1. Six questions in the right order
Each of them narrows the possibilities, and each assumes the previous one has been answered. The questions are asked in order.
| # | Question | Note |
|---|---|---|
| 1 | What the register records, including volume data | what to check in the register |
| 2 | Whether this is a residential or non-residential building | the requirements differ |
| 3 | What the built-up area and height are | both together, neither alone |
| 4 | What the type of activity is | erection, reconstruction, extension, demolition |
| 5 | If extending, by how much relative to the existing volume | the percentage is calculated from the registered volume |
| 6 | Whether special restrictions apply to the plot | protection zone, heritage protection |
Only then should the Building Code's Annex 1 in force be opened and the relevant row found. The table is the answer, not the starting point.
2. Why the order matters
Three reasons, and they bind the questions together. They explain why the order cannot be swapped.
The first question can invalidate all the others: if the register data are wrong, so is any percentage derived from them. The fifth question depends directly on the first, because the extent of an extension is calculated against the registered volume rather than the actual one.
The sixth question can reverse the result, because a restriction may require a procedure where the table says otherwise. Starting from the table is therefore the wrong order, however tempting a first step it makes.
3. When to ask the local authority
Four situations where asking in advance saves time and money. They concern unclear cases.
| Situation | Why ask first |
|---|---|
| The project is near a threshold | area, height or extension percentage |
| Register data and reality diverge | the procedure relies on the register |
| The plot carries a restriction of unclear scope | it may require separate approval |
| The type of activity is not unambiguous | the line between reconstruction and extension |
The fourth situation is more frequent than assumed, because the same work can be described in more than one way, and the description affects the procedure. This is not wordplay: the type of procedure follows from the type of activity, which makes describing the work part of determining the procedure.
4. The most frequent mistakes
Four mistakes all lead to the wrong procedure, and one of them is especially likely right now. It follows from the recent amendments.
| Mistake | Consequence |
|---|---|
| Working from memory | the table changed on 01.08.2026 |
| Looking at one variable only | area alone determines nothing without height |
| Trusting register data without checking | particularly volume data |
| Forgetting restrictions | they follow from the location, not the building |
The first mistake is the most likely in the second half of 2026, precisely because many practitioners have resolved similar cases before. Experience works against you here rather than for you.
5. What to do with the answer
Three next steps follow from the result, and their weight differs sharply. They range from a notice to a permit procedure.
| Answer | Next step |
|---|---|
| No procedure required | check restrictions and requirements nonetheless |
| Building notice | check whether a design is required, and allow 10 days |
| Building permit | check whether a detailed plan or design conditions are needed |
The third row weighs most in scheduling terms, because the planning basis may take up to three years or one to two months depending on which route applies. It has to be checked before commissioning the designer, not after.
Summary and four practical rules
The type of procedure is settled by six questions that begin with the register data and end with the plot's special restrictions, and only then is the Building Code's Annex 1 in force opened. The order is substantive: wrong register data invalidate everything derived from them, and a restriction following from the location can reverse the result. The most likely mistake in the second half of 2026 is working from memory, because the table changed on 1 August and earlier experience now works against you.
Four rules: start from the register, not the table. Look at all variables together rather than one at a time. Talk to the local authority when near a threshold, before the design is commissioned. Open the Annex 1 in force for every project afresh, regardless of past experience.
This article offers professional orientation as at the date of verification. It does not replace the assessment of the local authority.