March 2026, hotel in Genappe, 11:17pm. For the third time I re-read the permit plans and the execution plans of a project I will receive the next morning at 9am. Three discrepancies appear — invisible by day, obvious at night. I have lived through this moment several times in my career, and it confirms a rule I learned in my first year: never sign reception minutes without having re-read the plans coolly, the evening before. Without that nighttime re-read, the three discrepancies identified that evening would have cost my clients €14,200. Step-by-step account.
Discrepancy 1: a bay window moved by 80 cm
Permit plan: bay window aligned on the living-room axis, opening 240 cm. Execution plan delivered the day before by the architect: opening 280 cm, shifted 80 cm to the south.
The change looks cosmetic. It is not. Possible consequences:
- Breach of the granted building permit (undeclared modification)
- Possible refusal of the planning compliance certificate by the municipality
- Risk of retroactive municipal formal notice
- Cost of bringing back into compliance (moving the bay, redoing lintels and supports): €8,400
See also building permit, when to check on planning compliance issues.
Discrepancy 2: under-sized roof insulation
Submitted EPC: R = 6.2 m²·K/W for the roof (equivalent to 25 cm of mineral wool or 18 cm of PIR). Technical sheet of the panel actually delivered: R = 5.1 m²·K/W (equivalent to 20 cm of wool or 14 cm of PIR).
The 1.1 m²·K/W gap represents 18% less performance on the roof, and a discrepancy large enough to shift the property from EPC-A to EPC-B. The property-value difference between these two classes, according to the approved experts I have consulted, lies between €12,000 and €18,000 for a €350,000 house.
Discrepancy 3: triple vs. double glazing
Contract quote: triple-glazed frames Uw = 0.9 W/m²·K. Frames actually installed: double glazing Uw = 1.3 W/m²·K.
Price difference per square metre: about €80. On the 28 m² of total glazed surface of the house, €2,240 to recover as a credit note or price reduction. The substitution was hidden under the wording “frames Uw EPC-compliant” without specifying the glazing type.
This is the classic trap of “equivalent” references in specifications — see comparing contract clauses for substitution loopholes.
Reception the next morning
I arrive in the morning with my three identified discrepancies, plans to back them up, precise measurements, technical references. Refusal to sign the minutes, verbal formal notice to the contractor, negotiation. Final result:
- Complete reworking of the bay window to permit dimensions (at contractor’s expense)
- Reworking of roof insulation with compliant product (at contractor’s expense)
- Credit note of €2,240 on the frames item (deducted from the balance)
- Negotiated total: €14,200 in reductions and reworking
Without the nighttime re-read, those three defects would have slipped through — masked by finishings and plasters, unrecoverable six months later.
Pitfalls to avoid
- Never sign reception minutes without a cool re-read of the plans the night before
- Always overlay permit plans AND execution plans
- Check the technical sheets of delivered materials
- Request delivery notes signed by the contractor
- Refuse “equivalent” references in the specifications
For the regulatory framework of EPC in Wallonia, see energie.wallonie.be.
What next?
If your reception is coming up, schedule a plans re-reading session 24 hours before the visit. My firm offers a provisional reception expert service that systematically includes this comparative re-read, or a broader construction audit.