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Pre-works condition · neighbouring properties

Did this crack exist before the works?

A crack reported three months into a building site raises a simple question: was it already there before the works? Without dated documentation of the initial state, answering it objectively becomes difficult. Sealway lets you photograph the existing condition and bind those photographs to a qualified electronic timestamp, before the first shovel goes in.

Join the waitlist What to photograph before a site

Built for

  • Building contractors and tradespeople
  • Project managers
  • Developers and builders
  • Project owners
  • Property managers and landlords
  • Homeowners

A neighbour reports a crack. What can you produce?

Extension, heavy refurbishment, demolition, earthworks, new build, façade renovation, foundations, roadworks, works in common areas: the intervention changes the immediate surroundings.

A few weeks after the start, a neighbour states that a crack has appeared because of the site. The property manager passes on a claim. The insurer asks for material. The question becomes: did this crack already exist before the works started?

If nobody documented the initial state, the answer rests on memories and assertions. Before an expert or a court, asserting is not proving.

The applicable law: référé préventif, commissaire de justice’s report, proof by any means.

Three tools exist in France to fix the condition of the premises before a site. They differ in reach and in cost, and do not exclude one another.

Code de procédure civile, art. 145

The référé préventif

The référé préventif is not defined by a text of its own: it is construction practice’s use of the pre-trial evidentiary measure of article 145 of the Code de procédure civile. Where there is a legitimate reason to preserve or establish, before any trial, evidence of facts on which the outcome of a dispute could depend, the legally admissible evidentiary measures may be ordered at the request of any interested party, on application or in summary proceedings; since 1 September 2025, when the measure concerns a building, only the court of the place where the building stands has jurisdiction. The project owner thus has a court-appointed expert designated, who records, with all parties present, the condition of the neighbouring buildings before the start, then again when a defect is alleged. Service-Public.fr notes that the application is made by writ and that the expert is a sworn technician.

Constat de commissaire de justice

The commissaire de justice’s report before works

The Chambre nationale des commissaires de justice describes the pre-works report as an inventory of the condition of the adjoining properties or of the road near the future site, which prevents a site from being blamed for pre-existing damage. The report records the material findings made in person by a public and ministerial officer; in civil matters it stands unless the contrary is proven, and it gives a certain date.

Code civil, art. 1358 et seq.

Proof of facts by any means

Service-Public.fr puts it plainly: when the reality of a fact or of a situation has to be proven, proof may be given by any means, photographs included. Documentation built by the contractor itself is admissible. Its weight depends on what establishes its date and its integrity, and the court assesses it freely.

Paris Court of Appeal · 30 October 2019 (appeal dismissed: Cass. 3e civ., 17 Nov. 2021, no. 20-14.366)

Cass. 3e civ., 17 Nov. 2021, no. 20-14.366

Appeal dismissed without special reasons · judgment under appeal: Paris Court of Appeal, 30 October 2019

A dispute over the condition of premises at the end of a building lease. The former occupant argued that the deterioration recorded by the court-appointed expert was due to the next occupant’s intensive use, and produced aerial photographs. The Paris Court of Appeal set them aside for want of a certain date, and held that the expert had recorded the state of deterioration before the new occupant arrived.

Asserting is not proving, however, and aerial photographs of the premises, without a certain date, cannot suffice to provide that proof.

Reasons of the Paris Court of Appeal, reproduced in the decision; the appeal was dismissed without special reasons (art. 1014 of the Code de procédure civile). Our translation.

What Sealway takes from it

A photograph without a certain date does not settle a question of priority.

Read the decision on the Cour de cassation website (in French) →

What to document before the first shovel goes in.

The principle: photograph the existing condition systematically, area by area, with reference marks, then create the proofs before the start.

What to photograph

  • the façades of the neighbouring buildings, in a general view then bay by bay;
  • the party walls, from both sides where access is possible;
  • each existing crack, in a close-up with a scale reference and a wider view placing it;
  • floors, slabs, terraces and coverings;
  • fences, gates and low walls;
  • the common areas the site passes through: hall, staircase, courtyard;
  • the road, pavements, accesses and visible networks;
  • sensitive structures: manholes, pipes, plantings, street furniture.
  1. 1

    Locate and number the areas

    A location plan, even a rough one, shows where each photograph was taken from. Attach it to the proof.

  2. 2

    Photograph from the app

    General view, placing view, close-up. A short video can complete a large area, filmed from the app or imported, with no duration limit, within 250 MB per proof.

  3. 3

    Create the proofs by area

    Up to 10 files per proof. One proof per façade or per area stays readable later; group them in a collection named after the site.

  4. 4

    Keep the evidence files and the originals

    Download each evidence file and keep it with the location plan of the area; without a storage subscription, Sealway keeps the originals for 7 days.

Before works: initial state documented Sealway proof Works New documentation Sealway proof Comparison

The proof does not determine the origin of damage. It documents the visible condition of a place on a given date. It is the comparison between two dated states and, where needed, an expert’s opinion that make it possible to reason about the cause.

