
Unlock the full potential of your property portfolio
A property can often generate greater value.
We identify and activate the right optimisation levers: renovation, transformation, energy improvement or arbitrage.
The optimisation service by J&J
Many properties have untapped potential: undervalued rents, renovation potential, space configuration to optimise, insufficient energy performance, or the sale of certain assets to reinvest.
At J&J, we analyse your property or portfolio, identify the value creation levers and support you in implementing them.
What you get
By choosing J&J, you are not simply engaging an agency:
you benefit from structured support to analyse, optimise and enhance the value of your property portfolio.

A comprehensive analysis of your property or portfolio to identify value creation potential.
Defining the most relevant actions: renovation, transformation, energy improvement or arbitrage.
Identifying projects to increase value: change of use, creation of units, reconfiguration of spaces and volumes.
Coordination of stakeholders and works monitoring.
Support integrated into an overarching strategy: value enhancement, management and asset arbitrage.

What our clients say about us
How to optimise your property
Property or portfolio analysis
Rental situation, configuration, building condition, energy performance, planning constraints. This stage identifies where the potential lies.

Strategy definition
Renovation, transformation, creation of units, energy improvement or arbitrage: we define a clear and prioritised plan.

Project implementation
Coordination with architects and consultancies, planning analysis, planning permit support where required, contractor selection, site monitoring.
Our role is to structure and oversee the project so that it proceeds smoothly.

Letting and management
Once the project is complete, we handle the letting, rental management and continuous yield optimisation.





Two approaches to enhancing a property's value
Classic approach
The property is kept as it is
Works are carried out on an ad hoc basis
The planning potential is rarely assessed
Decisions are made on a case-by-case basis
Value enhancement remains limited
The project is managed alone
With J&J support
The property's potential is analysed
A renovation or transformation project is structured
The planning potential and permit possibilities are assessed
A strategy is defined upfront
Value creation is actively pursued
The project is coordinated with all stakeholders
Choose J&J if you wish to:
Structure your strategy
A clear framework tailored to your profile and objectives.
Identify the right levers
Targeted analysis of value creation opportunities in your property.
Drive the project without the burden
We coordinate all stakeholders so that the project moves forward without friction.
Create lasting value
Renovation, transformation or repositioning: every action is designed to maximise returns.
Build a long-term vision
Optimisation, management and arbitrage integrated into an overarching strategy.
See our references

Ready to unlock the potential of your property?
Start with an audit of your situation with a J&J expert.
A complete journey
Invest
Search, identify and acquire the best opportunities
For whom
Investors, entrepreneurs and wealth-minded profiles who wish to grow their property portfolio without managing the operational complexity.
Our promise
Build a coherent and high-performing property investment strategy across the entire property cycle.
In practice
Targeted search, financial analysis, project structuring, acquisition support, value enhancement and integrated exit strategy.
Optimise
Maximise the value of your property
For whom
Owners and investors who wish to audit, improve the performance, value or clarity of their existing portfolio.
Our promise
Unlock the full potential of your property portfolio.
In practice
Global audit of your property portfolio, strategic recommendations, rental optimisation, renovation plan, restructuring or repositioning of assets.
Rent
Find the best tenants
For whom
Owners wishing to let quickly and efficiently whilst securing an optimal rental income.
Our promise
Maximise and secure your rental income.
In practice
Rental valuation, property presentation, targeted marketing, rigorous tenant selection and lease management.
Manage
Simplify day-to-day management
For whom
Owners who wish to hand over the day-to-day management of their properties with complete confidence.
Our promise
Serene, transparent and professional management.
In practice
Administrative, financial and technical management. Tenant monitoring, coordination of interventions and clear reporting.
Sell
Achieve the best return on your investment
For whom
Owners and investors looking to arbitrate, dispose of or restructure their portfolio.
Our promise
Sell at the right time, with a clear and well-considered strategy.
In practice
Timing analysis, property valuation, sales strategy, and support through to and after the signing of the deed.
People at the heart of J&J
Explore our guides and tools

