NRW BauO 2018: third amendment effective 1 Sep 2026—3‑month approval‑by‑silence for §64 simplified permits; impacts on attic conversions and rooftop PV in Cologne and Düsseldorf

What changed on 1 September 2026

North Rhine‑Westphalia’s third amendment to the Bauordnung 2018 (BauO NRW 2018) took effect on 1 September 2026. The consolidated statute now expressly introduces an approval‑by‑silence mechanism (Genehmigungsfiktion) for projects run under the simplified permit route in §64. §74(3) BauO NRW 2018 cross‑refers to §42a of the NRW Administrative Procedure Act (VwVfG NRW), making a simplified‑permit application deemed approved if the authority fails to reach a final decision within the statutory period, subject to conditions. The transition clause applies the fiction to applications filed from 1 September 2026. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/))

Separately, §63 BauO NRW 2018 was recast. Two points matter for housing investors: (1) in built‑up areas governed by §34 BauGB, the change and conversion of attics to residential use—including the construction of dormers—can be processed under the “approval‑free” notification route (Genehmigungsfreistellung) if set conditions are met; and (2) rooftop and façade solar installations were clarified elsewhere in the code as permit‑free in most cases. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/))

Rooftop PV also sits within a separate state‑wide obligation: §42a BauO NRW introduced a solar installation duty, implemented by the Solaranlagen‑Verordnung (SAN‑VO NRW) effective 19 June 2024, with staged start dates through 2026. ([recht.nrw.de](https://recht.nrw.de/lrgv/rechtsverordnung/19062024-verordnung-zur-umsetzung-der-solaranlagen-pflicht-nach-ss-42a-und-ss))

How the 3‑month approval‑by‑silence works in §64 cases

Timing has two layers after 1 September 2026:

- Decision deadline: §74(2) sets decision periods. For standard permits, the authority must decide within 3 months; for the simplified route (§64) and for pre‑decision notices (§77), it must decide within 6 weeks, counting from completeness. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/)) - Approval‑by‑silence: If a §64 application is not finally decided within the period governed by §42a VwVfG, the application is deemed approved. §42a sets a 3‑month fiction period by default (one justified extension allowed), starting on receipt of complete documents. In §64 cases, §74(3) tailors this fiction (e.g., it only covers requested deviations). The authority must issue an approval certificate and notify the municipality and any non‑consenting neighbours. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01012025-verwaltungsverfahrensgesetz-fuer-das-land-nordrhein-westfalen/?utm_source=openai))

Important caveats:

- Municipal consent steps under §36a BauGB can affect the clock. The law states the fiction/decision period ends, at the earliest, one month after the municipality’s decision reaches the building authority (or its §36a time limit lapses). Check this if your site needs municipal “Zustimmung.” ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/)) - The fiction gives procedural approval, not a substantive compliance guarantee. The official synopsis explicitly warns that the fiction does not prove the project meets technical rules—you remain responsible. ([bauordnung.nrw](https://www.bauordnung.nrw/paragraf/74-baugenehmigung-baubeginn/?utm_source=openai))

Attic conversions and dormers: where permits are still needed

NRW widened the “approval‑free” path. Since 1 September 2026, attic conversions to residential use—including dormers—can use §63 Genehmigungsfreistellung even in §34‑areas, provided that (i) access and services are secured and (ii) the municipality does not call the case into §64 within the one‑month review window. In planned areas (a binding Bebauungsplan), the conventional §63 path continues to apply if the project matches the plan and local design by‑laws. Construction may begin one month after filing the §63 documents if the municipality neither calls in the case nor seeks a temporary ban. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/))

However, two local layers matter in Cologne and Düsseldorf:

- Design by‑laws (örtliche Bauvorschriften/Gestaltungssatzungen): Genehmigungsfreistellung works only if the project does not conflict with local design rules (§89). Düsseldorf and Cologne have multiple district‑level design statutes constraining dormer shape, size and cladding. Examples include Düsseldorf’s Karlstadt and Benrath design by‑laws. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/)) - Monument protection: Alterations to listed buildings still require a monument permit in Cologne (including attic conversions). The city’s monument office sets specific conditions. ([stadt-koeln.de](https://www.stadt-koeln.de/service/produkte/01077/index.html?utm_source=openai))

