Construction Drawing File Storage and Sharing: NAS, SharePoint or Both?
Large drawing sets and BIM models break cloud sync in predictable ways. Where each project file should live, and what backs it up.
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Construction drawing file storage works best in two layers. Active models and drawing sets belong on the fastest storage the people editing them can reach, usually a NAS on the head-office network. Issued drawings, site reports and correspondence belong in SharePoint, where site teams, consultants and clients can reach them. Both layers need a separate, tested backup.
Key takeaways
- Active CAD and BIM files want fast local storage; issued and archived sets want the cloud. Most contractors need both.
- Cloud sync tools struggle with large, cross-referenced drawing files, and a site cabin on mobile data makes it worse.
- RAID keeps a NAS running through a disk failure. It does nothing against deletion, ransomware or fire.
- SharePoint's recycle bin and version history are conveniences, not a backup. Back up the cloud layer separately.
- Decide before handover what each project's files become: an archived set, a retained record, or deleted on schedule.
Where should construction drawing file storage sit: NAS, SharePoint or both?
Active project files belong on the fastest storage the people editing them can reach, issued and archived drawing sets belong in the cloud where anyone with a right to see them can get them, and both need a backup that is separate from either. That is the short answer, and most of this article is about why the two halves cannot be collapsed into one.
The reason is that a contractor or consultant holds two very different kinds of file under the single word 'drawings'. The first is the live model or drawing set that a small team edits all day, often with dozens of referenced files that must all be present for the drawing to open correctly. The second is the issued set: a numbered revision, stamped and sent to the site, the client, the consultant and the authority, which must never change again. The first kind wants speed and locking. The second wants reach, permissions and a record of who saw what and when.
On most Dubai projects the people editing sit in one head office, usually in a tower with a fitted comms room, while the people consuming are spread across site cabins on mobile data, consultants in other emirates and a client's representative who wants the current set on a tablet. A single system rarely serves both groups well. Our guide to IT support for construction companies covers the wider picture; this piece stays on the files.
Why do drawing files misbehave in cloud sync tools?
Sync tools were built for documents that stand alone and that one person edits at a time. Drawing and model files are neither, and the failures follow directly from that mismatch.
The first problem is references. A drawing often points to other files: base plans, title blocks, linked models, images. Sync tools copy files individually and in whatever order they arrive, so a colleague can open a drawing whose references have not finished syncing and see missing content or a stale version, with no warning that the set is incomplete.
The second is locking. On a file server, when one engineer opens a drawing the software can take a lock so that a second person opens it read-only. Sync tools generally cannot enforce that across machines, so two people edit the same file, both save, and the tool quietly creates a conflicted copy. Someone then has to work out which version holds which changes, usually the evening before a submission.
The third is size and connection. Large files re-upload in full or in large part on every save, which is tolerable on a head-office fibre line and painful in a site cabin on a mobile router shared with everyone in it. Partial syncs, a laptop closed mid-upload and a folder with a very large number of small files all produce the same symptom: the site team is not looking at the drawing head office thinks it sent. The cabin side of that is covered in our post on site office internet setup.
The usual workaround, sharing large CAD files by email attachment or through personal file-transfer links, is worse than any of the above. There are no permissions, no revision record, and the file lives in whichever inbox happened to receive it.
When does a NAS at head office win?
A NAS at head office wins when the people editing large models sit in one office and reach it over a wired network. That describes most design teams and most contractors' technical departments, and for that group a well-built NAS is faster and calmer than anything in the cloud.
The reasons are the mirror image of the sync problems. Files open in place, so references resolve because they are all on the same volume. File locks work, so the second person to open a drawing knows it. Saves write once, over a local link, rather than uploading. Permissions follow project folders, so a subcontractor's engineer given a login sees one project and nothing else.
It comes with conditions. The NAS is only as fast as the network between it and the desk, so it needs proper switching and cabling: a design team plugged into an old switch through patch leads from the nearest hardware shop will blame the NAS for what the cable is doing. It needs a comms room that stays cool through a Dubai August, because disks age quickly in a hot cupboard. And it needs to be sized for current data plus three years of growth, which is how Listonics sizes them, because a model archive only ever grows. Our comparison of Synology and QNAP for a Dubai business covers choosing the unit itself.
One thing a NAS is not is a backup of itself. RAID keeps the volume running when a disk fails, which is what Synology's own explanation of what RAID protects against describes, and that is the whole of it. A deleted folder, a ransomware infection that encrypts every share, or a fire in the tower are copied faithfully to every disk in the array. A NAS for a construction company bought as a single unit with no second copy anywhere is the configuration to avoid.
When does SharePoint or OneDrive win?
SharePoint wins for issued drawings and for anything that must be reached from a site cabin, by a consultant or by the client, with a record of who changed what. That is a large share of a project's files, and for those files it beats a NAS comfortably.
What it does well: an issued set uploaded once to a project library is available from any browser, including a tablet in a cabin on a mobile router that could never open a live model. Version history shows every revision and who uploaded it. Guest access lets a consultant's engineer see one library under their own company login, which can be removed the day they leave the project, rather than a shared password that outlives everyone who knew it. Drawing number, revision and status can be columns in the library rather than a naming convention nobody follows. Using SharePoint for drawings in this role, as the issue and distribution layer, is the right use of it.
Now the honest limits. It is not a file server. Opening a live, referenced model directly from a synced SharePoint library brings back every problem from the previous section, and the path-length and throttling limits that come with any large cloud library surface exactly when a project folder gets deep and busy. Consultants and clients also bring their own tenants and their own rules, so external sharing needs to be set deliberately, project by project, rather than left at the default.
