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Site progress and follow-up

Site progress: this is what was visible on that date.

A contractor states that work was completed before a given date. A project owner considers that the site made no progress for weeks. An installation is about to be covered up and will never be visible again. In all three cases the question is the same: what could be seen, and when? Sealway turns a series of photographs into a chronology of independent proofs.

Join the waitlist See the chronology

Built for

  • Contractors and subcontractors
  • Site managers
  • Project managers
  • Project owners
  • Developers
  • Homeowners

The problem: proving the state of a site after the fact.

What a site shows changes every day, and some things will never be seen again.

Services disappear behind the partitions, reinforcement under the concrete, insulation behind the boards, pipes under the backfill. Once the site is finished, what was done can no longer be photographed. Disagreements about progress, about the state a trade left behind, or about what was completed on a given date are then settled on memories and on documents whose date is not established.

This is not a matter of scheduling, Gantt charts or invoicing. It is a matter of evidence: building a documented chronology of the works carried out and of the state of the site on different dates.

What the law expects of evidence of progress.

No text imposes a particular mode of proof for the state of a building site. Two general rules of French law are enough to understand what is at stake, and one mechanism to answer it.

Code civil, art. 1353

Whoever relies on a fact must prove it

The Code civil states the rule: whoever claims the performance of an obligation must prove it and, conversely, whoever claims to be released must prove the payment or the fact that extinguished the obligation. Service-Public.fr sums it up: in civil proceedings, the person who relies on a fact or on the existence of a right must prove it. The contractor invoicing progress, like the project owner disputing it, each have an interest in holding dated material rather than reconstructing after the event.

Code civil, art. 1358 et seq.

Proof of facts by any means

Unless the law provides otherwise, proof may be given by any means. When the reality of a fact or of a situation has to be proven, that includes photographs. The court assesses their weight freely: a photograph only carries weight if it can be established when it was taken and that it has not been altered.

eIDAS Regulation, art. 41(2)

The presumption attached to a qualified timestamp

A qualified electronic timestamp enjoys a presumption of the accuracy of the date and the time it indicates and of the integrity of the data to which it relates. That mechanism is what gives a site photograph a date that depends neither on the phone nor on the person producing it.

One proof at every stage that matters.

The useful rhythm is not daily. It follows the stages where the state of the site changes irreversibly, or where responsibility passes from one trade to another.

What to document

  • structural works: foundations, walls, floors, before each pour;
  • roof and façades;
  • services, ducts and cables before the partitions and ceilings are closed;
  • insulation and waterproofing before they are covered;
  • reinforcement before pouring, pipes before backfilling;
  • fit-out, equipment, finishes;
  • the state left by one trade before the next one starts;
  • the state of the site before an interruption, at restart, and after a requested change.
  1. 1

    Photograph from the app

    Overall view then detail views, with a location reference. The certificate shows for each file that it was captured live.

  2. 2

    One proof per stage

    Up to 10 files per proof. Name the proof by stage and by area: “1st floor services before closing in”, not “site photos”.

  3. 3

    Group by site

    One collection per project gathers the proofs in order. The chronology reads on its own.

  4. 4

    Keep

    One proof per stage, downloaded and filed in the site’s collection; without a storage subscription, the originals stay in Sealway for only 7 days.

Each proof carries its own date, established by a qualified third party, and each one is verified on its own.

A chronology of independent proofs.

Example on a detached house: each stage is a separate proof.

  1. 4 March

    Earthworks complete

    Platform, excavations, buried services before backfilling.

  2. 12 March

    Foundations

    Reinforcement in place before pouring, then footings poured.

  3. 28 March

    Walls up

    Walls built, lintels, ring beams.

  4. 15 April

    Services before closing in

    Ducts, cables, plumbing and insulation visible, before the boards.

  5. 30 April

    Partitions closed

    The previous state is no longer visible: the proof of 15 April stands in for it.

A chronology serves all the better for being regular and complete.

Five situations where the chronology makes the difference.

Works about to be covered up

Some works can no longer be photographed once the site is finished. A proof created before they are covered documents their visible state on that date, and stands in for it afterwards.

Overall progress

Structural works, roof, façades, fit-out, services, equipment, finishes: one proof per stage gives a dated reading of progress, for the contractor who invoices as for the project owner who follows.

Site interruption

The state of the site before the interruption, during it, and at restart: what was protected, what was exposed, what was redone.

Additional works and changes

Document the state at the moment a change is carried out, before it is reworked or covered up: what was done, and when.

Coordination between trades

Before a trade starts, photograph the state left by the previous one. If contractors disagree, each holds a dated record of what they found and of what they left.

Who this serves, concretely.

For the contractor

Document the works carried out, keep a record before covering up, fix the state handed over to another trade, build a technical archive of the site.

For the project manager

Complete the documentary follow-up, keep dated intermediate states, make it easier to reconstruct the chronology in case of disagreement.

For the project owner

Hold regular, dated records of the state of the site, independent of everyone’s progress reports.

Example: a disagreement over a plumbing package.

  1. 15 April

    Proof before closing in

    The plumber photographs the services awaiting closure and creates a proof: 8 photographs, 1st and 2nd floors.

  2. 30 April

    Partitions closed

    The drylining contractor closes up. The services are no longer visible.

  3. June

    Leak reported

    The project owner blames the plumbing; the drylining contractor mentions a puncture during the boarding.

