Typical MEP Engineering Timelines
MEP engineering timelines depend heavily on project size, system complexity, how complete the architectural documents are, and whether existing conditions need to be verified. Here are general benchmarks.
Small TI Projects (Under 5,000 SF)
A simple commercial tenant improvement — office fit-out, small retail, straightforward restaurant TI — typically takes two to four weeks from final architectural documents to permit-ready MEP drawings. Projects with rushed permit schedules can sometimes be accelerated, though schedule changes usually have cost implications.
Mid-Size Projects (5,000–20,000 SF)
Medical office fit-outs, multi-tenant retail, larger restaurant projects, and industrial TIs in this size range typically take three to six weeks for MEP engineering. Projects with complex systems (healthcare pressure relationships, extensive electrical loads, specialty exhaust) trend toward the longer end.
Large or Complex Projects
New construction, full building MEP systems design, data centers, hospitals, or multifamily buildings are eight to twelve weeks or longer depending on scale. These projects go through design development phases before the permit set — schematic design, design development, and then construction documents.
What Slows Engineering Down
- Architectural drawings that aren't complete or finalized when MEP starts
- Equipment selections not made — MEP engineers need to know what equipment is being installed
- Existing conditions that need field verification before design can begin
- Plan check comment responses — jurisdiction review times vary; some cities take 4–8 weeks for first review
- Design changes during engineering — scope changes restart portions of the work
How to Keep MEP on Schedule
Start MEP engineering as early as possible — ideally when architectural design development is 50–75% complete. Final architectural documents aren't required to begin MEP; preliminary layouts and confirmed equipment selections are enough to start. Late engagement of MEP engineers is the most common cause of schedule delays in commercial construction.