Updated financial estimate

Hello @reeflings,

Today Julien, Richard and I had an online meeting with the architects to discuss the updated financial estimate that they have prepared for us (internal link to the recording). With the price of steel having gone x6 and that of cement x3, this was dearly needed. Here’s a short report about the key points (@Julien and @RichardB feel free to complement it!).

1. The updated file

The update file is saved in Team Finance > Estimations and scenarios (internal link). It is an Excel file, so you can play around with the numbers yourself. Please do so in a copy of the file though, and not in the original!

2. Key numbers
  • The price of the square meter in the estimate equals 4167 euro. This includes finishings (750 euro per m² net), VAT and notary costs, but not a parking spot (30.000 euro), storage space in the basement (1350 euro per m²) and a terrace (1500 euro per m²). The finishings of the common spaces are also not included (see cells D28 and D29).

  • This price is calculated based on 25 units of 90 m² net (= 2700 m² in total gros) + 270 m² of common spaces (the default is 10%).

  • An example is included for a unit of 90 m², which would cost 375.000 euro excluding any extras (parking, storage space, terrace).

3. Notes about the calculations
  • The price per m² is roughly calculated by dividing the total budget (minus the extras to be purchased, like parkings), which is 11 million euro, by the total gross private square meters (2700 in the estimate).

  • The calculations are made based on 21% VAT, to avoid unpleasant surprises.

  • The calculations are made without including any possible subsidies.

  • The estimates do include a lot of future-proofing stuff already: capturing rainwater, solar panels, heat pump etc. Taking this one step further (e.g. getting a battery) would not increase our budget by much.

  • The calculations seem highly sensitive to the total surface of our units together. If I try 25 units of 70 m² net (which seems more realistic for the moment), the price goes up to 4430 euro per m². Likewise, based on an average size of 110 m², the price goes down to 4000 euro per m².

  • Changing the total surface of our units does not affect the price in relative terms. In both estimates (70 and 90 m² on average), the price of the common spaces is on average 200 euro per m² (i.e. include in the 4000 something).


@Lee nice minutes

The price for buyingg a site and the price of building are like communicating vessels. When one goes down, the other goes up making less difference in total prices per apartment.

The finishing of the common spaces as stairs, lifts, … is included.
I gues some summary finisching of common spaces as shared rooms, cowork space, atelier, laundry, … is also included.

It’s a detail, but I don’t think it is. You can see it in cell A29 “finitions hors sol”, where they multiply cell C9 (25 units, net) with 750 euro, compared to cell A29 “casco hors sol”, where they mutliply cell C8 (cost of the casco) with cell C14 (all units + technical space + common spaces).

Thanks a lot Lie for this! A couple of questions:

There is no link :slight_smile:

if it is indeed not included, any idea what the extra cost would amount to for every household?

In this estimate, it is for 90m2 brut right? (D58 is 90* the estimate, which is given by m2 brut). Which would mean it is for 72m2 net.
Also, can we consider a parking spot as extra? Are we confident that all communes do not make it compulsory to have one per appartments?

I added it now

I have no idea, but I can do a back-of-the-envelope calculation: let’s take 200 m² at a price of 500 euro per square meter (which is way more than it will be in my view). That makes 100.000 euro, which would come down to 4000 euro per household, if all units were the same size


The parking spots are indeed a point of uncertainty, but I wouldn’t worry too much about it. The key concern that should be on Team Finance’s radar is whether we’ll manage to sell the spots before we start building (because who else is going to front the money), and more importantly what will happen in the worst case scenario where the market price of a parking spot is lower than the building cost. In that case I’m afraid we’ll have to share that financial burden, which will hopefully be not much more than 65.000 euro.


Julien had a detailed conversation with the architects about the updated financial estimates. It can be found in the common mailbox, dated 4 July 2023. Here are the essentials that we want to retain:

  • There is a misunderstanding about whether the finishings of the common spaces are included yes or no. I believe that this is because there is a misunderstanding about the term “common spaces”. When the architects say that the cost of the finishings of the common spaces is included, they refer to stair cases, hallways etc. From the excel sheet however it can be seen that finishings of the common spaces in the sense of common living room, guest room etc is not included. As said above this should not make a big difference though.

  • The prices of the options (parking, storage space in the basement, terraces) need to be set by the group. The numbers in the architects’ file are just an indication. The prices in the estimation include VAT and fees etc. The probable reason for this - which is something my dad noted - is for example that the revenues from the options in the basement (about 700k) does not match the cost (about 900k). I believe that this because there is a certain amount of costs related to the underground that need to be shared by all, but I guess we’ll discuss the details of this at a later stage.

  • The price per m² is for the net surface, because this is what is used by the notary, surveyor (“géometre”) etc.

  • VAT 6%:

  • “Taxe sur la batisse” (stedenbouwkundige lasten): this is a communal tax that is added on top, and is different for every commune (but not all communes have them). The architects gave us the link for the tax sur la batisse in Jette: it’s a couple of euros per square meter for renovated buildings and around 250 euro / m² for newly built. This matches out with the story they told us, where they said that they divided the total cost equally among them, in solidarity with those who bought the units that were newly built: see Visit to The Spiegel - #3 by JolanWuyts

The next steps I believe will be a new, more detailed financial estimate with the feasibility studies. I propose that @reef-finance takes ownership of studying these.