Unlock the full potential of your property portfolio

Beyond renovation, we analyse your property as a whole to identify opportunities that can create greater value today and in the future.

J&J's optimisation service

The hidden value in what you already own

Every property offers opportunities that often remain untapped. Renovation, energy-efficiency improvements, reconfiguration of spaces, disposal decisions or rental optimisation: our role is to identify the measures that genuinely create value.

Since 2011, we have supported owners and investors in their decision-making to optimise their property portfolios sustainably.

Deliverables

What you receive

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.

Technical and financial audit

A comprehensive analysis of your property or portfolio to identify its potential for value creation.

Optimisation strategy

Defining the most appropriate actions: renovation, transformation, energy-efficiency improvements or disposal.

Value creation

Identifying projects that can increase value: change of use, creation of units, and reconfiguration of floor areas and volumes.

Project management

Coordination of contractors and monitoring of works.

A long-term property investment vision

Support as part of an overall strategy: asset enhancement, management and optimisation.

Process

Optimise your property portfolio with J&J Invest

Phase I

Property or portfolio analysis

Renting situation, configuration, condition of the building, energy performance and planning constraints. This stage identifies where the potential lies.

Phase 2

Defining the strategy

Renovation, conversion, creation of units, energy-efficiency improvements or asset optimisation: we define a clear, prioritised plan.

Phase 3

Project implementation

Coordination with architects and engineering consultancies, planning analysis, support with permission applications where necessary, contractor selection and site supervision.

Our role is to structure and oversee the project so that it proceeds under the right conditions.

Phase 4

Renting out and management

Once the project has been completed, we can handle the renting, property management and ongoing optimisation of returns.

Your benefits

What you gain with J&J

Structure your strategy

A clear framework tailored to your profile and objectives.

Identify the right levers

Targeted analysis of value-creation opportunities within your property.

Manage the project without the burden

We coordinate all parties involved to ensure the project progresses smoothly.

Create lasting value

Renovation, conversion or repositioning: every action is designed to maximise returns.

Build a long-term vision

Optimisation, management and asset allocation integrated into an overall strategy.

Our fees

Clear fees, with no surprises

Ready to unlock your property's potential?

Start with a J&J Property Portfolio Audit: a comprehensive analysis of your current situation, opportunities to create value  and a personalised roadmap for achieving them (costs, timing, etc.)

Every stage matters

Because optimising a property involves more than renovation work alone, we have developed the "Investor Cycle": a comprehensive approach linking investment, optimisation, renting out, management and sale to create lasting additional value for your property portfolio.

The J&J ecosystem

A complete journey

InvestOptimiseRent outManageSell

Optimise

Maximise the value of your property

Who it is for

Owners and investors looking to audit and improve the performance, value or clarity of their existing property portfolios.

Our promise

To unlock the full potential of your property portfolio.

In practice

A comprehensive audit of your property portfolio, strategic recommendations, rental optimisation, a renovation plan, and asset restructuring or repositioning.

People at the heart of J&J

The Invest team

Cédric Nobels

Head of Client Strategy and Development

John de Troyer

CEO & Founder - IPI 508.063

Julie Hatert

HR & Accounting

Maria Hoogaert

Client Experience & Marketing

Nicolas Renquin

CTO

You?

Apply here

Testimonials

What our clients say about us

A highly professional and efficient team! They presented a well-structured sales file, with excellent-quality photographs, and provided outstanding follow-up with the authorities, notaries and buyer.

AG
Angela Gerome

In terms of communication, everything went extremely well. Whenever we sent an email, we received a prompt reply. Everything was very professional, and the entire process went smoothly.

CC
Charles C.

I had an excellent experience with Carole. She is incredibly kind, highly motivated and truly understanding. Throughout the process, she listened carefully to my needs and always took the time to answer my questions.

JD
Jamila Diallo

The service is highly professional while remaining warm and friendly. I was impressed by the marketing tools used and by their valuation expertise. My property was sold within a week, without conditions, for an amount 15% above the valuations provided by two competing agencies.

PM
Patrick MDF

A very good experience with J&J Properties! They were always there whenever I had questions. They are highly responsive, and everything was concluded quickly. Absolutely nothing to complain about!

CA
Chaima A

A highly professional agency providing excellent service. The sale of our property was handled quickly and efficiently, with excellent communication. Thank you again!

FB
Florence BROSSET HECKEL

Very satisfied with the work carried out by J&J Properties for the sale of our house in Brussels: they are quick, efficient and professional, and use cutting-edge technology!
John works with diligence and integrity, fundamental qualities for an estate agent.

