I meant additional purchase costs GrErwSt and notary/land registry :) That roughly fits with the 10k... So rounded 520,000 budget - 150,000 land etc = 370,000 for turnkey house all inclusive minus your estimated 20,000 incidental construction costs (without earthworks and architect/energy consultant, since those have separate items with you) and 30,000 euro buffer. Garden is initially excluded or is that basically your buffer?
Roughly 8x11m - 20% wall share, two full floors = approx. 140 sqm planned net living area? 370k remaining budget after land purchase - 30k planned buffer = 340k results in approx. 2,450 EUR per sqm living area incl. incidental construction costs and without (!) planned own contribution except for painting... I suspect that the calculation figures of the house providers you are using here are rather pre-Corona prices or some things are missing - you definitely have to be careful! Of course, it doesn't always have to be 3,000-3,500 EUR per sqm, but prices under 2,500 per sqm are usually only achieved if you basically do everything yourself...
How much customization potential is there with your house builder? Do they also paint the facade? If not, you can't just do two coats over a weekend, besides the paint you also have other consumables as well as scaffolding for longer or even new. Is side sealing of the base plate included or is that on-site? Drainage around the house? What else comes on top of your mentioned costs for electrical and sanitary? Base price or already customized? I don't see anything about screed... Is the carport assembled or just the kit? Keep in mind that you also have to prepare the ground accordingly; you can't just place it on the lawn. Who sets up the scaffolding and does the site setup? Do you need a compacted crane platform? Construction waste, container, who removes the leftover earth? That can quickly cost quite a lot of money... Do you have a construction manager/construction supervisor/expert? The cistern is good, but the earthworks for it and the connection as well as pump and pipes also belong to it.
Then the walls... Are they only up to and including plasterboard? Do you want to put wallpaper on directly or plaster/prime/sand/... ? Are you laying the floorboards yourselves? What about tiles in the wet rooms? I don’t see anything about stairs... Are they included? Assembly too? Do you have delivery costs for the kit?
I'm sure I can think of more... But since we are currently also planning with a kit, we are quite familiar with the subject... Sorry for the wall of text – it was more of a brainstorming!
- Garden is excluded - My girlfriend wants to paint the facade. I already told her it's a lot of work... - Probably no sealing of the base plate included...do you mean the plinth? - Drainage around the house not yet considered - Screed included on the upper floor, ground floor is nowadays smoothed concrete - Electrical already customized (more sockets and network cabling), switch series still Busch-Jäger I think... - Carport only kit, maybe later have it assembled or barter with the craftsmen... - Carport foundations or shed foundations 2,750, but full-surface price; we probably don't want that. Point foundations for the carport suffice in our opinion. Only the shed needs a base plate. - Scaffolding and site setup on-site, included in calculation - No crane platform - Container brought by construction company - Land is level, slightly lower than the access roads. - You're right, earthworks for the cistern aren't included in the estimate yet but shouldn't break the bank, should they? Connection either by earthworker, plumber, or my uncle, who is a plumber - Interior walls probably plaster-prime-sand, either self or outsourced to a drywaller, we don't want wallpaper. But that's my girlfriend's task :) - Tiles will be added, included in the floor estimate; laying probably done by my girlfriend, probably only on shower walls. - Staircase included, 4,250 the stairs and 1,250 the assembly - Delivery costs are included Thank you very much for your comments! :)