The plot costs 137,100, notary and land transfer tax/land registry about 10,000 euros.
Do you mean the ancillary purchase costs by the additional construction costs? Those are currently about 20,000 euros.
By ancillary purchase costs I meant land transfer tax and notary/land registry :) That roughly fits with the 10k... So rounded 520,000 budget - 150,000 plot etc = 370,000 for the turnkey house all inclusive minus the 20,000 additional construction costs you estimated (excluding earthworks and architect/energy consultant, which have their own items with you) and 30,000 euros buffer. Garden is initially excluded or is that basically your buffer?
Roughly 8x11m - 20% wall portion, two full floors = about 140 sqm planned net living area? 370k remaining budget after plot purchase - 30k planned buffer = 340k results in about 2,450 EUR per sqm living area including additional construction costs and without (!) planned own contribution except painting work... I suspect that the calculation figures of the house providers you are calculating with here are rather pre-Corona prices or some things are missing - you really 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 basically only achieved if you do almost everything yourself...
How much customization potential is there with your house builder? Do they also paint the facade? If not, can that at least be done in one weekend by going over it twice, besides the paint you also have other consumables plus the scaffolding longer or even new. Is the lateral sealing of the base plate included or is that builder’s scope? Drainage around the house? What is still added to your mentioned costs for electrical and sanitary? Base price or already customized? I don’t read anything about screed... Is the carport assembled or only the kit? Keep in mind that you also need to prepare the ground accordingly, you can’t just place it on the lawn. Who sets up the scaffolding and does the site installation? Do you need a compacted crane area? Construction waste, container, who removes the remaining soil? That can quickly cost quite a lot of money... Do you have a site manager/site supervisor/expert? The cistern is good, but the earthworks for it and the connection as well as the pump and piping also belong to that.
Then the walls... Are they only up to and including the gypsum plasterboards? Do you want to put wallpaper directly on it, or plaster/prime/sand/...? Are you laying the floorboards yourselves? What about the tiles in the wet rooms? I don’t read anything about a staircase... Is it included? Assembly too? Do you have delivery costs for the kit?
I’m sure I’ll think of more... But since we are currently also planning with a kit, we are pretty well versed in the subject... Sorry for the wall of text - was more of a brainstorming!
