Phase 2 PAP not adopted: can the commune refuse a compliant-density scheme?
Commune de Rumelange. A developer owns a 41-are parcel in zone HAB-2 under the PAG adopted in 2018. The PAG sets a maximum CUS of 0.7, a maximum of three storeys and a 6 m front setback. The parcel lies inside the perimeter of a PAP 'nouveau quartier' approved in 2021, but the detailed PAP for phase 2 - where the parcel sits - has not yet been adopted; only the phase 1 plan de detail exists. The developer files a building permit for 13 flats, 980 m2 net floor area, 16 parking spaces and a roof terrace. The commune's planning service returns the file as 'premature' and points out that the PAP will require 25% affordable housing and a 4 m wider pavement. The developer argues that the PAG density is met and that the PAP cannot add requirements retroactively. The parcel has an existing 1950s house that would be demolished.
1. The commune refuses the permit as 'premature'. Is that legally sound, and can the developer rely on the PAG density alone?
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The refusal is likely sound. Under Luxembourg planning law, a building permit must comply with both the PAG and the applicable PAP. The PAG is the general plan; the PAP is the detailed plan that fixes buildable envelopes, access, servicing, parking, landscaping and, where the commune has decided so, affordable-housing obligations. A project inside a PAP perimeter for which no detailed PAP has yet been adopted has no approved detailed rules against which the commune can lawfully assess it. The commune can therefore refuse as premature, or apply a suspension of decisions, rather than grant a permit that would pre-empt the PAP.
The developer's 'retroactivity' argument is misdirected. The PAP does not retroactively invalidate the PAG; it conditions future permits. There is no acquired right to build at the PAG's maximum density before the PAP is adopted. The PAG density is necessary but not sufficient: compliance with the PAP, the PAG's own prescriptions and the commune's urbanistic servitudes is also required. The existing 1950s house does not create a right to a larger replacement scheme. The permit file should not be treated as a simple density check; the phase 2 PAP is the missing legal layer.
2. Calculate the PAG density envelope and explain what the 25% affordable housing and 4 m pavement mean for the scheme.
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41 ares = 4,100 m2. At CUS 0.7, the maximum gross floor area is 4,100 x 0.7 = 2,870 m2. The proposed 980 m2 is far below that ceiling, so density is not the obstacle. Even a generous reading of the net-to-gross relationship would leave substantial headroom. The issue is layout and obligations, not over-density.
A 25% affordable-housing requirement could be applied to units or to floor area. On 13 units, 25% = 3.25, so the PAP would normally require at least 4 affordable units; on floor area, 25% of 980 m2 = 245 m2. The developer should not assume that 'affordable' means a smaller unit mix without design consequences: it affects tenure, parking, access and finishing. The 4 m wider pavement reduces the buildable depth and may make the 16 surface parking spaces impossible to fit at grade, pushing parking to a basement or a collective courtyard. That changes cost and possibly the number of units. The scheme may still be feasible, but it must be redesigned around the PAP envelope rather than defended on the PAG CUS alone.
3. What procedural route can the developer take to unlock phase 2, and what are the main risks?
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The developer should ask the commune to prepare and adopt the phase 2 PAP, or check whether the commune will accept a privately initiated PAP dossier for that phase. The route is a planning procedure, not a building-permit argument: draft the plan de detail and reglement, integrate the affordable-housing obligation, the wider pavement, servicing and parking, carry out the public enquiry and obtain the commune's adoption. The developer can offer to fund technical studies and infrastructure, but cannot buy the outcome.
Risks: the commune may re-phase the perimeter or require infrastructure contributions; the affordable-housing obligation may reduce residual land value; a phase 1 precedent may not bind phase 2; and the existing house may be subject to demolition or heritage review. Starting demolition before the PAP and permit are secured would be an enforcement risk. A realistic strategy is to negotiate a pre-application meeting, obtain written planning assumptions, and make the permit application conditional on the adopted phase 2 PAP rather than filing a scheme that the commune must refuse.