Where the 6 to 8 weeks actually goes.
"Six to eight weeks from sign-off" is what we put on most mezzanine quotes. It's not handwaving — it's a specific sequence of steps with predictable durations. Understanding what happens in each week is useful for planning around shutdown windows, peak-season delivery, and downstream construction trades.
Week 1: engineering & stamped drawings
Starts the day after sign-off. Detailed structural drawings, anchor design (if attaching to existing structure), connection design, and the engineer's stamp. Bill of materials goes to the shop on day 5 to lock in steel orders.
Variable: retrofit projects with existing-structure verification can run a few extra days while wall composition or slab capacity is checked.
Weeks 2 – 4: fabrication
Steel cut, drilled, welded, and assembled into shippable subassemblies. Traceability per joint. Quality inspection (visual + spot UT where required) per piece before finishing.
Variable: heavy-load classes (300 psf+) take more time; multi-tier mezzanines run 4 – 6 weeks rather than 3.
Week 5: finishing
Shop primer, hot-dip galvanizing, or powder-coat depending on spec. Galvanizing is sub-contracted and adds ~5 working days to the timeline. Powder-coat over galv adds another 3 – 5 days.
Variable: shop primer only — week 5 isn't needed; install moves up. Powder-coat over galv — adds nearly a week.
Week 6: pre-install verification & logistics
Pre-install walk at the site (see shutdown-coordinated install for detail). Confirms drawings vs current site state; resolves anything that's changed. Truck loading sequenced for the install plan; rigging plan finalized.
Variable: if the pre-install walk surfaces a real change (rare but does happen), this can extend.
Week 7: install
For a typical 6,000-sqft single-tier mezzanine, install runs 3 – 5 working days. Larger or more complex projects (multi-tier, exterior fire escape, equipment-platform integrations) run 5 – 10 days.
The install sequence per day is in the shutdown-install article.
Week 8 (sometimes): concrete pour & commissioning
For B-deck + concrete decks, the pour happens after structural is set — typically a separate trade running on day 4 – 5 of the install week or the following week. We coordinate the pour but the concrete itself is the contractor's scope.
Sign-off walk and handoff documentation (as-builts, load plate, inspection package) wraps up the week.
Where the timeline moves
- Faster: shop-primer-only finish (skip a week), bolt-together modular mezzanine (faster install), pre-fabricated stair access integrated into the mezzanine package.
- Slower: galvanized + powder-coat finish, multi-tier construction, retrofit anchor design into existing structure, cold-storage notch-tough steel (longer steel-mill lead time), regulated facility finish requirements (additional QA / paint cycles).
What's not in the 6 – 8 weeks
- Permit application time at the building department — see mezzanine permits in Ontario. The 6 – 8 weeks starts after sign-off, which generally happens after permit issue.
- Quote stage and site measure — typically 1 – 2 weeks before sign-off.
- Architectural design (if applicable) — runs in parallel but on the architect's timeline.
Emergency timelines
For straightforward stair-only retrofits (a fire-escape stair tower, a code-driven egress add) we can sometimes hit a 2 – 3 week timeline from sign-off if the queue allows. Mezzanines are harder to compress — the engineering and fabrication windows are real. Worth asking at quote stage if your timeline is tight; we'll be honest about whether it's possible.