Online valuation
Discover the value of your property in just a few clicks
Browse the most frequently asked questions.
In Belgium, residential properties (city-centre flats, suburban houses) remain attractive for their stable rental demand. Student residences and co-living properties also offer high yields. Profitability depends above all on location, property quality and the rental amount relative to the purchase price. Dynamic areas (Brussels, Liège, Namur, etc.) or well-connected neighbourhoods with strong rental demand are often recommended.
You no longer wish to chase files, tradespeople, banks or tenants.
On average, a property sale in Belgium takes several months. According to recent studies, the total timeframe (from listing to signing at the notary's office) is approximately 3 to 8 months. A 'fast-track scenario' (cash buyer) can complete the sale in 3–4 months, whilst a standard sale (with a conditional mortgage) typically takes 5–8 months. These timeframes include preparation of the file (EPC certificates, electrical inspection, etc.), the viewing and offer phase, and notarial formalities.
Divide the gross annual rent by the purchase price and multiply by 100 to obtain a percentage. For example, a property worth €200,000 rented at €1,000/month yields approximately 6% gross yield. In practice, this is also compared against the 'reference rents' for the region (official tools in Brussels/Wallonia) to set a competitive rental level.
You refuse to let chance or poor advice jeopardise millions of euros of assets.
Specialists agree that spring and autumn are the most favourable seasons for a sale. In spring, the light and pleasant weather attract more motivated buyers, and viewings and transactions peak. Autumn, being less competitive (fewer new properties on the market), is also favourable. Summer and winter can be slower, but a well-presented property (a blooming garden in summer, a warm interior in winter) helps to convince buyers.
We produce estimates based on plans or comparative quotes. In Belgium, a per-square-metre rate is generally applied (depending on the type of work). Thanks to our network of architects and tradespeople, we can quickly provide a detailed breakdown of any planned renovation costs.
Our commissions are free and negotiable. In Belgium, they generally range between 2% and 5% (excl. VAT) of the sale price. In accordance with Belgian practice, these fees are typically borne by the seller. The details (exact rate, VAT, etc.) are set out in the sale mandate we sign with you.
It is advisable to obtain at least a bank pre-approval (letter of intent to lend) before beginning your search. This reassures sellers and focuses your search on a realistic price range. That said, you may explore the market first and confirm your financing at a later stage.
You can start investing from as little as €100,000–150,000 (e.g. a studio flat in the city). The main constraint is borrowing capacity: as a rule, you need at least 20–30% of your own funds to cover the deposit and associated costs (6–7% of the purchase price). We help you tailor the project to your budget and your objectives (expected rental income, capital gain, etc.).
You want your investments to have a lasting impact, aligned with today's environmental and societal challenges.
Yes: we offer a 'property finder' service. We define your criteria together (areas, property type, target yield) and alert you promptly as soon as a matching property becomes available. This includes sourcing across all portals and through our network of agencies, even in areas where you do not reside.
Your property will be listed on all the major Belgian property portals (such as Immoweb, Zimmo, Vlan, etc.), on our own website and on our social media channels. This maximises visibility. We also ensure the use of relevant keywords (e.g. 'apartment Brussels for sale') to optimise SEO, so that targeted buyers can find your listing online.
You wish to benefit from privileged access to off-market properties and opportunities reserved for our clients.
Absolutely. Our management team can coordinate works (from minor repairs to major renovations) through our network of reliable Belgian contractors. For any job exceeding a certain amount (for example €150), we obtain your written approval before proceeding.
Yes. We work with home staging partners and provide presentation advice (decluttering, styling, garden upkeep). A well-presented and well-photographed interior attracts more buyers. We can arrange a light home staging session before the photo shoot, or simply guide you on small improvements (fresh paint, minor repairs, etc.) that enhance the property's appeal.
Yes. Our rental management services cover tenant sourcing, lease signing, rent collection and day-to-day administration. Standard management fees range between 5% and 10% of rents received. We also prepare service charge statements, ensure compliance with tenant obligations and intervene in the event of a dispute (unpaid rent, damage, etc.).
The sale proceeds in three key stages. First, prior to listing, we value the property and prepare the file (mandate, mandatory surveys). Then, during the marketing phase, we manage advertising and viewings. When we receive a serious offer, we assess its soundness (credit capacity) and organise the signing of the preliminary sale agreement (often at the notary's office or at the agency). After any mortgage condition is lifted (4–6 weeks if the buyer requires finance), the notary carries out the legal formalities (planning checks, mortgages, etc.) over 1–2 months before setting the date for final signing. At that point, the buyer pays the price and you sign the authentic deed. This process is described in detail on our blog.
There is no strict lower limit, but a profitable investment typically requires several tens of thousands of euros. For instance, a small flat in Brussels can be found from around €150,000–200,000. We can advise you on opportunities suited to your budget through our valuation tools and market analyses.
The audit is a comprehensive review of your existing properties: rental income, taxation, risks and profitability. It is particularly useful if you own several properties or are considering a change of strategy (sale of certain properties, renegotiation of loans, etc.). The cost varies according to the complexity of the file (generally a fixed fee). We provide a clear report to help you optimise your portfolio.
The notary is an indispensable public officer: Belgian law requires them to draft the authentic deed of sale in order to make the transaction enforceable against all parties. The notary verifies the title to the property and any easements, drafts the final deed, collects the price and the registration duties, and officially records the sale. Through the notary, the buyer becomes the legal owner and the transaction is secured legally. In short, the notary guarantees the validity of the sale and ensures the transfer of ownership (mortgage registration).
A complete file must be compiled in order to inspire confidence. Mandatory documents include:
- EPC Certificate (Energy Performance Certificate): required before the listing can be published
- Electrical inspection certificate (compliance report)
- Fuel oil tank certificate (if you have a tank >3,000 L)
- Planning information: land registry extract, any planning permits, regularisations to be carried out
- Asbestos-free certificate (for older buildings, regulations currently in force)
- Co-ownership documents (minutes of general meetings, reserve fund, service charge statement) if selling a flat
- Sewerage connection (in certain municipalities) and soil certificate for specific plots of land
In short, a clear file (EPC, title deed, surveys, co-ownership information, etc.) reassures the buyer and speeds up the sale.
We help you gather all these documents in advance.
Yes. We can assist you with planning permission procedures if your project requires it (extension, major renovation), and guide you on regional tax incentives (energy grants, depreciation allowances, etc.). We work alongside legal and accounting professionals specialising in property.
Of course. Many foreign investors are active in Belgium. We facilitate remote communication (video calls, online documents) and a local representative can act on your behalf for viewings and formalities. Belgian regulations do not require residency in order to buy or rent a property.
















