Advice about Dossier Diagnostic Technique:

Brief description:

DDT reports signal specific problems. They do not report on the consequences of these problems, how the problems could be resolved, or what the technical condition is of the property. It can be very difficult to interpret the contents of these reports. Although this may be the case, the information in these reports could be very important and ignoring any of the reported issues could cost you a lot of money.

Always ask the seller for a copy of the DDT. Do not make a purchase decision before you fully understand what the possible consequences are of what is reported.

FPS will analyse the reports and clarify the contents. Together with your designated expert you can decide what steps must be taken to assess the consequences of any issues that may have been reported. We will combine this investigation with a survey, wherever possible.

Detailed description

Every French property that is being sold must be inspected for the presence of termites, asbestos and/or lead, the condition of the electrical wiring and the gas installation(s), the energy efficiency of the property, the condition of the septic tank, etc.  It is the owner’s responsibility to have these obligatory inspections carried out and pay for these.

The collation of these inspection reports are collectively known as the Dossier de Diagnostic Technique (DDT).

The DDT is not just a formality. On the contrary, the DDT may show for example that an electrical installation is sub-standard and fails to meet current safety regulations.  The information about energy consumption levels is useful as it gives you an indication of what it will cost to heat the property. It is therefore important to fully understand the DDT.

At some time during the purchase process you will receive a copy of the DDT. The reports can be difficult to read and you could be tempted to accept them for what they are. In most cases ignoring these reports will not have serious consequences. You could however make a costly mistake.


Why don’t you ask FPS to explain the contents of the diagnostics reports to you? After having analysed the reports, the expert will provide you with his opinion about the seriousness and possible consequences of the reported problems.

In exceptional circumstances it may be necessary to have a possible problem examined in more detail by an expert. FPS can send a surveyor to the property to investigate the problem, determine the consequences, suggest the required remedial actions (if at all possible), and give an indication of the financial consequences.

As the name Dossier de Diagnostic Technique already suggests, the report only contains a diagnosis. The DDT inspector does not give any information about the significance of a problem, if and how that problem can be resolved, or about the technical condition of the property. It is important to know that the DDT does not replace the technical survey.

Only a professional who has a legal obligation to tell the truth can help you with your purchase decision. FPS surveyors have that obligation and provide you with information that is truly objective and independent. Asking an estate agent or a local builder to interpret the DDT is not recommended. They often cannot be held accountable when they inform you that what is reported in the DDT is trivial and you discover later that the problems are serious.

Please note that, from 1 January 2011, every property that is being advertised – by an estate agent or the owner – must have been tested for energy efficiency (DPE). The DPE is payable by the seller.