One of the most common questions from VI invest customers: “Can the building authority ban a tiny house that has a registration plate?” The law’s answer is clear – and favorable for owners of an O2/O3-certified tiny house. Let’s look at what the Ministry for Regional Development itself says, along with the specific sections of the relevant acts.
The Ministry (MMR) itself divides mobile homes into two categories
In November 2025, the MMR issued an updated Methodological recommendation of the Building Regulations Department on mobile homes. Right at the start, the document establishes a key distinction:
“Not every ‘mobile home’ can be considered a structure within the meaning of Act No. 283/2021 Coll. Many ‘mobile homes’ are manufactured according to technical standards for recreational vehicles (e.g. ČSN EN 1949, ČSN EN 1647+A1), and therefore cannot be regarded as structures within the meaning of the Building Act, but as ‘mobile homes’ that are vehicles from the perspective of Act No. 56/2001 Coll.”
And immediately afterward, the MMR adds:
“This methodological aid deals exclusively with mobile homes meeting the definition of a structure within the meaning of the Building Act, not with mobile homes that are vehicles from the perspective of Act No. 361/2000 Coll. on road traffic.”
Translated without the legal jargon: the MMR itself says that the Building Act does not apply to vehicles.
What the specific sections of the acts say
The legal protection of a tiny house with a registration plate rests on three pillars:
- Section 6 of Act No. 56/2001 Coll. – defines the conditions for registering a vehicle. A tiny house with O2/O3 certification is registered as a towed vehicle and is, by law, a vehicle – not a structure or a product fulfilling the function of a structure.
- Act No. 361/2000 Coll. – the Road Traffic Act. The MMR directly cites it as the legal framework vehicles fall under – and one the Building Act does not reach into.
- EU Regulation 2018/858 – O2/O3 type approval issued by an accredited institution. As an EU member, the Czech Republic cannot use building regulations to restrict the free movement of goods that meet EU technical standards.
What O2/O3 certification means for a tiny house’s legal status
A tiny house with O2 or O3 certification undergoes type approval under EU Regulation 2018/858 and is registered in the vehicle register as a towed vehicle. This gives it:
- A registration plate and a vehicle technical certificate
- An obligation to undergo regular roadworthiness testing (STK)
- The legal status of a movable item – a vehicle, not real estate or a structure
- The right to move throughout the EU as a towed vehicle
Important note: Registration (a plate) alone is a necessary, but not sufficient, condition for protection. If a tiny house were to actually lose its mobility (see below), the building authority may initiate proceedings even despite valid registration. The key is maintaining actual mobility, not just mobility on paper.
What the Supreme Administrative Court (NSS) says
The key precedent is NSS ruling case no. 9 As 342/2016-21:
“At the moment this product loses its mobility, i.e. if its owner’s intent were to install it on land so that it starts to fulfil the function of a structure as its basic purpose, then such a product is fully subject to the permitting regimes under the Building Act.”
The reverse logic is key: as long as a tiny house does NOT lose its mobility, the Building Act does not apply to it.
When the building authority CAN intervene
Let’s be fully honest. There are situations where courts have sided with the building authority – specifically when a tiny house has actually stopped being a vehicle:
- It stands on permanent concrete footings (relocation would destroy it)
- The wheels or towing hitch have been removed
- It’s connected to utilities via concreted-in connections (not detachable connectors)
- The vehicle’s roadworthiness test and registration are invalid
The Regional Court in Brno (case no. 31 A 15/2014-46) ruled against the owner precisely because the object stood on concrete footings and was permanently connected to utilities – it had actually stopped being mobile.
When the building authority has NO authority
If a tiny house meets these conditions, the building authority’s substantive jurisdiction does not extend to it:
- It has a valid roadworthiness test and vehicle registration (a technical certificate)
- It has a functional towing hitch – the house is physically towable
- It stands on adjustable supports, not on concrete
- Utilities are connected in a detachable way (industrial connectors, hoses, extension cables)
The building authority may investigate, may ask questions – but without proving a loss of mobility, it has no legal tool to order removal.
The safety net: Section 103 of Act 283/2021 Coll.
Even in the hypothetical scenario where the building authority were to reclassify an O2/O3 tiny house as a “product fulfilling the function of a structure” (which is legally contentious), the following still applies:
Under Section 103(1)(e), item 16 of Act 283/2021 Coll., such products up to 40 m² do not require a building permit or a construction notification. So the Building Act is, even in the worst-case scenario, far from allowing the building authority to order removal without further proceedings.
Caution: modifications after installation may jeopardize certification
The O2/O3 certificate applies to the product as supplied by the manufacturer. If, after installation, you carry out:
- Adding or extending thermal insulation
- Opening new window or door openings
- Changing dimensions or weight
- Connecting fixed technology not covered by the certification
…this may cause the loss of certified-product status and require a new assessment. Consult the supplier before making any modifications.
EU law as additional protection
A tiny house with EU type approval (O2/O3) was placed on the market in compliance with European standards for towed vehicles. As an EU member state, the Czech Republic cannot use building regulations to restrict the free movement of goods that meet EU technical standards. Stricter national requirements beyond the EU standard are unacceptable from the perspective of EU law.
How to maintain your legal protection – summary
- Keep the roadworthiness test and registration valid
- A regular roadworthiness test is both a legal obligation and key evidence that the tiny house is still a vehicle.
- Mobile foundations, not concrete
- Adjustable screw jacks or steel pads – not permanent concrete footings.
- Detachable connections
- Water, electricity, and waste connected via standard trailer connectors or extension cables.
- Keep the towing hitch
- The tow ball must be functional and accessible. Never remove it.
- Document mobility
- Photos of the towing hitch, a valid technical certificate, the roadworthiness test – always have them ready.
- Don’t modify it without consulting the supplier
- Modifications after installation may jeopardize O2/O3 certification. Always consult in advance.
A tiny house from VI invest is supplied with a type-approval certificate and a vehicle technical certificate. These documents are your primary legal protection when dealing with any authority.
Have questions about your specific situation? Contact us or browse our O2/O3-certified models.
