Comparability of costs Architect vs. General Contractor

Yes, then it is very likely due to the situation itself for the general contractor! Concrete stairs are either cast in place or, for simplicity, installed as prefabricated parts into the floor with a crane. No idea if the crane has to come for each floor. The general contractor will also have good conditions with the stair builder. For the concrete stairs, he would now have to commission a subcontractor, determine prices, and clarify logistics. And then there is the building construction, which may need to be adapted to the stairs. Decoupling from the stairs? I lack some expertise here, but all this can contribute to the price determination.

It is the same with our main contractors – every deviation from the standard costs an inexplicable surcharge. Another example is the door in anthracite instead of white, which is supposed to cost an additional €2,300 [U]. A white door with installation is already included in the construction service description – anthracite-colored doors do not necessarily cost more than white ones when you look around.

Such surcharges result from the purchasing policy of the general contractor. If they buy 10,000 white doors from door manufacturer X, they get them at price x. The larger the quantity and the simpler the color, the cheaper = more margin. If now 50 doors have to be ordered in anthracite, they are accordingly more expensive as a smaller quantity.

But not with a general contractor who builds 15-30 houses a year...

20 houses with 12 doors each are already 240... If he then wants to offer two or three types, he already reaches his 1000 doors...