The 12 phases of a Belgian construction project: what happens, who decides, and when

01The twelve phases at a glance

A quick summary. One sentence per phase. Bookmark this piece if you want to return to it later.

• Phase 0, Preparation. Budget framework, financing pre-check, brief of requirements.
• Phase 1, Land and location. Plot search, soil certificate, urban planning information, notarial deed.
• Phase 2, Architect selection and design. Appoint architect, preliminary design, final design.
• Phase 3, Studies and advice. Energy performance (EPB), ventilation, structural engineering, safety coordinator.
• Phase 4, Permits. Apply for environmental permit, appeal period, public posting.
• Phase 5, Contractor selection. Specifications, quotes, comparison, awarding.
• Phase 6, Financing and contracts. Take out the construction loan, sign contractor agreements, set up insurance.
• Phase 7, Groundworks and foundations. Surveying, excavation, foundations, possibly a cellar.
• Phase 8, Shell. Walls, floor slabs, roof structure. Wind and watertight.
• Phase 9, Technical installations. Electrics, plumbing, heating, ventilation. First-fix first, then finishing.
• Phase 10, Finishing. Insulation, plastering, floors, painting, kitchen, bathroom.
• Phase 11, Acceptance. Provisional and final acceptance, EPB declaration, moving in.

02Phase 0: Preparation

What happens

Before you look for a plot or call an architect, you lock down three things. One: what you are going to build or renovate, in what direction. Two: how much it can cost, all in. Three: how much you can actually borrow or put in yourself.

This is the phase most homeowners skip. They see a plot they want, and the maths comes afterwards. That is an expensive order of operations.

Who decides

You. Possibly with a financial advisor or an initial exploratory chat with a bank.

What is locked in after this phase

Your indicative budget. The headlines of your brief of requirements. A rough sense of what your bank considers feasible.

Where the budget sits

Not much concretely spent yet. But this is the moment to build in your buffer. A margin of 10 to 20% on top of your estimated build sum is customary, and for renovating older homes leans towards the higher end. How to build and track that budget concretely is in the article on tracking your construction budget.

03Phase 1: Land and location

What happens

For new construction: search for a plot, negotiate the price, request urban planning information from the municipality, request a soil certificate from OVAM, possibly have an exploratory soil survey done, sign the notarial deed. For renovation: buy or inventory an existing dwelling, and request the same urban planning information.

For the sale of land in Flanders the seller must request a soil certificate from OVAM and disclose its content to the buyer [7]. A blank certificate tells you OVAM has no risk data on the land, but is not proof that the land is uncontaminated.

Who decides

You, in consultation with the notary. If there is any doubt about soil or zoning: a survey office or specialised advisor.

What is locked in after this phase

Your location. Your build zone on the cadastre. Easements, pre-emption rights, orientation. What you miss here you cannot fix later without large costs.

Where the budget sits

Purchase price of the plot. Notary fees and registration duties. Soil certificate. Any soil surveys. For an existing dwelling those last items can turn out expensive.

04Phase 2: Architect selection and design

What happens

Contact one to three architects, an introductory conversation, request a proposal, choose. After that the design work starts in steps: preliminary design, final design, execution dossier.

For every building project that requires an environmental permit, the involvement of an architect is legally mandatory. That is article 4 of the law of 20 February 1939 [2]. The architect designs and supervises execution. That is not a formality.

Who decides

You, together with the architect. This is where your brief translates into drawings.

What is locked in after this phase

Your floor plan. Your facades. The volumes. The size of the windows. The location of the kitchen and bathrooms. Things that change in phase 10 usually trigger large redesigns.

Where the budget sits

The architect's fee, typically as a percentage of the build sum. A market range of 6 to 12% is common, varying with complexity and the level of guidance. No legally fixed tariff.

05Phase 3: Studies and advice

What happens

In parallel with the final design, the mandatory studies come in. An EPB reporter is appointed for the energy performance calculation. A ventilation reporter monitors the ventilation dossier. A stability study is drawn up, often by an engineering firm. And for sites with several contractors you appoint a safety coordinator.

On sites with two or more contractors a safety coordinator is legally mandatory (Royal Decree of 25 January 2001) [5]. For sites larger than 500 m² it is always the homeowner who appoints both the design-phase and execution-phase coordinators.

Who decides

You, on the architect's recommendation. In practice every architect works with fixed partners for stability and EPB.

What is locked in after this phase

The technical baseline of your home. Insulation values. Ventilation principle. Load-bearing structure. Things that later become irreversible because they sit in the permit application.

