oh, not written in. I had €6000 on the list (the Ytong prefabricated elements were separate... so if you count them in, about €14,000) The chimney should still be built up in the heating room and then go up as a steel pipe... however, I included the steel pipe itself in the heating construction costs and not in the shell construction. Architect fees will be minimal or almost zero due to a favor (an acquaintance of a relative... plus in the end there won’t be much left to do, only minor adjustments. Even though the topics of building regulations, energy ordinance and fire protection already annoy me, it takes effort to learn them). But even if a few thousand are added on top, I hope I have enough buffer.
In my calculation, I always assumed the very first prices I found... there is certainly optimization potential everywhere. The slab for 120 sqm should also be cheaper than €15,470. Of course, some things will also be missing, so here is the question what is missing or what cannot be accounted for in order to keep refining the calculation.
I did not include scaffolding since I would build from the inside anyway and own a small scaffold (and might buy a second one if needed... but the €300 wouldn’t make much difference). It gets interesting when plastering outside, but I haven’t included that in the shell construction yet.
Earthworks are mostly done, soil was compacted and if something still has to be removed it can be spread on the site (about 50 cbm will still be needed anyway). By supply connections, do you mean water/sewage, electricity, gas? They are relatively conveniently located to the private house, so not much will have to be done. The sewage shaft is, for example, only about 4 meters from the construction site, water supply is also located there.