An as-built drawing is the permanent record of what was actually constructed. Every construction project of any significance produces one — or should. As-builts protect owners, support future modifications, satisfy permit requirements, and protect contractors from warranty disputes. This guide explains what they are, who needs them, and how to generate them efficiently in the field.
What is an as-built drawing?
An as-built drawing is a set of construction drawings updated to reflect what was actually constructed, rather than what was originally designed. As-builts document all deviations from design — changed dimensions, relocated utilities, adjusted elevations, and substituted materials. They are the permanent record of the constructed facility, required by public agencies, EPCs, and private owners at project closeout.
An as-built drawing documents the difference between design intent and construction reality. Construction projects almost never build exactly what was designed — field conditions, material substitutions, contractor decisions, and engineer-directed changes all produce conditions that differ from the original drawings. As-builts capture these differences permanently.
Typical elements documented in as-built drawings include:
| Owner / Authority | Format Required | Certified By | Timing |
|---|---|---|---|
| Municipal public agency (sewer/water) | CAD drawing + GIS shapefile | Licensed civil engineer or surveyor | Within 30-90 days of acceptance |
| State DOT (road project) | CAD drawing + digital data | Licensed PE on contractor staff | At substantial completion |
| Solar EPC | PDF + DWG pile layout, grading as-built | Contractor QC superintendent | Within 30-60 days of MC |
| Private building owner | PDF (typically) | Contractor (engineer optional) | At project closeout |
| Lender / title company | Survey plat or drawing | Licensed land surveyor | Before final loan disbursement |
Most contractors generate as-built drawings at the end of the project — after all the underground work is buried, all the concrete is poured, and all the crews have moved on. This is the worst possible time to generate an as-built, and it is the primary reason as-built quality is poor on most projects.
When you reconstruct as-built conditions after the fact:
The solution is to capture as-built data during construction — as each feature is installed, before it is buried or covered. Data captured at installation is accurate and takes 30-60 seconds per measurement. Data reconstructed at closeout is approximate and takes hours of engineering time.
The most efficient as-built generation process works concurrently with construction, not sequentially after it:
The specific content of an as-built drawing varies by project type. The core principle is the same — document what was built — but the critical data elements differ:
Critical data: manhole coordinates and rim/invert elevations, pipe slope, pipe depth, lateral locations and depths, valve locations and depths. See our guide on how to document utility as-builts for city acceptance.
Critical data: as-driven pile locations and elevations, grading as-built (finished grade surface), inverter pad locations and elevations, collection system cable and conduit routing. See our solar farm grading documentation checklist.
Critical data: finished grade elevations along centerline and lane edges, cross-slope at each station, base and subgrade elevations, culvert locations and inverts, drainage structure locations. See our guide on how to document road base elevations.
Critical data: pad elevations, finished grade across lots, swale flowline elevations, detention basin floor and berm crest elevations, cut/fill volumes. See our guide on cut and fill documentation best practices.
An as-built drawing is a construction drawing updated to reflect what was actually constructed — including all deviations from the original design. Also called record drawings, they document actual dimensions, elevations, pipe locations, and material substitutions. Required by public agencies, EPCs, and private owners at project closeout.
The terms are used interchangeably in most contexts. When a distinction is drawn, "as-built" refers to the contractor's field-marked drawings, while "record drawings" refers to the engineer's final certified drawings prepared from the as-built markups. The practical difference is that record drawings carry the engineer's professional certification.
Public agencies (city, county, state DOT) require as-builts for infrastructure improvements as a condition of permit acceptance. EPCs require them for energy projects at substantial completion. Private owners require them as a contract deliverable. Lenders and title companies require them for facilities finance. The format and certification requirements vary by owner.
The best practice is to capture field measurements during construction — as each feature is installed, before it is buried. Data is logged to a field documentation system, transferred to CAD at closeout, and certified by the project engineer. As-builts generated from field data captured during installation are accurate; as-builts reconstructed from memory after closeout are approximate.
Sitemark captures elevation data, pipe inverts, grade points, and deviations in the field as you build — so your as-built is built alongside the project, not reconstructed from memory at closeout. Start free.