The proofs of 15 April show the state of the services before closing in, on a date established by a qualified third party. They do not say who pierced what: the expert will determine that when opening up. But they fix a starting state nobody has to reconstruct from memory.

What Sealway proves, and what it does not.

Sealway makes it possible to establish

  • that a given photograph or video existed on the date of the timestamp;
  • that the file presented later is identical to the one timestamped;
  • that these images, which show what was visible on the site, existed as they are on that date, what they depict remaining a matter of assessment;
  • a chronology, when proofs were created at each stage.

Sealway does not, on its own, establish

  • compliance with the DTU standards, with regulations or with the contract;
  • the technical quality of a structure or the proper execution of works that are not visible;
  • the real percentage of overall progress;
  • that a delay is contractually attributable to one party;
  • that additional work was ordered or accepted.

The court and, where one is appointed, the expert keep their role. A chronology of proofs gives them dated states to reason from.

What a qualified timestamp changes for site progress.

A site photograph taken with a phone carries a date the device wrote. When the proof is created, the fingerprint of each file is bound to a qualified electronic timestamp issued by a qualified trust service provider: the date no longer depends on the phone.

  • SHA-512 fingerprint of each file: the proof bears on this exact version; modifying the file changes the fingerprint, and the fingerprint cannot be turned back into the file.
  • Qualified electronic timestamp: presumption of accuracy of the date and time and of integrity of the data (eIDAS Regulation, art. 41(2)). The date comes neither from the device nor from Sealway.
  • Evidence file verifiable without Sealway: certificate, manifest, timestamp token and fingerprints, with the references of the anchoring on public blockchains.
The mechanism in detail: create evidence from your files

Frequently asked questions

What site managers, project managers and project owners ask.

Why photograph a building site regularly?
Because the state of a site changes every day and some structures become invisible: closed-in services, poured reinforcement, backfilled pipes. A series of dated proofs fixes what was visible at each stage, for the contractor who has to justify its works as for the project owner who follows them.
How often should a proof be created?
At the stages that matter, rather than on fixed dates: before each covering up, at the end of each phase, before and after an interruption, at each handover between trades, and whenever a change is carried out. On a site lasting several months, that typically means a few proofs a week during active periods.
Can a photograph prove that work was carried out, or that it complies?
It establishes that what the image shows was visible on that date, not what does not appear in it. Compliance with the DTU standards or the contract, technical quality and the real percentage of progress are for the project manager, the technical inspection body or the expert. For work carried out and then covered up, the photograph is often the only visual material left, hence the value of dating it independently.
Does Sealway make it possible to prove a site delay?
Not on its own. Regular proofs establish the state of the site on different dates, hence what was or was not completed on each. Whether a delay is contractually attributable to one party depends on the contract, the works orders, the weather, the correspondence between the parties: that is a legal question, not a question of photographs.
Can several photographs be attached to one proof?
Yes, up to 10 files and 250 MB per proof: photographs, videos, PDFs, a report, a plan. One proof per stage and per area remains the most readable rule; the site’s collection puts them in order.
Does Sealway replace site-management software?
No. Sealway manages neither schedules, nor tasks, nor teams, nor invoicing. It builds dated proofs of the state of the site, which you can keep alongside your follow-up tool, whichever it is.
Can Sealway be used across several trades?
Yes. Each contractor creates its proofs from its own account: the state it finds on arrival, the state it leaves on departure. If trades disagree, each holds independent dated material, and the certificate identifies the depositing account of each proof.
Why not simply keep the photographs on a phone?
Because their date rests on metadata the device writes and software can change, and because nothing establishes that they have not been retouched or replaced. In another field, the display of building permits, the Conseil d’État accepted that a court disregard the date of photographs established by their metadata alone. Sealway keeps that metadata but rests the date on a qualified timestamp issued by a third party.

References

Texts and official documents cited on this page (in French).

  • Code civil, art. 1353 to 1357 (burden of proof) Légifrance →
  • Code civil, art. 1358 to 1362 (admissibility of the modes of proof) Légifrance →
  • Service-Public.fr, “Quels sont les modes de preuve dans un procès civil ?” service-public.gouv.fr →
  • Regulation (EU) No 910/2014 of 23 July 2014 (eIDAS), art. 41 EUR-Lex →
  • Conseil d’État, 5th chamber, 10 March 2025, no. 472387 (photograph metadata) ArianeWeb →

Sealway does not provide legal advice. These references are given for information; the evidential weight of the material produced is for the court to assess, after an expert report where one is ordered. The French official sources are in French.

At the end of the works, the acceptance.

Document the acceptance and the reservations as well. And if it is not done yet, the condition of the neighbouring properties before the start.

Acceptance of works and reservations

Document precisely the defects, imperfections or outstanding work at the moment of acceptance, then their lifting.

Learn more →

Pre-works condition and neighbouring properties

Photograph and date the condition of a building, a plot or the neighbouring properties before the works start.

Learn more →

Building permit display

Build timestamped evidence that your planning permission was displayed on site, and document its continuity over time.

Learn more →

The whole real estate and construction section →

Date every stage of your sites.

One proof before each covering up, at each handover: SHA-512 fingerprint, qualified electronic timestamp under eIDAS, evidence file verifiable by a third party. Join the waitlist to be notified at launch.

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