Where the budget sits

EPB and ventilation reports together typically run from a few hundred to over a thousand euro. Stability study depending on complexity. Safety coordinator often a fixed amount per phase. All items people forget to include in their starting budget.

06Phase 4: Permits

What happens

Your architect submits the environmental permit application via the Omgevingsloket. The municipality or province handles the file. There may be a public enquiry. Then comes the decision, and the posting on the plot.

The decision period in the standard procedure is 105 days without advice from the omgevingsvergunningscommissie, and 120 days with advice [3]. With a public enquiry or an administrative loop, that period can be extended once by sixty days.

Then more waiting. An appeal against an environmental permit must be lodged within 30 calendar days from the first day of public posting [4]. Works can only start from 35 days after that posting, if no suspensive appeal is lodged [4].

In concrete terms: between submitting the application and being able to actually start, a normal scenario runs four to five months. A more complex file runs longer.

Who decides

The licensing authority (usually the municipality). You are the applicant, via your architect.

What is locked in after this phase

What you are allowed to build, as it stands in the file. Changes after the permit often require a new application or a notification.

Where the budget sits

File fees from the municipality. Sometimes publication costs. Not a large item overall, but the time is a cost: during this phase you cannot start works.

07Phase 5: Contractor selection

What happens

On the basis of the execution dossier you request quotes. Preferably three, drawn up comparably on the same specifications. You compare, you ask questions, you negotiate, you award.

This is the phase with the largest financial effect after the design. The difference between quotes for the same work can run into tens of percent. Not because the contractors are dishonest, but because they interpret scope differently or leave items out.

The sector is under pressure. In 2025, 2,780 Belgian construction businesses went bankrupt, a record [1]. Anyone who signs without checking the financial health of their contractor takes a risk that can be reduced in 30 minutes. How to handle that is in the article on vetting your contractor. How to lay three quotes side by side fairly, you can read here.

Who decides

You. Possibly with advice from your architect.

What is locked in after this phase

The price and scope per contractor. The execution schedule in broad strokes. Which lots you bundle under one general contractor or tender separately.

Where the budget sits

This is where 80 to 90% of the build sum is locked in. What you miss or misjudge here comes back in phase 10 as additional work.

08Phase 6: Financing and contracts

What happens

With the accepted quotes you go to your bank. The construction loan is finalised based on the real build sum and the drawdown schedule. At the same time you sign the contractor agreements and arrange the insurance.

A construction loan is drawn down in tranches, not all at once [11]. You pay interest on the drawn amount, and typically a reservation fee on the balance not yet drawn. The drawdown schedule is matched to the progress of works.

For works requiring a planning permit, the ten-year liability insurance has been legally mandatory since 1 July 2018 (Peeters-Borsus law) [8]. That applies to contractors and architects alike. Ask for the insurance certificate before you sign.

Who decides

You, with your bank and your insurer. This is also where you fix the VAT rate: 6% for renovations of homes older than ten years [9], and since 1 July 2025 also 6% for demolition and rebuild by private individuals under conditions (sole and own dwelling, maximum 200 m² habitable area, combined permit for demolition and rebuild) [10]. For classic new construction the rate stays at 21%.

What is locked in after this phase

Your payment schedule. Your drawdown schedule with the bank. Your insurance coverage. The clauses you have negotiated on additional work, delay, and acceptance.

Where the budget sits

Deed fees from the bank for the construction loan. Premiums for the ten-year liability and the ABR insurance (all-site risks), which is not mandatory but recommended on larger projects.

09Phase 7: Groundworks and foundations

What happens

A surveyor stakes out the plot. The groundworker excavates. The contractor or a specialised firm pours the foundations, possibly a cellar. The first big visible step.

Who decides

Mainly the contractor and the architect when in doubt. You decide on additional work, for instance if the ground turns out to be less load-bearing than assumed.

What is locked in after this phase

The position and elevation of your home on the plot. Moving after this phase is not an option.

Where the budget sits

The first large tranche of your construction loan is typically drawn here. Invoices from the groundworker, the concrete supplier, the cellar builder.

10Phase 8: Shell

What happens

Walls in concrete or masonry, floor slabs, roof structure, windows installed. By the end of this phase your home is wind and watertight. That is a formal milestone for your construction loan and your insurance.

Who decides

The contractor executes according to the specifications. The architect supervises. You decide on changes or additional work.

What is locked in after this phase

The volume is fixed. Re-arranging layouts after this phase becomes expensive, because load-bearing walls and concrete floors don't move easily.

Where the budget sits

The largest tranche of your construction loan. Wind and watertight is a key milestone in most drawdown schedules.

