Architect fees in Luxembourg (2026)

Tariff structure:

• Percentage of works cost — the OAI-referenced approach for new builds and major renovations. A €400 000 construction yields a €36 000–€52 000 fee for a full 9–13 % mission.
• Fixed fee per phase — the preferred approach for small renovations and single-phase mandates, because it caps the client's exposure regardless of how the works cost moves.
• Hourly rate — used for initial feasibility, urban-plan liaison, or disputes. €95–€160/h excluding TVA is the current Luxembourg-Ville band.

A fee quoted net at €5 500 HT with TVA 17 % lands at €6 435 TTC. Always clarify whether the percentage in a proposal is applied to the HT works cost or the TTC works cost — a 10 % fee on a TTC base is roughly 12 % on the HT base.

The OAI reference schedule splits a full mission into nine phases. Knowing the code helps you negotiate a partial mission without missing a critical phase.

The nine phases in sequence:

• APS — Avant-Projet Sommaire. Concept sketches, volume studies, target budget. ~8 % of total fee.
• APD — Avant-Projet Détaillé. Detailed design, material selection, technical brief. ~14 %.
• PAP — Procédure d'Aménagement Particulier. Only if the project requires a PAP amendment from the commune. variable.
• PE — Projet d'Exécution. Construction-issue drawings, specifications. ~22 %.
• DCE — Dossier de Consultation des Entreprises. Tender package sent to contractors. ~8 %.
• ACT — Assistance pour Contrat de Travaux. Bid evaluation, contract drafting, signing. ~4 %.
• DET — Direction de l'Exécution des Travaux. On-site supervision, attendance at weekly meetings. ~33 %.
• AOR — Assistance aux Opérations de Réception. Snag list, handover, warranty release. ~6 %.
• DOE — Dossier des Ouvrages Exécutés. As-built drawings, maintenance file. ~5 %.

Common partial missions:

• Permit-only: APS + APD limited to permit drawings — typically 15–20 % of a full fee
• Design only, no supervision: APS + APD + PE + DCE — typically 52 %
• Supervision only: DET + AOR + DOE — typically 44 %

For a rear extension or a full renovation, DET is the phase where most client issues arise. Drop it at your own risk — an unsupervised build usually costs 6–10 % more in rework.

Luxembourg regulation requires an OAI-registered architect for most building permits. A quick decision tree saves you a trip to the commune.

Architect is required for:

• Any autorisation de bâtir above 80 m² gross floor area — the threshold applies to the full constructed volume including basement and usable attic
• Any exterior modification that changes the façade, the roof silhouette or any element visible from public space in a listed zone (secteurs protégés) or heritage commune
• A new-build on a previously undeveloped parcel, regardless of size
• Any structural modification — load-bearing wall removal, floor opening, roof raising
• A change of use from residential to commercial or mixed

Architect is not strictly required for:

• Interior refurbishment that does not change structure, layout or façade (kitchen renovation, flooring, interior painting)
• Small garden structures under 20 m² with no foundation (garden sheds, pergolas) — most communes accept a déclaration de travaux without architect seal
• Solar-panel installation, heat-pump swap, window replacement with equivalent aperture

Ingénieur-conseil, not architect:

• Purely structural work (reinforcement of a beam, foundation underpinning) is usually signed by an ingénieur-conseil structure, not an architect — a separate OAI profession with its own reference tariff
• Energy-performance declarations (CPE, passeport énergétique) are filed by qualified energy consultants

When in doubt, ring the service urbanisme of the commune before you sign anything. A 15-minute call saves a 3-month permit loop.

Architect fees in Luxembourg are subject to TVA at the standard 17 %, regardless of whether the downstream construction work qualifies for the reduced 3 % rate.