JG
Jeanne Gilain

This is the second time in four years that I have called upon JJ Properties to find housemates for our family home.
Pauline handled my case and managed to find the right profiles (five or six people) fairly quickly. Thank you, Pauline, for your kindness and professionalism. It was very reassuring to know that my house was in your hands: you listen very carefully to the owner, and your intuition when selecting candidates enabled me on both occasions to give an enthusiastic yes to the group you presented to me in 2021, as well as to the group presented very recently in 2025. I highly recommend this agency and Pauline.

MR
MANON RAUWERS

A highly professional and, above all, personalised service. John is reassuring, ambitious and extremely available. We were delighted with the advice we received regarding the sale of our property in Brussels. I highly recommend them!

ML
Mathilde Et Diego Lambrecht

J&J Properties is an agency like few others! Dynamic, flexible and 300% professional. I would particularly like to thank Pauline Preud'homme for her professionalism and adaptability. It is a genuine pleasure to work with professionals like these.

NL
Nicolas Lamy

Everything went extremely well. The estate agent gave me excellent advice and listened very carefully to my needs. We also had excellent communication throughout the process. In addition, I was impressed by the estate agent's level of expertise: he was very knowledgeable and was able to answer all my questions.

PR
Petronille R

Thank you to Carol for her positive attitude and professionalism in marketing our property! We were more than satisfied and wholeheartedly recommend J&J!

QL
Quentin Lauwers

Hello, I highly recommend J&J Properties for their professional service, friendliness, speed and availability. I dealt with one of their agents, Vincent Annez de Taboada, whom I warmly recommend! I wish the agency and all its agents continued success :)

SM
Sarah Maréchal

After years of searching for the ideal home and dealing with just as many estate agents, we happened to meet John and his team during one of our viewings. At last, genuine professionals who are at your service and listen to you! From then on, it seemed only natural to work exclusively with them.
The results soon followed: a new home just as we wanted, in the area of our choice, and a quick sale of our first house. Thank you to the J&J Properties team.

SD
Sebastien Deketelaere

From the outset, the information provided has been clear and comprehensive, and there have been no unpleasant surprises since our collaboration began almost a year ago, I believe.
Whenever there are questions or matters to resolve, they are dealt with quickly and without unnecessary excuses, which is honestly more than appreciated!
I wholeheartedly recommend this agency!

SF
Séverine Faure - De Man

An outstanding agency with in-depth knowledge of its cases, excellent follow-up and objectivity, all delivered with tremendous courtesy and warmth! Highly recommended!

VA
Valery Autin

An agency with responsive staff who provide good advice!

LP
Louis-Antoine Pirnay
Resources

Discover our guides and tools

Guides

The smart investor's guideDownload
The guide to buying without stressDownload
Calculator

Online valuation

Discover the value of your property in just a few clicks

Estimate your property online
FAQ

View the most frequently asked questions.

There is no single ideal type of property for every investor. The right investment depends primarily on your budget, objectives, investment horizon and the level of risk you are willing to take.

A studio or flat, for example, may offer relatively straightforward management and good resale liquidity. An investment property can diversify rental income within a single investment. Other projects requiring refurbishment or optimisation may offer greater potential for creating value but demand a more active approach.

The location, purchase price, rent levels, required works, charges, financing and potential for capital appreciation are often more decisive than the type of property itself.

At J&J Invest, we can therefore search for anything from a studio or flat to an investment property or a complete property portfolio.

Our role is specifically to determine with you which type of asset best suits your strategy, rather than systematically steering you towards a predefined type of property.

The timeframe can vary considerably from one property to another and depending on the circumstances. It is important to distinguish between three main stages: preparing the sale, finding a buyer and completing the transaction.

From the moment you sign an agreement with J&J Properties, these are the timeframes you can generally expect.

  1. Preparing the administrative file: 1 to 30 days

Before a property can be marketed, several mandatory documents must be obtained. We coordinate these various procedures on your behalf.

As a guide:

  • EPC certificate: generally 1 to 7 days;
  • planning information: in Brussels, the response time can be up to 30 days;
  • electrical inspection and certificate: generally 1 to 7 days.

Some procedures can, of course, be carried out simultaneously to save time.

  1. Preparing the property for marketing: 1 to 10 days

At the same time, we prepare everything needed to present your property in the best possible light: professional photography, a virtual tour, video where appropriate, and drafting the listing.

The photography is arranged as soon as possible, taking into account the property's availability and, where this may affect the result, the weather conditions.

  1. Marketing and finding a buyer

This is the most variable stage. The location, type and condition of the property, demand and, above all, its pricing will have a significant impact on the time required to secure a satisfactory offer.

