brings a systems-discipline approach to this kind of workflow design. The same methodology that produces defensible documentation in regulated engineering environments, where an inconsistent record is a compliance failure, not just an inconvenience, produces consistently better records in MEP project delivery.

The Bottom Line

A BOD document that takes too long to produce and contains inconsistent assumptions doesn't just waste design hours. It seeds problems into every phase that follows. Addressing this workflow isn't a technology decision. It's a process design decision with a direct effect on project quality and firm efficiency.

If your current BOD process depends on memory and templates copied from the last job, that's worth examining before the next project starts.

Sources: Stambaugh Ness, Non-Billable Time in AEC Firms; Qualis Flow 2025 Construction Documentation Report