Legal questions about staircase renovations

Questioner

I had a steel spiral staircase (left-turning) and a loft ladder replaced with two wooden staircases (right-turning) in my home. The new staircases are steeper and narrower than the old ones. And it hasn't improved anything. I've consulted with the municipality, a structural engineering firm, and architects, and they all tell me the same thing: 1) If it's a concrete (sandwich) floor, it's advisable or mandatory (?) to consult an expert (structural engineer) for advice. …… or, to put it another way, ……. It must be demonstrably safe (stated in the building code). This safety is demonstrated through calculations. These calculations are performed by a structural engineering firm or by someone within the firm with the necessary expertise.  BUT WHERE IS IT STATED IN THE BUILDING DECREE? 2) The new stairs must be at least equal to the existing ones or better. This means: the tread, tread, handrails, stair gates. (and the prevention of contact noise). This also applies if the old left-turning stairs are replaced by a new right-turning stairs? ………..or put differently…….. the new stairs must always be an improvement in all aspects (stated in the Building Decree)  BUT WHERE IS IT STATED IN THE BUILDING DECREE? Could you please help me and tell me where this is stated in the building code? This concerns an existing home. Thank you.

Questioner

If I understand correctly, you now want to install (again) two new staircases and make them less steep, thereby removing a section of the floor. If you're making structural changes to the house, I think you'll want to be sure they're done responsibly. Therefore, it's advisable to have a calculation made of the changes you intend to make. Although I can't find in the building code that the new staircase must be an improvement in all aspects, I assume you want the staircase to be better than the old one; otherwise, why would you replace it?

Questioner

No, I had the spiral staircase and the loft ladder replaced with two wooden staircases, which are now in the house. The staircase company assured me that everything would be done according to regulations and that the new staircases would not be steeper and would have the same large tread as the old spiral staircase, even though they would now be mirrored. They also told me that there was no need to do calculations for cutting the attic floor. I now have serious doubts about whether he lied to me and cheated on me. And when I ask other agencies for help, I'm told what I wrote in the previous letter.

Questioner

Cutting into an attic floor can lead to structural changes. This applies to wooden floors where beams are cut, or to concrete floors, particularly if reinforcement is removed. The building code specifies the various NEN standards that the floor must meet after a section has been removed. Requirements for the stairs are stated in section 2.33 and further of the Building Decree.

Questioner

It's possible that the old staircase didn't comply with the regulations for existing buildings. In that case, when renovating based on the regulations regarding "acquired rights," you're not always required to install a staircase that meets the requirements for new construction. However, in such a case, it's not permitted to install a staircase that exacerbates the deviation from the regulations. This is likely the problem.