Practice point: Düsseldorf’s Bauaufsicht notes that full attic conversions generally require a permit—even if interior works and roof windows alone might be permit‑free. Given the 2026 changes, always confirm with the Bauaufsichtsamt which route (Genehmigungsfreistellung vs. §64) applies to your building and street. If you choose §64, the new 3‑month fiction offers a backstop if the six‑week decision target is missed. ([duesseldorf.de](https://www.duesseldorf.de/bauaufsichtsamt/baulexikon-a-z/dachgeschossausbau?utm_source=openai))

Rooftop PV in Cologne and Düsseldorf: permits, obligations and exceptions

Permit status: Under §62(1) BauO NRW, solar installations in, on and at roof and external wall surfaces are permit‑free in NRW (except on high‑rises). PV within boundary setback areas is also broadly tolerated if 2.5 m from the property line; check spacing limits for your lot. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/))

Mandatory installation: NRW’s SAN‑VO NRW (in force since 19 June 2024) implements the solar duty in §42a BauO NRW. Key dates: non‑residential new‑builds with applications after 1 January 2024; municipal roofs with full roof renewal starting after 1 July 2024; residential new‑builds with applications after 1 January 2025; and any building with a full roof renewal starting after 1 January 2026. Minimum sizes (examples): 30% of gross roof area for new‑builds; for roof renewals, 30% of net roof area or 3/4/8 kWp minimums depending on dwelling count. Düsseldorf’s city page summarises these thresholds and the option to seek a hardship waiver. ([recht.nrw.de](https://recht.nrw.de/lrgv/rechtsverordnung/19062024-verordnung-zur-umsetzung-der-solaranlagen-pflicht-nach-ss-42a-und-ss))

Local overlays:

- Cologne: The city states that solar installations are generally not building‑permit‑required. Nevertheless, listed buildings require a monument permit; the city has published criteria and a guidance note for PV on monuments. Always verify whether a district design statute applies. ([stadt-koeln.de](https://www.stadt-koeln.de/mediaasset/content/pdf480/merkblatt_solaranlagen_-_barrierefrei.pdf?utm_source=openai)) - Düsseldorf: Local design and conservation by‑laws can constrain module placement in historic cores. Review district‑specific statutes (e.g., Karlstadt) and check with the Bauaufsicht if §36a BauGB municipal consent steps are triggered. ([duesseldorf.de](https://www.duesseldorf.de/stadtrecht/6/61/61-302?utm_source=openai))

Risk note: Even with Genehmigungsfreistellung or approval‑by‑silence, you remain liable for compliance with fire safety, structure, and neighbour rights. If you prefer legal certainty for financing or sale, consider opting into §64 to obtain a formal permit or, failing a decision, a fiction certificate. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/))」,

What to do next (buyers and expats)

- For attic conversions in Cologne or Düsseldorf, map your plot to its planning status (Bebauungsplan vs. §34 BauGB) and check for design by‑laws. If a design statute governs dormers in your street, Genehmigungsfreistellung only applies if you comply 1:1. Otherwise, use §64. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/)) - If you opt for §64, file a complete set and track the calendar. The authority should decide in 6 weeks; the approval‑by‑silence backstop runs on a 3‑month clock under §42a VwVfG NRW. Ask for the fiction certificate if the deadline passes. ([recht.nrw.de](https://recht.nrw.de/lrgv/gesetz/01092026-landesbauordnung-2018-bauo-nrw-2018/)) - Rooftop PV on existing houses is typically permit‑free statewide. Still, if your roof renewal starts after 1 January 2026, size your array to the SAN‑VO NRW minimums or document an exception. In listed areas, secure the monument permit first. ([recht.nrw.de](https://recht.nrw.de/lrgv/rechtsverordnung/19062024-verordnung-zur-umsetzung-der-solaranlagen-pflicht-nach-ss-42a-und-ss)) - Engage a locally licensed architect or civil engineer. Under NRW rules, you must self‑assure structural and fire safety in approval‑free routes; the city will not check these for you. For dormers, NRW’s guidance requires a qualified person to certify structural safety where used as a permit‑free element. ([bauportal.nrw](https://bauportal.nrw/dachgaube-bauen-nordrhein-westfalen?utm_source=openai))

This article is a general guide. It is not legal advice. For project‑specific questions, contact a local Architekt/in (LPH 1‑4), a Prüfingenieur/in for structure, and the Bauaufsichtsamt of Cologne or Düsseldorf.