11Phase 9: Technical installations

What happens

Electrics, plumbing, heating and ventilation are installed. First the rough installation (pipes, cable runs, ventilation ducts), then the finishing. Between those two sit plastering and screed.

Sequencing makes the difference here. Socket positions, light switches and sanitary drains must be in place before plastering and screed begin. Anyone who decides late here either reworks or compromises.

Who decides

You decide on positions and types. The contractors and the architect manage execution and sequencing.

What is locked in after this phase

Where your sockets sit, where your pipes run, what heating system you finally have. Relocating after screed is relocating at extra cost.

Where the budget sits

A labour-intensive phase. Often spread over several contractors, which requires coordination: technical-installation contractors work in parallel or just behind one another.

12Phase 10: Finishing

What happens

Insulation, plastering, screed, floors, painting, kitchen, bathroom, internal doors, stairs. Hundreds of small decisions in a few months. This is where most additional work originates.

Who decides

You decide on materials, colours, types. For every decision there is a price tag and a lead time. Suppliers of kitchens, sanitary ware and parquet work weeks to months in advance. Whoever orders only when the site is ready, slows themselves down.

What is locked in after this phase

Almost everything you see and touch daily. The margin to adjust narrows.

Where the budget sits

Many smaller items together. This is where most additional work lands, because the scope in phase 5 was rarely fully complete. Read how to actively track your budget during this phase so deviations don't pile up into a surprise at the end.

13Phase 11: Acceptance

What happens

The provisional acceptance: you and your architect walk through the home, note remaining defects and finishing points, and draw up a list of what the contractor still has to resolve. After that a warranty period starts. In most contractor agreements there is one year between provisional and final acceptance. That is contractual practice, not a statutory deadline.

At the same time you must submit the EPB declaration. The EPB declaration must be filed no later than twelve months after occupancy or completion of the works, and in any case within five years of the permit being granted [6]. Missing the deadline risks a penalty.

Who decides

You sign the acceptance. The architect supervises. The contractor confirms execution.

What is locked in after this phase

The work is accepted, with or without reservations. The ten-year liability period begins to run, contractually usually from provisional acceptance.

Where the budget sits

Final tranches of the construction loan. Often a small final settlement with the contractor. EPB reporter invoices after the declaration. Moving costs, connections, fitting out.

14Why sequence matters for your budget

The phases look like a checklist. They behave like a dependency graph.

A few examples of how early decisions translate into costs later.

In phase 2 you choose a heat pump rather than a condensing boiler. That changes your required insulation values, your underfloor heating, your pipe diameters, and your EPB score in phase 11. Anyone trying to reverse that in phase 9 pays twice.

In phase 5 you opt for a single general contractor instead of separate lots. That simplifies your coordination in phases 7 to 10, but it can cost you a margin on the specifications in phase 6. Or the reverse: separate lots can be cheaper on paper, but every coordination mistake in phase 9 costs a day of work.

In phase 6 you sign a contractor agreement with a payment schedule that doesn't match your bank's drawdown schedule. The difference you bridge in phases 7 to 10 with your own funds.

These are not edge cases. This is how a normal build runs.

The underlying logic is that some decisions have a long lead time. A kitchen order that has to arrive in phase 9, you place in phase 5 or 6. A heating choice that determines your EPB in phase 11, you fix in phase 2. Whoever reads the phases as a list, decides at the wrong moment.

15What most homeowners get wrong

Three patterns come up again and again.

Taking decisions too late. "We'll pick a kitchen once the walls are up." That sounds reasonable, but kitchen suppliers work weeks to months ahead, and you need socket positions for the plastering in phase 9. Anyone who starts choosing in phase 10 chooses under pressure.

Treating phases as strictly sequential. They overlap. The permit procedure runs while you are already comparing quotes. Studies start in parallel with the design. Whoever waits for phase N to wrap up before starting N+1 adds months to their lead time.

No system to track decisions. An average construction project runs twelve to eighteen months. Hundreds of decisions, spread across WhatsApp, email, a kitchen-table notebook, and the memory of four people who each remember something different. Three months later the contractor asks which colour tile you had agreed. And no one remembers.

None of those three is a lack of effort or intelligence. They are predictable failure patterns of a process that is too complex to keep in your head.

16What this means for your project

Knowing the twelve phases is step one. Knowing where the decisions sit is step two. Tracking them without losing the thread is step three.

A good construction project isn't a series of heroic moments. It's a series of small, informed choices, at the right moment, by the right person, with the right information. Anyone who can organise that kind of discipline delivers a home in phase 11 that costs roughly what they expected at the start.