The first few weeks on the market are particularly important. A property that is accurately valued and well presented will generally have a better chance of finding a buyer quickly.

Once the offer has been accepted, the various legal and notarial stages leading up to the signing of the authentic deed must also be taken into account.

Overall, it generally takes several months from opening the file to signing the deed at the notary's office. A particularly straightforward transaction can sometimes be completed in 3 to 4 months, while a more typical case may take 5 to 8 months, or even longer in certain circumstances.

At J&J Properties, however, our aim is not to sell as quickly as possible at any price. We seek the best balance between the time spent marketing the property, the security of the transaction and the price achieved for your property.

Calculating the return on a property investment involves more than simply dividing the annual rent by the purchase price.

The gross yield provides an initial indicator, but to assess an opportunity properly, acquisition costs, any works, charges, taxation, the risk of rental voids and financing must also be taken into account.

At J&J Invest, we also place considerable importance on the return on the equity actually invested. Borrowing can create leverage and significantly alter an investment’s performance.

For a property you already own, it is also useful to calculate its current yield, based on its present market value rather than its historic purchase price. A property purchased for €200,000 15 years ago and now worth €400,000 should be analysed as €400,000 of capital tied up in your portfolio. Continuing to calculate its return solely on the €200,000 invested at the time may give the impression of an excellent return, when that capital could potentially be used more effectively in another investment.

This approach allows you to regularly ask the right question: if I had the current value of this property in cash today, would I still choose to invest it in this same asset?

Lastly, we always consider the project as a whole: rental income, gradual repayment of the borrowed capital, potential for the property to increase in value and the exit strategy.

It is the combination of these various factors that determines whether an investment is genuinely performing well and remains consistent with your wealth-management objectives.

The period from spring to autumn is generally the most favourable time to sell a property.

Longer days, more natural light and better weather help to showcase properties, particularly those with a garden, terrace or attractive outdoor spaces. Buyers are also generally more active during this period, with more viewings taking place.

However, this does not mean that you necessarily need to wait until spring to sell. A well-presented property that is priced and marketed correctly can find a buyer throughout the year. Winter may even offer certain advantages, including fewer competing properties on the market.

Ultimately, the type of property, its location, its price and the quality of its presentation often have a greater influence than the season itself.

At J&J Properties, we therefore work with you to determine the best time to launch the marketing campaign, based on your property, the market and your personal circumstances.

The cost of works should ideally be estimated before making a commitment, as it can have a significant impact on an investment’s overall profitability.

At J&J Invest, we prepare an initial estimate based on the plans, a viewing of the property and the type of renovation envisaged. Depending on the project, this estimate may be based in particular on prices per m² drawn from our experience of comparable renovations.

For larger projects or where greater precision is required, we can refine this estimate using comparative quotations and draw on our network of architects and tradespeople to obtain a more detailed cost estimate quickly.

We then include the works budget, together with a reasonable contingency allowance, in the project’s overall analysis.

The aim is to obtain the most realistic possible picture of the transaction’s total cost before purchase and to verify that it is consistent with the property’s value after renovation, the expected rents and the target return.

In Belgium, our profession is regulated by the IPI (Professional Institute of Estate Agents). The standard set by the IPI is 3% plus VAT of the final sale price.
Nevertheless, each agency remains free to set its own rates according to the quality of the services provided. At J&J, our fees vary depending on several factors, such as the price of the property, the type of contract selected, etc.  For complete transparency, we have developed a simple tool on our website that allows you to calculate the fees applicable to your situation in just two clicks. You can find the calculator here.

In accordance with standard practice in Belgium, these fees are usually payable by the seller.
 

No. You do not need to have obtained final approval from the bank before starting to work with J&J Invest.

We can begin by defining your strategy, analysing your objectives and exploring the various investment opportunities.

However, before launching an active search, it is strongly advisable to have at least a mortgage agreement in principle or an initial assessment of your borrowing capacity. This allows us to define a realistic investment budget, focus our search effectively and respond much more quickly when a good opportunity arises. A well-prepared financial application can also reassure the seller when you make an offer.

Your own funds, borrowing capacity and financing terms are an integral part of our analysis, as they can have a significant impact on the project's profitability.

The property search and financing arrangements can therefore progress in parallel, with one objective: to be ready to act quickly when an opportunity matching your strategy arises.

Yes. Through our J&J Invest service, we offer a genuine property search service tailored to your investment strategy.

We begin by defining your criteria together: budget and available equity, financing capacity, preferred areas, type of property, target return, investment horizon and wealth-management objectives.

On this basis, we actively search for opportunities that match your profile, from studios and flats to investment properties and property portfolios.

