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The Project Wrapped in September. Your Data Obligations Didn't.

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Quick answer

When a construction or engineering project closes out, the drawings, models, contracts, and correspondence behind it don't stop mattering — they become records you may be legally and contractually required to keep, sometimes for a decade or more. In Ontario, the Limitations Act sets a general two-year limitation period but an ultimate 15-year cutoff for many claims, and construction contracts routinely demand as-builts and project data on handover.

Fall is peak closeout season in the Greater Toronto Area, which makes September the right time to archive project data properly instead of leaving 400 GB of files on a project server nobody maintains. CairiTech, an Aurora, Ontario managed IT provider, helps Architecture, Engineering, and Construction (AEC) firms archive completed-project data so it's secure, findable, and defensible years later.

3 min read posted on 09/13/26

What does "project data retention" actually mean?

Project data retention is the practice of deciding what completed-project files you keep, for how long, where, and how you'll find them again. For an AEC firm that means more than the final Revit model or AutoCAD drawing — it's the shop drawings, RFIs, change orders, submittals, site photos, contracts, and email trail that prove what was designed, approved, and built. A Common Data Environment (CDE) — the shared platform where a project's information lives while it's active — keeps this organized during the job, but retention is about what happens after everyone moves on to the next build.

How long do Ontario firms have to keep project records?

Longer than most firms plan for — often well beyond the life of the project. Ontario's Limitations Act, 2002 creates a basic two-year limitation period once a claim is discovered, but an ultimate limitation period of 15 years, meaning a defect or dispute can surface many years after handover. Contracts frequently impose their own requirements, and tax and corporate records carry separate timelines under the Canada Revenue Agency's six-year rule. The practical takeaway: if a roof leaks or a structural question arises in year eight, the firm that can instantly produce the stamped drawings and approvals is in a very different position than the one whose files vanished with an old laptop.

Why is keeping data on the project server a bad idea?

Because a live project server is built for active work, not decade-long safekeeping, and completed-project data quietly rots there. Old files sit on aging drives that fail, on systems that stop getting patched, and in folder structures only the departed project lead understood. Building models are large — a single coordinated BIM project can run into hundreds of gigabytes — so teams delete "old" projects to reclaim space, or leave them exposed on a share that no longer has proper access controls. That's the same lost-work risk we covered in Three Engineers, One Revit File, and a Monday Full of Lost Work — only now it's your legal record, not just a Monday.

What does a proper project archive look like?

A proper archive is a deliberate, secured, documented copy of the finished project — not just leftover files. The essentials:

A defined retention schedule per project type, so everyone knows what's kept and for how long.
Immutable, backed-up storage — ideally following the 3-2-1 rule (three copies, two media types, one off-site), so a ransomware hit or a failed drive can't erase the record.
Access controls that lock the archive to read-only for most staff, protecting it from accidental edits and deletion.
A searchable index — project name, address, dates, key files — so a request years later takes minutes, not a weekend.
A native-plus-neutral format plan (e.g., the Revit or AutoCAD file plus a PDF/IFC copy) so the data is still openable when the software has moved on.

Archive or delete — how do you decide?

Decide by matching each project's data to its real obligations and value, not by whatever frees up disk space fastest. Here's the shape of that decision:

Data type

Typical action at closeout and why

Final models, drawings, as-builts

Archive (long-term). Why? Legal record; needed for future disputes and renovations.

Contracts, change orders, approvals

Archive (long-term). Why? Limitation and contractual obligations.

Superseded working revisions

Cull, keep a milestone set. Why? Storage bloat; final versions carry the record.

Temporary render caches, duplicates

Delete. Why? No evidentiary or reuse value.

Client personal / financial data

Archive securely or purge per policy. Why? Privacy obligations under PIPEDA.

Close the project — and close the loop on its data

The end of a build is a natural finish line, but the paperwork and models behind it are still doing a job: proving what you designed and built if anyone ever asks. A simple, repeatable archive process turns that obligation from a liability into a quiet strength. If your finished projects are scattered across servers, drives, and cloud folders, a specialist can help you consolidate and secure them. Book your free discovery call with CairiTech today.

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Frequently asked questions

How long should a construction firm keep project files in Ontario?

Plan for the long end — often 15 years or more. Ontario's ultimate limitation period runs to 15 years, contracts may demand longer, and tax records follow the CRA's six-year rule, so a conservative retention schedule protects you.

Is cloud storage enough to protect archived project data?

Only if it's backed up and access-controlled. A single cloud copy can still be deleted, encrypted by ransomware, or lost with an account, so a proper archive follows the 3-2-1 backup rule and locks the archive to read-only.

What's the difference between a backup and an archive?

A backup protects active data you're still using; an archive preserves finished data you must keep. Backups are overwritten on a cycle, while an archive is a stable, long-term record you rarely change — you need both.

Can we delete a project once it's built?

Not safely, in most cases. Between limitation periods, warranty windows, and potential renovations, deleting a completed project's records can leave you unable to defend a claim or answer an owner years later.

Written by the CairiTech team — Greater Toronto Area managed IT and cybersecurity specialists, serving Ontario businesses (including AEC firms) since 1990. Head office: 1-2 Vata Court, Aurora, ON. Phone: +1 (416) 361-1441.

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