The four families
| Family | What it covers |
|---|---|
| Design and supervision | fees of the design team |
| Acquisition | duties, notarial fees and disbursements |
| Connections | service connections up to the building |
| External works | terrace, access, boundaries, planting |
These four families do not arise at the same moment, which partly explains why they are forgotten. The first are paid before the site starts, the last after it ends.
Nor do they involve the same counterparts, which makes them less visible than a main contractor's quotation.
Why they are underestimated
Three reasons, all structural.
They appear in no single quotation. No document brings them together, unlike construction cost.
They spread over time. A client tracking their budget month by month may never see the consolidated total.
Some are perceived as optional. External works in particular are frequently deferred then carried out, which removes them from the initial budget without removing the need.
The result is a drift perceived as an overrun, when it is an omission at the outset.
What differs in Luxembourg
Two features worth knowing before estimating. They concern the fees and the registration duties.
Duties on acquisition apply to different bases depending on the type of transaction. For construction they do not apply to the whole project, a point developed in the article on notary fees and duties.
Tax credit and reduced-rate schemes exist and may materially change the amount actually borne. They belong to the guide on tax and housing support, and they require prior steps.
Failing to check these schemes before the deed or before works can cost considerable amounts, most requiring a prior application rather than a later refund.
The most frequently forgotten item
External works.
Three reasons for the omission.
They are excluded from turnkey offers, as the article on shell and turnkey explains.
They arise at the end of the project, when the budget is already committed.
Their scope is elastic. A terrace, an access and a boundary form a functional minimum; the rest is added in stages.
Treating them as a costed item from the outset avoids discovering at the end of the works that they are unfunded.
The order of magnitude and its use
A methodological precaution.
The fifteen to twenty per cent order of magnitude applies to construction cost, not to the total budget nor to land cost.
It serves to check an estimate, not to produce one. A serious estimate costs each family separately, as the article on building an item-by-item estimate explains.
A share well below that order of magnitude generally signals an omission, most often external works or connections.
The articles in this branch
The article on design fees covers the remuneration of the participants. The usual rates are given there.
The article on notary fees and duties covers what is paid on acquisition. The calculation is detailed there.
The article on connections and external works covers the end-of-project items. The items are quantified there.
This article reflects the state of the data at the date of checking and serves professional orientation. It does not replace tax advice or consultation of a notary.