Rate in practice:

• Architect fee on a new-build: TVA 17 %
• Architect fee on a renovation that qualifies for 3 % TVA on works: architect still at 17 % — the reduced rate applies to construction services, not to intellectual services
• Architect fee on a commercial or rental project: TVA 17 %, potentially deductible by a TVA-registered client

Private-client reality:

• The TVA on architect fees cannot be claimed back by a private homeowner — it is a cost line in the total project budget
• On a €6 000 net fee, the TVA line adds €1 020 that does not recover

Partial deductibility for rental landlords:

• A landlord registered for TVA on a commercial rental can deduct architect TVA on that building
• A residential rental is TVA-exempt — the landlord cannot deduct the architect TVA but the full fee is deductible as a "frais d'entretien" or "frais de réparation" against rental income for the tax year in which the work is completed

Invoice checklist:

• Architect TVA number and OAI registration reference
• Phase breakdown (APS, APD, etc.) with fee per phase
• Reference to the signed OAI framework contract
• Indemnity-insurance policy reference (required by law)

Ask for the invoice to be split by phase rather than in a lump — it helps if you discontinue the mission before DET starts.

Architect proposals are easy to misread because fee structures differ — percent of works, fixed fee, or hourly rates with cap. Use a shared brief to force apples-to-apples comparison.

The six checks that matter:

• Fee structure. Is it percent of works (HT or TTC?), fixed fee per phase, or hourly with cap? Ask for the implied percent of works on a named target budget.
• Phases covered. Which of the nine OAI phases are in scope? A proposal covering APS-APD-PE but silent on DET is under-scoped for any build.
• Implied works budget. A proposal at 10 % of a €250 000 budget for a new-build is suspiciously low — verify the budget basis.
• Consultant integration. Structural engineer, thermal consultant, CPE: included in the architect's fee or subcontracted to the client at cost?
• Site visits. How many DET visits per month during the build, and what is the rate for additional visits above the included number?
• Professional insurance. OAI registration number and RC Pro policy reference belong in every proposal.

The briefing pack to send:

• One-page brief with surface target, number of rooms, target budget range (HT and TTC)
• Existing plot plan, cadastral extract, any previous drawings
• Photos of the existing building if renovation
• Target start date and flexibility
• Contract phase intent (full mission, design only, supervision only)

Where architects diverge:

• Design-led firms tend to cost more in APS-APD (better design output) but less in DET (few changes during build)
• Construction-led firms tend to be cheaper in APS-APD but bill more DET visits as the build evolves

Interview at least three. A 30-minute conversation reveals reading-of-brief fit more than the number on the page.

A sense of budget envelope helps you decide whether a proposal sits in the Luxembourg market or outside it.

Reference envelopes (TTC, architect + all consultants + TVA 17 %):

• Apartment refresh with permit (façade change, layout): €4 000–€7 000
• Full apartment renovation with structural change: €7 000–€13 000
• Rear extension 25 m², single-family home, permit + supervision: €12 000–€22 000
• Roof conversion to habitable attic: €15 000–€28 000
• New-build single-family home, 180 m² gross, turnkey mission: €35 000–€55 000
• New-build two-unit house, shared staircase: €55 000–€85 000
• Small commercial fit-out with permit: €6 000–€15 000
• Renovation of a listed façade: €8 000–€18 000 (authority liaison eats hours)

What drives the spread:

• Urban versus rural commune. Luxembourg-Ville and Esch-sur-Alzette carry 10–20 % premium over Mersch or Diekirch.
• Listed-heritage liaison. Secteurs protégés add €2 500–€5 000 in back-and-forth with the heritage service.
• Consultant count. A thermal consultant, a structural engineer, a fire-safety consultant and a CPE preparer are four separate line items outside the architect's own fee.
• Speed of decision-making. Slow-deciding clients drive up DET hours — a fast client pays close to the bottom of the range; a hesitant client closer to the top.

Ask for a budget envelope letter before signing the OAI framework contract: it commits the architect to a cost target within ±15 % and is the single most useful control document a private client can demand.