Architecture and heritage reconciling past and future

A square-plan farmhouse, a manor house, an old presbytery: these buildings have a value that goes beyond their floor area. To make them comfortable, energy efficient and compliant, you need to take into account a regulatory framework that has changed considerably over the past two years. Here is what we see on the ground, at STARC and Optibim, and what you need to know before drawing the first line.

Identifying the exact status of your building

It all starts with a simple question: is your property protected, and under what status. The answer determines the procedure, the timeframes and the possible grants.

In Wallonia, several levels coexist:

• The listed building, with the strictest constraints but also the most substantial grants.
• The safeguard list (liste de sauvegarde), for urgent situations. According to the Walloon Heritage Agency (AWaP), this is a transitional measure lasting 6 months, protecting the threatened property during that period since almost all the effects of listing apply to it.
• The protection zone around a listed building. Its effects are mainly procedural and affect the issuing of urban planning certificate no. 2, planning permission and subdivision permits.
• The regional inventory. Inclusion of a building in the inventory can either be simple (inventoried building) or flagged with a marker known as a pastille (flagged building). A pastille indicates a particular heritage value identified for that building.

In Brussels, the CoBAT (the Brussels Town Planning Code, also known as BWRO) likewise distinguishes between listed buildings, those on the safeguard list and those included in the inventory. The Cultural Heritage Department of urban.brussels is the relevant point of contact.

The first pitfall to avoid: relying on the seller's or neighbour's memory. Check the status on the regional geoportals or with the local council's planning department, ideally before signing any preliminary agreement.

In Wallonia, the CoPat has changed the order of the process

In force since 1 June 2024, the new Walloon Heritage Code (CoPat) clarifies, structures and harmonises the legal provisions. For a listed building, the major novelty is the heritage permit. The Union des Villes et Communes de Wallonie describes it as an essential prerequisite before submitting a planning application for a listed building.

In practice, this means:

• Heritage meetings held in advance. AWaP handles and monitors these meetings, in which the Royal Commission for Monuments, Sites and Excavations is involved.
• Almost no exemptions. There is only one exception to the requirement for a heritage permit: maintenance works without a grant application.
• A validity period to factor into your schedule: the permit is valid for 5 years for works, and 2 years for activities and events.
• For recurring maintenance, the operational heritage plan, treated as a heritage permit with an extended validity of up to 10 years.

On the funding side, AWaP points out that listed buildings can benefit from joint grants from Wallonia, the province and the municipality for restoration works. Two practical rules have a real impact on scheduling: combined grants cannot exceed 100% of the total cost of the works, and works may only start once the signed decree has been received.

A point to watch this year: following the Walloon Government's decision on the 2026 budget, it will not be possible to submit a grant application in 2026 for works on a flagged building. If your project depends on this, it is better to spread it over time than to start the works too early.

In Brussels, clear rates and strict conditions

For listed buildings, urban.brussels states that the rate is 80% for public beneficiaries, while for private beneficiaries the base rates are 40% or 50% for works on the external envelope, with possible increases depending on income, the property's situation or the type of works. In return, the beneficiary agrees to inspection visits and must provide, once the works are complete, a restoration report describing the most significant interventions.

For unlisted features visible from the street (sgraffito decoration, ironwork, façade joinery), the small heritage grant (prime petit patrimoine) is often underused. No financial support is granted for maintenance works or works already carried out. Good news for co-ownerships: the ceilings (€10,000 or €15,000 per 5-year period) now apply per property unit rather than per building.

Energy performance and heritage, no automatic exemption

This is the point that causes the most confusion. Many owners believe that a protected building is exempt from EPB (energy performance) requirements. That is not correct.

In Wallonia, SPW Énergie states that for places of worship and buildings that are listed or included in the heritage inventory, the exemption is not granted automatically. It must be justified in the EPB declaration submitted with the planning application, and an exemption cannot be regularised retrospectively. Another important nuance highlighted by Embuild Wallonie: if only the façades are listed, all work on the other elements (roof, floor, window frames, and so on) must still comply with the requirements.

In Brussels, Bruxelles Environnement (Leefmilieu Brussel) specifies that it is the issuing authority that decides whether to impose a heritage EPB derogation. The framework is set out in the order of 6 June 2024 determining the criteria and procedure for derogation from EPB requirements and decarbonisation measures.

At European level, Directive 2024/1275 provides that a Region may set aside certain standards for protected buildings, insofar as applying them would unacceptably alter their character or appearance. Its transposition is ongoing, which is why it is worth following the regional texts closely.

On a technical level, a derogation does not excuse poor workmanship. Our engineers at Optibim pay particular attention to a few points:

• Internal insulation of thick brick or stone walls, which can shift the dew point and put embedded beam ends at risk. A hygrothermal study is often required.
• Choosing vapour-permeable materials (lime, wood fibre, hemp) rather than airtight systems.
• Airtightness, measured with a blower door test, which often allows significant gains without touching the façades.
• The discreet routing of services (ventilation, heating, electricity) through spaces that were never designed for them.

Our method, from survey to site

On an old building, the costliest mistake is designing from approximate drawings. Here is how we work:

1. Precise survey of the existing building by BimBot: 3D scanning, drone footage for the roofs and 360° photography. Deformations, out-of-plumb walls and actual thicknesses become apparent from the outset.
2. Cross-diagnosis: stability of floors and roof structures, damp, condition of the masonry, energy potential.
3. Preparation for heritage meetings with clear documents distinguishing what is retained, restored or altered.
4. EPB assessment: justifying an exemption or derogation only where it is warranted, with maximum performance elsewhere.
5. Realistic scheduling with Chronoplan, factoring in permit and grant decree timeframes.

The pitfalls we come across most often: works starting before the grant decree is issued, internal insulation installed without a study, window frames replaced without checking the façade's status, or a budget drawn up without allowing for preliminary studies.

Talking to the right team from the start

You own an old building, listed or not, and you have a project to renovate, convert or turn it into housing. The teams at STARC and Optibim can assess its status, carry out the survey and support you through the process with AWaP, urban.brussels and local councils. Contact us in Gembloux for an initial discussion about your project.

Frédéric Odent, Director