We source properties across all property portals, as well as through our network of agencies and property professionals. Thanks to J&J’s various activities and our daily presence in the market, we may also gain access to certain opportunities before or outside their conventional marketing process.

When a suitable property becomes available, we alert you promptly and analyse the opportunity with you: price, rental potential, any required works, financing and profitability.

The aim is not simply to find an available property, but to find the investment that genuinely matches your strategy.

Your property is advertised on Belgium's leading property portals, including Immoweb, Zimmo and Immovlan, as well as on the J&J Properties website and our various social media channels.

This multi-channel approach gives your property substantial visibility among prospective buyers, but our work is not simply about advertising on as many platforms as possible.

Every listing is carefully prepared to maximise its impact: professional photographs, a virtual tour, a video where appropriate, floor plans and a detailed presentation of the property. We also refine the titles, descriptions and keywords used to optimise the visibility and search ranking of online listings.

We also draw on our own network. Through our database of prospective buyers and investors, we can directly contact people whose search criteria match your property.

Depending on the type of property and target audience, we can also enhance the marketing through our social media channels, including Facebook, Instagram and LinkedIn, as well as targeted digital campaigns.

The aim is therefore not simply to be present everywhere, but to give your property the best possible exposure among the right prospective buyers.

Absolutely. Our support does not end with the acquisition of the property.

Through our Optimiser service, we can coordinate the necessary works, from straightforward refurbishment to major renovation. We assist you in defining the project, setting the budget, selecting contractors, and coordinating and monitoring the works.

Through our network of reliable contractors, architects and tradespeople, we can centralise the various stages of the project and monitor progress, costs and the proper completion of the works.

You naturally retain decision-making authority: the budget and major works are approved with you before they are carried out.

Our support can then continue with letting and managing the property. The aim is to assist you throughout the entire investment cycle, from purchase through to operation.

Yes. The way a property is presented can have a significant impact on the interest it generates among buyers.

Before putting the property on the market, we advise you on improvements that can genuinely enhance its appeal: decluttering, staging, furniture arrangement, garden maintenance, fresh paint, minor repairs or rectifying certain visible defects.

Where appropriate, we can also arrange light home staging before the photographs are taken, thanks to our network of specialist partners.

We can also use virtual home staging. Photo editing and artificial intelligence tools can, for example, be used to declutter a room virtually, remove certain items of furniture or personal belongings, replace existing furniture or virtually furnish an empty property. This allows prospective buyers to better imagine themselves in the property and reveals the potential of a space without necessarily carrying out work or moving all the furniture.

We then pay particular attention to the property's marketing presentation. A well-presented, carefully staged and professionally photographed interior creates a stronger first impression and attracts more prospective buyers.

The aim is not to have you undertake costly work before selling, but to identify the physical or virtual improvements that can genuinely enhance the property's value and make it easier to market.

A property sale generally takes place in three main stages. At J&J Properties, we support you and coordinate the entire process, from the valuation through to the signing of the authentic deed.

  1. Preparing the sale

Before marketing begins, we value your property, define the sales strategy with you and compile the necessary documentation: agency agreement, EPC certificate, planning information, electrical inspection report and any other documents required depending on the property.

At the same time, we prepare to showcase it effectively: professional photographs, a virtual tour, a video where appropriate, and preparation of the property listing.

  1. Marketing and the offer

Once the property is ready, we begin marketing it, arrange viewings and follow up with prospective buyers.

When a serious offer is made, we review it with you and also assess the prospective buyer’s financial standing, particularly their ability to secure financing. We then support you throughout the negotiations until an offer is potentially accepted.

The sale agreement is then prepared and signed, generally with the involvement of the notaries. If the purchase is subject to a financing condition precedent, it is then necessary to wait for this condition to be met within the stipulated period.

  1. The sale agreement and authentic deed

After the sale agreement has been signed, the notary carries out the various checks and legal formalities required for the sale: mortgage status, planning matters, taxation and other searches relating to the property.

Once the file is complete, a date is set for the signing of the authentic deed. The balance of the purchase price is then paid and ownership of the property is officially transferred to the buyer.

It generally takes several months between the acceptance of an offer and the authentic deed, depending on the circumstances of the transaction.

Throughout the process, J&J Properties remains your main point of contact and liaises between you, the buyer and the notaries to help ensure the transaction proceeds smoothly.

For further information, we also provide a detailed explanation of every stage of a property sale in a dedicated article on our blog.

There is no absolute minimum budget. Nevertheless, to consider a property investment on a sound basis, we generally recommend having at least €50,000 of your own funds available to invest.

