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What to know before starting

📐 Topic5 min read

What you will learn The difference between transaction surveys and works surveys, what each covers, why one does not replace the other, and the order in which to commission them.

A property sold comes with documents. Those documents do not suffice to prepare a project, and confusing them is the commonest error at the start of a renovation.

Two families of survey

Transaction surveys Works surveys
Purpose inform the purchaser prepare and make the works safe
Trigger sale, gift, transfer nature of the works planned
Method generally non-destructive often destructive
Scope what is accessible and visible what will actually be touched

The first are imposed by regional rules. They accompany transfer of ownership.

The second answer a technical need, and some are imposed by employment rules where workers are involved.

A sale document therefore does not dispense with a works survey, developed in the article on asbestos and its identification.

Surveys by region

A Belgian characteristic to absorb from the outset. The compulsory surveys differ by region.

Obligations differ between regions, including for documents on the same subject.

Asbestos is the clearest example. One region requires a certificate on transfer of ownership; the other two require nothing to date, while considering changes.

Energy assessments exist everywhere but in forms, names and requirements specific to each region, covered in the article on energy assessments by region.

The practical rule: check the list applicable to the region of the property, rather than transposing experience from a project elsewhere.

What surveys bring to the project

Three direct contributions, beyond the administrative obligation. They bear on pricing, the calendar and negotiation.

They reduce budget contingency, turning unknowns into quantifiable data, connecting with the article on pricing with a contingency.

They govern the method of work. The presence of certain materials imposes procedures and specific participants, with effects on the programme.

They serve as a reference in disagreement. A documented condition before works allows what pre-existed to be distinguished from what results from the project.

What they do not cover

Four limits, and ignoring them leads to making them say more than they do. A survey records a state at a date, within a defined scope.

What is not accessible. Most transaction surveys are non-destructive and do not see what is enclosed within walls.

What post-dates a pivotal date. Some obligations cover only buildings predating a given year, and more recent parts are excluded.

Structural condition. No common regulatory survey pronounces on capacity or the condition of loadbearing elements, covered in the article on structural unknowns.

Suitability for the brief. A survey describes a condition; it does not say whether what is planned is achievable.

The order in which to commission them

Four steps, and the order saves time and money. They take place before firms are consulted.

Gather what already exists. Documents handed over on acquisition, certificates still valid, original drawings.

Check the applicable obligations, by region and by nature of the project.

Add the surveys needed for the works, based on what is actually planned.

Commission structural investigation last, once the brief is defined enough to know where to look.

Investigating before having a brief means investigating in the wrong place, which costs without reducing risk.

The articles in this branch

The article on asbestos and its identification covers regional obligations and the difference between certificate and inventory. The obligations are set out there.

The article on energy assessments by region covers certificates and audits. The regimes are compared there.

The article on the state of the electrical installation covers inspection and its validity. The inspection is explained there.

The article on the preliminary file gives an eight-document method. The documents to gather are listed there.

This article reflects the position of the rules at the date of checking and serves professional orientation. It does not replace technical advice or consultation of the regional texts.

Frequently asked questions

The compulsory surveys, the useful investigations, the permit check and assembling the preliminary file. The order of those four steps saves time and money.

For pricing, planning and negotiating, because they turn an unknown into data. That is their main contribution to a project.

They record a state at a date and within a defined scope, and nothing more. Making them say more is a frequent error.

No, they differ by region, which is a Belgian characteristic to absorb from the outset. The applicable list is checked at source.

Explore the articles in this guide

Renovating an existing building in Belgium