No earthworks, electrical work, and water etc. have been carried out by other companies, the roof (timber frame) is on, covered, windows are installed (another company) heating etc. as well...
Offer binding, what did you sign? What was agreed when and how, or what was changed after the offer was submitted? If the final price is now 10% more expensive, there must be reasons for that. Compare the offer and the final invoice and you have your result.
Initially, 90% of the final invoice was expected from you...
I do not yet know the reasons, I have just now the invoice in my hand. Comparison shows that there are differences in skilled labor hours and some material costs. Therefore, I wonder whether 10% might be normal, not worth the stress, etc.
Depends
More material can also mean more time
Why more material?
Only 150 sqm requested and 200 sqm installed
Additional sampling on request. You if we do it this way then
Or price increases
Does the offer have clauses or does the cost estimate override everything