J&J Invest assists a wide range of clients, from investors making their first purchase to professional investors seeking to grow or diversify their assets.

We therefore structure acquisitions ranging from studios and flats to investment properties or portfolios comprising several buildings.

Our approach remains the same regardless of the size of the project: we start with your own funds, financing capacity and objectives to identify and structure the most appropriate investments.

A property audit allows you to take a step back and assess a property or your entire portfolio to determine whether it is genuinely optimised.

In particular, we analyse the current value of the properties, rental income, profitability, costs, risks and existing financing, as well as any potential opportunities for improvement or value enhancement.

The main objective is to identify practical measures that could improve the performance of your property assets: adjusting the rent, carrying out certain works, refinancing, selling an asset that is no longer suitable, reinvesting differently or simply confirming that the current strategy is the right one.

The audit can therefore cover either a single property or a portfolio comprising several flats or buildings.

At the end of our analysis, we provide you with a clear report setting out our findings and recommendations, enabling you to make informed decisions about the next steps in your property strategy.

The notary is a public official who plays an essential role in ensuring the legal security of a property sale.

In particular, the notary verifies the title deed, the property’s mortgage status, any easements, and the various legal, planning and tax matters required for the transaction. The notary prepares or reviews the preliminary sale agreement and subsequently drafts the authentic deed of sale.

When the deed is signed, the notary also manages the financial aspect of the transaction: receiving the necessary funds, ensuring payment of the purchase price to the seller, repaying any mortgage debts, and collecting the duties and costs associated with the purchase.

The notary then completes the formalities required to make the sale enforceable against third parties, particularly by registering the deed with the relevant authority. The notary’s involvement therefore guarantees the legal security of the transaction and the transfer of ownership.

The seller and buyer may each appoint their own notary. Having two notaries does not normally increase the notarial fees for the transaction: the notaries divide these fees between themselves.

At J&J Properties, we remain in contact with the notary or notaries throughout the process to provide the necessary information and facilitate the management of the file until the authentic deed is signed.

When selling a property, it is important to compile a complete administrative and technical file. This ensures compliance with legal obligations, reassures prospective buyers and prevents a missing document from delaying the sale.

Depending on the type of property, its location and the Region in which it is situated, the main documents required include:

  • the title deed;
  • the EPC (Energy Performance Certificate);
  • the electrical installation inspection report;
  • the planning and cadastral information;
  • soil-related information or certificates, where required;
  • documents relating to any oil tank;
  • permits, plans and documents relating to any works or alterations carried out at the property;
  • the asbestos certificate or inventory, where required;
  • any other specific certificates or attestations that may be required depending on the property and its location.

If you are selling a flat or a jointly owned property, an additional file must also be obtained from the managing agent. This includes the basic deed and the co-ownership regulations, the minutes of the latest general meetings, service charge statements, the co-ownership accounts, the status of the reserve fund and working capital fund, as well as information relating to any works that have been approved or are under consideration and any debts owed by the co-ownership.

If the property is currently let, you will also need to gather the tenancy agreement, the inventory of fixtures, information relating to the rental deposit and any other relevant documents concerning the current tenancy.

The exact list may therefore vary considerably from one property to another.

When you entrust the sale of your property to J&J Properties, we identify the necessary documents from the outset and assist you in gathering them. We can also handle some of the formalities with the relevant authorities, the managing agent and the various parties involved on your behalf.

Preparing a complete file in advance helps reassure buyers, anticipate any potential difficulties and ensure that the sale proceeds smoothly.

Yes. Where required by the project, we can assist you with the various administrative procedures, particularly in relation to planning matters: permits, regularisation, change of use or major renovation.

For tax, legal or accounting matters, we work with property specialists to whom we can refer you. The aim is to provide comprehensive support throughout the project, while bringing in the appropriate specialist whenever a matter falls outside our area of expertise.

Of course. Many foreign investors and expatriates invest in Belgian property without living in the country.

J&J Invest can assist you remotely throughout the process: defining your strategy, searching for and analysing opportunities, viewings, acquisition, coordination of the various parties involved and, if necessary, supervision of works. Meetings can easily be arranged by video call and documents shared online.

Our teams can therefore act as your local representative and assist with numerous procedures, saving you from having to travel to Belgium each time.

Once the property has been acquired, J&J Properties and J&J Management can also handle its letting and day-to-day management.

However, the tax and legal position and financing options may vary depending on your country of residence and personal circumstances. Where necessary, we can refer you to specialists to ensure that your investment is structured correctly.

The aim is to enable you to invest in and manage a property portfolio in Belgium with the same visibility and support as if you were there in person.