About us


With a concern for the objectives of process digitalisation in the construction sector, TREEX investigates the possibilities of creating digital profiles for the buildings audited - digital twin - which would integrate dozens of photos taken during the audit of the building, into a three dimensional plan of the building. 

Treex is an independent consultancy bureau specialising in undertaking technical audits of buildings both in terms of their construction and of their technical installations. Technical due diligence are principally carried out on behalf of investors considering the sale, conservation or acquisition of a real estate asset, which may be of any type: offices, residential, retail, warehousing, hotel… We advise local and international investors: large landlords, investment funds, banks and insurance companies. 

Treex is active in Belgium and Luxembourg. Our extensive knowledge and long experience of these markets enables us to easily benchmark the building being audited with market standards. 

Following a physical audit of the condition of a building, we propose solutions for bringing it into line with accepted norms and market standards in order to remedy problems observed.

These recommendations take the objectives of the client into account, whether they be in terms of the ROI or of the occupation of the building, and which would require an investment plan. We pay a great deal of attention to the destination of the building if it is to change in function or, for example, is to be partitioned into several distinct units. 

During an audit we identify and evaluate in detail the cost of the works recommended, ensuring that this is realistic in view of the acquisition price for the building, and we distinguish between those works which are indispensable and priority, and those which are secondary in importance. We establish a time schedule for the investments in view of the state of dilapidation of the building and of its equipment. We indicate specific additional studies which should also be carried out (ground pollution, presence of asbestos, conformity of the electrical installations, lead pipe-work, water infiltration… etc.). 


Thomas Maskens founded Treex in 2013. Prior to that Thomas had worked for seven years as Head of Project Management within real estate management company Sogesmaint-CBRE. Here he acquired knowledge of the sector and a spirit of synthesis enabling him to reconcile technical constraints with the economic necessities of the client. 

In order that he can carry out relevant technical audits with high added value, Thomas Maskens today manages a small and bonded team which, according to the nature of the project, is reinforced by external auditors. All share the same values of neutrality, efficiency and quality. 

I.              Technical due diligence

The audit reports we draw up include a general description of the building and of its condition at the time of carrying out the audit. Depending on individual cases and on necessity, our auditors will examine all or some of these elements:

The observations are accompanied by numerous photos taken on site during the inspection. We also make recommendations relative to cleansing and maintenance works, to modernisation and renovation which, in the light of our analysis, may be needed in the medium and long terms. Certain of these recommendations may involve carrying out works which will increase the value of the building for the investor. For example in terms of respect of environmental concerns.

II.            Project management 

Following technical audit, Treex can implement and manage the work project. This implies an in-depth analysis of the project including the legal constraints –in particular those involving urban planning – and those allied to the environment. We are able to coordinate those studies still to be carried out in order that the project can be put into work. These recommendations take the objectives of the client into account, whether they be in terms of the ROI or of the occupation of the building.

We act as project manager representative of the owner and take charge of internal coordination with the project team and external coordination with the various companies taking part in the project (demolition, construction, renovation, rehabilitation,... ). We also ensure the coordination of those studies still to be carried out in order that the project can be put into work.

Depending on individual cases and on the requests of our client, our project management will include the drawing up of a provisional time schedule and budget and the management of these during the works. We can take charge of drawing up the specification in order to undertake the necessary calls for tender and then to select the various companies to be part of the project realisation. 

Once the renovation project is underway and during the whole of its execution, we take part in onsite meetings in order to check that the works are being carried out correctly. Regular reports are submitted to the client with proposals for any arbitration required in order that the schedule and the budget are adhered to.  We can also take charge of verifying and approving invoices submitted to the client by service and other suppliers.