Example: heavy refurbishment of a terraced building.

  1. Before works

    Initial state

    28 photographs of the neighbouring façades, 6 of existing cracks, the shared courtyard, a video of the fence and a location plan, spread over five Sealway proofs.

  2. Day 90

    Claim

    The neighbour reports a crack on the party wall and blames the site.

  3. Same day

    New documentation

    The area is photographed again, from the same viewpoints. New proof.

The earlier proofs make it possible to check whether this crack was already visible before the site, whether it looks different, and whether the area had been documented. They do not say why the crack changed, if it did.

If the area had not been photographed, the proofs say nothing about its initial state: they only establish what was documented, and when. Hence the value of systematic rather than selective documentation.

Référé préventif, commissaire de justice’s report, Sealway documentation.

Three levels, suited to different stakes. On a large project, they add up.

Comparison of the measures that fix the condition of neighbouring properties before works
Measure Who records Reach When to use it
Référé préventif (CPC, art. 145) A court-appointed expert, with all parties present. Findings made with the summoned neighbours present; the expert can be called back if a defect appears. Large or high-risk operations: demolition, deep foundations, sensitive party walls.
Bailiff’s report (constat de commissaire de justice) A public and ministerial officer, in person. Stands unless the contrary is proven; certain date. High-stakes sites, exposed neighbours, precise areas to fix.
Sealway documentation The contractor, the project manager or the project owner themselves. Date and integrity of the files established by a qualified third party; the content remains the party’s own record. Every site, alongside the measures above, for the areas they do not cover and for regular follow-up.

The costs are not comparable either: a référé préventif means court proceedings and a deposit for the expert’s fees, a commissaire de justice’s report is quoted on request, a Sealway proof costs €1.99.

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 the visible condition of the area, existed as they are on that date, what they depict remaining a matter of assessment;
  • for a live capture, the shooting context recorded by the device.

Sealway does not, on its own, establish

  • the origin of a crack or of damage;
  • that a defect is attributable to the site;
  • the condition of areas that were not photographed;
  • the compliance of a neighbouring structure or of the works carried out;
  • what a court-appointed expert or a commissaire de justice would record.

The cause of a defect is a matter of technical analysis, and where needed of an expert report. A Sealway proof fixes dated states an expert can compare.

What a qualified timestamp changes for the condition of the neighbouring properties.

A photograph of a façade taken before the site is only worth something if it can be established that it does date from before. When the proof is created, the fingerprint of each file is bound to a qualified electronic timestamp issued by a qualified trust service provider.

  • 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

Before a site, what contractors, project managers and the neighbours themselves ask.

Why photograph the neighbouring properties before a site?
Because a defect reported during or after the works, a crack, subsidence, damage, will be blamed on the site if nothing establishes that it already existed. Dated documentation of the initial state gives a point of comparison; without it, the discussion rests on assertions.
Is a photograph enough to prove that a crack existed before the works?
A photograph is admissible evidence, but its weight depends on what establishes its date and its integrity. A court of appeal set aside photographs “without a certain date” produced to attribute damage to a third party. A photograph bound to a qualified electronic timestamp establishes that it existed, in this form, on that date: that is what a phone photograph lacks.
Does Sealway replace a référé préventif or a commissaire de justice report?
No. A référé préventif has the condition of the neighbouring properties recorded by a court-appointed expert, with all parties present; a report rests on the personal findings of a commissaire de justice, which stand unless the contrary is proven. A Sealway proof is built by the party itself, with a date and an integrity established by a qualified third party. It adds to those measures on the areas and periods they do not cover, and remains the reference documentation on sites that do not warrant them.
Should proofs be repeated during the works?
Yes, at the stages where the surroundings change: after the earthworks, after the foundations, before and after a demolition phase, and as soon as a defect is reported. Each proof carries its own date; end to end, they document the evolution.
Why is a qualified electronic timestamp different from a photograph’s EXIF date?
The EXIF date is written by the device and can be changed by software; it enjoys no presumption. A qualified electronic timestamp is issued by a qualified trust service provider and enjoys, under article 41 of the eIDAS Regulation, a presumption of the accuracy of the date and time and of the integrity of the data to which it relates.
Who can use this kind of proof?
The contractor carrying out the works, the project manager, the professional or private project owner, a property manager for the common areas, a neighbour who wants to document their own property before an adjoining site. The certificate identifies the depositing account of each proof (name or verified email address).

References

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

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.

Next, during the works.

Document the important stages of the works, then the acceptance. And remember the permit display, which is documented from the day the notice board goes up.

Site progress and follow-up

Build a dated chronology of the state and progress of the site at the important stages, before they are covered up.

Learn more →

Acceptance of works and reservations

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

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 →

Document the existing condition before the first shovel goes in.

Façades, party walls, cracks, floors, roads: one proof per area, dated by a qualified third party, to compare on the day a claim arrives. Join the waitlist to be notified at launch.

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