What should we do with drawings and models when a project ends?

Practical completion is not the end of a project’s paper trail. A claim, a query from a later owner or a question about what was issued can arrive many years later, and your practice will need to show exactly what it issued and when.

So when a project ends, move a complete, read-only record of it into a separate archive. Keep it for at least as long as a claim could be brought, keep it in formats you can still open, and protect it from deletion and ransomware. Then delete what you no longer need.

Why does a finished project still matter?

Because the law gives clients and others years to bring a claim, and your defence depends on your records. RIBA notes that project records “can be critical evidence in defending negligence, contract and building safety claims”, and that standard limitation periods do not always mark the end of an architect’s exposure.

Your insurance works the same way. Professional indemnity policies are written on a “claims-made” basis, so the policy in force when the claim is made is the one that responds, not the one in force when the work was done (ARB: professional indemnity insurance guidance). An old project can surface at any renewal.

How long should we keep project files?

In Northern Ireland the main time limits come from the Limitation (Northern Ireland) Order 1989:

• Contract claims: six years from when the cause of action accrued.
• Tort claims, including negligence: six years.
• Contracts signed as a deed or under seal: twelve years (Limitation (NI) Order 1989, article 15).
• Hidden defects (latent damage) in negligence: six years from accrual, or three years from when the claimant had the knowledge needed to sue, whichever ends later.
• The longstop: a negligence claim not involving personal injury cannot be brought more than fifteen years after the negligent act or omission, even if the damage hasn’t yet been found.
• Dwellings: anyone taking on work in connection with providing a dwelling must do it in a professional manner. Claims under that duty now have fifteen years from when the right of action accrued, extended to thirty years where the right arose before the Defective Premises Act (Northern Ireland) 2024 took effect.

In England and Wales the periods are similar (Scotland has its own rules). The Limitation Act 1980 gives six years for contract and tort, and twelve for deeds, and the Latent Damage Act 1986 added the same three-year knowledge rule and fifteen-year longstop. Defective Premises Act claims there also have fifteen years, or thirty for older rights. ARB’s guidance flags deeds and Defective Premises Act claims as liabilities that run beyond the normal limits, and RIBA notes residential projects may need records kept “for decades”.

The practical answer: set a retention period per project type, with fifteen years as a floor and longer for residential work, and agree it with your solicitor and insurer. If you ever close or sell the practice, ARB expects at least six years of run-off cover; the records need to outlive that too.

What belongs in the archive?

The record of what you issued and agreed, not every working file. As a minimum:

• Every issued drawing and model, at each revision, as issued.
• Issue registers and transmittals showing who received what, and when.
• Correspondence, including email, with the client, contractor and consultants.
• Instructions, variations and sign-offs.
• Planning and building control approvals, with their conditions.
• Appointment documents and any deed.

Will we still be able to open the files in fifteen years?

Only with planning. Autodesk states that Revit cannot save to older formats, and an older Revit release cannot open a newer file. Open an archived model in a newer release and it upgrades automatically; once saved, the earlier release can no longer open it. AutoCAD saves in the DWG format current at its release by default.

So archive in layers:

• Issued sets as PDF. This is the record of what you actually issued. PDF/A is the ISO standard version of PDF for long-term preservation.
• Native files (RVT, DWG) as they stood at issue, with a note of the software version used.
• An IFC export of the final model. IFC is an open international standard for building information, and Revit exports it. It won’t replace the native model, but other software can read it.

How do we stop the archive being changed or lost?

• Make it read-only. Nobody should be able to edit an issued record or save over an archived model. Microsoft 365 can also declare items as records, which blocks deletion and logs activity, but that needs a higher licence than Business Premium.
• Limit who can see it. A small named group, not the whole practice. Our guide to protecting drawings and design work covers access in more depth.
• Keep it out of live storage. Mixing closed and live projects can slow searches and sync; see what slows IT down in an architecture practice.
• Back it up separately. The NCSC says backups should resist destructive actions: once created, they shouldn’t be deletable or alterable, even by an attacker using your own admin accounts, and retention should be set by time. Our guide to whether your Microsoft 365 backup will work explains how to test it.

What about personal data in old project files?

Project files hold names, addresses and contact details, and sometimes more. UK GDPR says personal data should be kept no longer than necessary, and the Information Commission (formerly the ICO) says you shouldn’t keep it “just in case”. Keeping records to defend possible claims is a valid reason, but data should be deleted once such a claim could no longer arise.

So archive the project record, not everything. Put a review date on each archived project, and delete or anonymise when it passes.

Who owns the archive when people leave?

The practice, never an individual. Archives in personal OneDrives or on an old office server go missing when people leave. Name one partner as owner, keep the archive in a practice-owned location, and record what is there and each project’s review date. Our guide to what happens when a key person leaves covers the wider risk.

Whoever runs your IT, in-house or outsourced, should set up the archive and test that it can be restored; a partner should own the retention rules.

Related: Managed IT for professional firms

Frequently asked questions

Can we just keep everything forever?

Not if it contains personal data. UK GDPR requires you to keep personal data only as long as necessary, so set a retention period and review it. Keeping the project record for the claim period is fine; keeping everything indefinitely is not.

Is a PDF of the issued drawings enough?

It is the most reliable record of what you issued, and it will open for years. Keep the native models and an IFC export as well, because a dispute may turn on information that only the model holds.

Does the clock start at practical completion?

Not always. Limitation periods run from when a cause of action accrues, which depends on the claim, and the latent damage rules can extend them. Take legal advice on your own appointments, and set retention from the latest date that could apply.