Diagnostics surveyor, pre-purchase expert, architect or address report: which help for which need?
The diagnostics surveyor carries out the compulsory reports in the diagnostics file, paid for by the seller. A building expert you instruct examines the condition of the house before purchase. An architect designs a works project and is compulsory for a permit above 150 m² of floor area. An address report reads the public registers: planning, hazards, neighbouring permits, prices. None replaces another.
The roles at a glance
| Who | For what | Paid by | Cost |
|---|---|---|---|
| Diagnostics surveyor | The reports in the DDT | The seller | Unregulated prices, on quotation |
| Building expert | The condition of the house before purchase | The buyer | On quotation |
| Architect | A works project, the permit file | The client | On quotation |
| Address report | The address’s public registers | The buyer | €29 incl. VAT for ScanAdresse |
Before you sign, other checks matter too, such as what to check before buying and who provides what before buying. For one address, the free ScanAdresse preview shows for free what the registers say.
The diagnostics surveyor
The diagnostics surveyor produces the reports the seller must attach to the compromis: DPE, lead, asbestos, electricity, gas, termites and, where needed, the energy audit. The law requires them to prove their competence, to be insured and to have no link with the owner or agent that could affect their impartiality (art. L271-6 of the Construction and Housing Code); a public directory lets you check their competence. Prices are not regulated. Their role is limited to these reports: they give no opinion on the structure or the price.
What the diagnostics file does not say
The pre-purchase building expert
A building expert you choose and pay visits the house, with you or alone, and describes what they observe: cracks, damp, frame, roof, installations. It is not a legal requirement, and the title is not regulated in the same way as the diagnostics surveyor’s: ask for their qualifications, their insurance and a precise quotation of what will be inspected and delivered. The right moment is before the compromis or during the cooling-off period.
The architect
The architect comes in when you have a project: an extension, an extra storey, a reconfiguration. They design the project, prepare the permit file and can supervise the works. An individual must use one for a building permit above 150 m² of floor area, or when an extension takes the house beyond that threshold; never for a simple works declaration. Before buying, a first visit can tell you whether your idea is realistic; the decision on a permit always rests with the mairie.
Extending a house: declaration or permit
The address report
An address report does not visit the house: it reads the public registers. ScanAdresse brings together for one address the parcel, the PLU zone and regulations with their articles, the public easements, the Géorisques hazards, polluted soils, airport noise, permits in the cadastral section, the DPE and nearby sales, with found, not found or source unreachable for each register; €29 including VAT, free preview. It complements the work of building professionals without replacing it.
Which help for which need
- You want to know whether the reports are complete: reread the diagnostics file; the notary checks the list.
- You fear a hidden defect, a crack or damp: a building expert.
- You want to extend or convert: an architect, and the mairie for the rules.
- You want to know the rules, the hazards and what is changing nearby: the public registers, directly or brought together in an address report.
- You have a legal question about the compromis: the notary or a lawyer.
DPE F or G: energy-inefficient homes
Frequently asked questions
Can the buyer choose the diagnostics surveyor?
No, the seller orders and pays for the reports. You can, however, instruct your own building expert.
How much does a pre-purchase expert cost?
There is no regulated fee: the price depends on the house and the scope. Ask for several detailed quotations.
Does an address report say whether I can extend?
It shows the PLU rules that apply to the parcel, article by article. Only the mairie decides on a permission, on a submitted application.
Sources
- Service-public: property diagnostics to provide
- Service-public: finding a diagnostics surveyor
- Service-public: when to use an architect
- Construction and Housing Code, art. L271-4 and L271-6
ScanAdresse is a private service by SRI Group BV (VAT BE1037052239), not connected to any public authority: it brings together public data, with the source and date of every item.
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