Faute de constater l’infiltration, l’expert ne peut pas évaluer le dommage.

Faute de is a fixed expression meaning for lack of, in the absence of, or sometimes because one failed to.

In this sentence, Faute de constater l’infiltration means something like:

• Because the expert did not detect/establish the infiltration
• For lack of having identified the infiltration

It is a fairly formal expression. You will often see it in written French, especially in technical, legal, or administrative contexts.

A useful pattern is:

• faute de + noun
• faute de + infinitive

For example:

• Faute de preuves, le juge ne peut pas décider.
  = For lack of evidence, the judge cannot decide.
• Faute de comprendre la question, il n’a pas répondu.
  = Because he failed to understand the question, he did not answer.

After faute de, French often uses the infinitive when the idea is for lack of doing something.

So:

• faute de constater l’infiltration

literally means:

• for lack of observing/establishing the infiltration

This is very normal French structure.

Also, the subject of constater is understood to be the same as the subject of the main clause: here, l’expert. So the sentence implies:

• L’expert ne peut pas évaluer le dommage parce qu’il ne constate pas / n’a pas constaté l’infiltration.

French often avoids repeating the subject when an infinitive can do the job.

Not exactly. Constater is more formal and more objective than voir.

It often means:

• to observe
• to note
• to establish
• to ascertain

So an expert would often constater something in a report, inspection, or professional assessment.

Compare:

• voir = to see
• remarquer = to notice
• détecter = to detect
• constater = to observe/establish officially or objectively

In this sentence, constater fits well because an expert is not just casually seeing something; they are professionally identifying it.

Here, l’infiltration usually refers to water ingress, seepage, or a leak entering a building/material.

In English, infiltration can sound military or abstract, but in French it is very common in building, insurance, and damage-assessment contexts.

So depending on context, l’infiltration might mean:

• water infiltration
• water seepage
• a leak penetrating a wall, roof, or ceiling

The l’ is just the elided form of la, because infiltration begins with a vowel:

• la infiltration → l’infiltration

This is the standard French negation:

• ne ... pas = not

So:

• peut = can
• ne peut pas = cannot / cannot be able to

In careful written French, both parts are used:

• L’expert ne peut pas évaluer le dommage.

In informal spoken French, people often drop ne:

• L’expert peut pas évaluer le dommage.

But in standard writing, you should keep ne ... pas.

Because expert begins with a vowel sound, le becomes l’.

This is called elision.

So:

• le expert ❌
• l’expert ✅

The same thing happens with la:

• la infiltration ❌
• l’infiltration ✅

French does this very often before words beginning with a vowel or a mute h:

• l’homme
• l’école
• l’expert

Dommage does mean damage or harm, but learners should know that French uses a few different words depending on context.

Common options include:

• dommage = damage, harm, loss
• dégât / dégâts = physical damage, especially material damage
• dommages = damages, or damage in legal/insurance contexts

So évaluer le dommage is understandable and fairly formal/technical. In some real-life contexts, especially insurance or property damage, you might also hear:

• évaluer les dégâts
• évaluer les dommages

A native speaker might find les dégâts especially natural if we are talking about visible physical damage caused by water.

Still, le dommage is grammatically correct and works as the damage as a whole.

French often puts a cause or condition phrase at the beginning to frame the whole sentence.

So:

• Faute de constater l’infiltration, l’expert ne peut pas évaluer le dommage.

means:

• Because he has not identified the infiltration, the expert cannot assess the damage.

Starting with Faute de... makes the reason come first. It sounds formal and structured.

You could sometimes move that idea later in the sentence, but the fronted version is very natural in formal writing because it highlights the cause immediately.

By itself, faute de does not always clearly distinguish between:

• because he failed to and
• because there was no possibility/opportunity to

It mainly expresses lack or absence.

So the sentence can suggest:

• the expert did not identify the infiltration
• without identifying the infiltration, the expert cannot assess the damage

Whether that happened because of negligence, lack of evidence, or simple impossibility depends on the wider context.

That is one reason faute de can sound a little formal and neutral: it states the lack, without always explaining why that lack exists.