And it is not a backup. Microsoft's guidance on restoring items from the site collection recycle bin is clear that deleted items are kept there only for a limited period before they are gone for good, and version history disappears with the file it belonged to. If a departing engineer deletes a project library, or a ransomware infection on one laptop encrypts a synced folder and syncs it back up, the platform's built-in recovery is a convenience, not a plan.
What does a workable hybrid look like?
A workable hybrid puts live editing on the NAS, issue and distribution in SharePoint, one backup covering both, and a written rule for which file goes where. The rule matters more than the equipment: without it, staff will pick whichever location happens to be open on their screen.
The flow on most projects looks like this. The design or technical team works on the NAS. When a set is issued, the issued files are exported and uploaded to the project's SharePoint library, where site staff, the consultant and the client pick them up. Site photos, daily reports and inspection records are created on site and go straight to SharePoint, because they come from phones and tablets that will never see the NAS. Contracts and correspondence live in SharePoint and mailboxes. When the project closes, the NAS project folder is archived once and the SharePoint library is set read-only.
Moving an existing shared drive into this shape is a project in itself. Microsoft's Migration Manager can copy file shares into SharePoint in bulk, which suits the issued and correspondence layers; the live model folders should be moved to the NAS by hand, project by project, so references and folder structure survive. Do the move over a Saturday and Sunday when nobody is editing, and keep the old share read-only for a month afterwards so anything missed can be recovered.
| File type | Primary location | Backup |
|---|---|---|
| Active models and working drawings | Head-office NAS on the wired network | Nightly copy to a second device or cloud storage, kept off the office network |
| Issued drawing sets | SharePoint project library, read-only once issued | Separate Microsoft 365 backup, plus the archive copy on the NAS |
| Site photos, daily reports and inspections | SharePoint or Teams, uploaded from site devices | Separate Microsoft 365 backup |
| Contracts and correspondence | SharePoint and mailboxes | Separate Microsoft 365 backup with a retention period agreed with the contracts side |
| Archived projects | Read-only archive on the NAS or cold cloud storage | A second copy in a different location, restore-tested every year |
How should project files be backed up and for how long?
Project files should be backed up so that three copies exist on two different kinds of storage with one of them somewhere else, the restore should be tested rather than assumed, and the retention period should be agreed before handover rather than discovered afterwards. That is the 3-2-1 principle in plain words, and it applies to the NAS and the cloud layer alike.
For the NAS that usually means a nightly copy to a second NAS in another location, or to cloud object storage, with the copy job arranged so that a ransomware infection on the office network cannot reach the backup and encrypt it too. For SharePoint, OneDrive and mailboxes it means a separate backup product, because the platform's own tools were not designed to be one. Microsoft now sells Microsoft 365 Backup as a distinct service covering SharePoint, OneDrive and Exchange, which is the clearest signal that the built-in recycle bins were never meant to carry that job.
Test restores. A project file backup that has never been restored is a hope. Once a quarter, pick a project folder and a drawing from some months back, restore them to a different location, time it, and check that the references open. Our post on backup that actually restores goes through the routine, and our business backup services page sets out what a managed arrangement includes.
Retention is a business decision, not an IT one. Defects liability periods, the records you may need in a dispute and what the client's contract requires all set how long a project's files must be kept after handover, and those are questions for your contracts and legal side. What IT should do is make the answer cheap to honour: an archived project on cold storage costs little to keep and a great deal to recreate. Keep the issued sets, the as-built drawings, the correspondence and the final models. Working files and superseded revisions can usually go once the archive is verified, but confirm that against your own obligations before deleting anything.
How Listonics helps with construction drawing file storage
Listonics designs and installs the storage layer that drawing and BIM workflows sit on: a Synology or QNAP NAS sized for current data plus three years of growth, the switching and cabling that let a design team open models from it at full speed, a SharePoint structure for issued sets and site records, and a backup covering both with tested restores. We do not supply or manage CAD, BIM or project-management software; we build the network, devices, identities and backups those tools depend on and coordinate with their vendors. Every engagement starts with a free site survey and assessment. Projects are quoted as fixed-scope, itemised proposals, and ongoing support is a fixed monthly fee per user or per device. See NAS storage and backup for the service scope, or contact us to book the survey.
Frequently asked questions
Issued drawings, yes: that is exactly what a SharePoint library is for. Live, referenced models, generally no. Opening them from a synced cloud folder brings sync conflicts, broken references and lost file locks. Keep active editing on a NAS or file server over a wired network, and publish issued sets to SharePoint.
If your team edits large, cross-referenced drawing and model files in one office, usually yes. OneDrive suits personal working files and documents. A NAS gives the design team file locking, references that resolve and saves over a local link. Many firms run both, with a written rule for which file goes where.
No. RAID keeps a NAS running when one disk fails, which is useful, but it copies deletions, ransomware encryption and corruption to every disk just as faithfully. Project files also need a separate backup on different storage, ideally in a different location, with restores tested on a regular schedule.
Through SharePoint, not the NAS. Issued sets uploaded to the project library open in a browser or the mobile app on a tablet, at a size a mobile router in a cabin can handle. Keep live models at head office and publish issued revisions only, so the site always sees a numbered, stamped set.
Archive them once, deliberately. The NAS project folder becomes a read-only archive with a second copy elsewhere, and the SharePoint library is set read-only with external guests removed. Agree the retention period with your contracts and legal side before handover, and record where the archive is so it can be found years later.
Size it for the data you hold today plus three years of growth, measured from your existing shares and archive rather than guessed. Model files and site photos grow faster than most firms expect. Leave empty drive bays where you can, so capacity can be added without replacing the unit or migrating everything again.
Written by Srinivasan Ramachandran, Founder, Listonics · Published Sep 24, 2026 · Last reviewed September 24, 2026 · 2,439 words
