Mass determination of masonry, surcharge for cut-off

Hello everyone,

I have an offer from a construction contractor. Under the item Masonry, there is a quantity X in m³, which is multiplied by the m³ price for [Kalksandstein] and results in the total price for the masonry. So far, so good. However, when I go through the floor plan and add up the m³, I do not arrive at the quantity X. I have a total of 4 items for the masonry, which differ by 29%, 12%, 12%, and 10%.

I could imagine that some waste is factored in, either through the unit price or through the quantity. But 10% seems very high to me. I was thinking of 3% or at most 5%.

Is there anyone in the industry here or who has experience with how this is usually handled?

Does he expect that someone will ever check the calculations?....

Usually, the quantities are specified in the tender instead of leaving this to the supplier.

However, there was no tender. I went to the general contractor and gave him the floor plan as I envisioned it, and after several appointments, he prepared an offer.

I have a total of 4 positions for the masonry. they deviate by 29%, 12%, 12%, and 10%.

What are those four positions: exterior wall and interior walls 24 / 17.5 and 11.5 listed separately?

You might have mismeasured at two points: 1) Room height: here you overlooked the difference between "finished and raw room height" 2) Wall openings: here you deducted all of them, although some are "overmeasured."

I would have thought of 3% or a maximum of 5%.

I would not expect a higher proportion of the actual waste surcharge either.

Yes, there are 11.5 and 17.5 interior walls, 20 exterior walls, and a partition wall to the garage at 36.5. I used the raw dimensions, so not only from the finished floor. I think what you mean by measuring over is it. According to VOB, doors and windows under 2.5 sqm are not deducted. So I pay 4500€ for the windows and doors. In the upper floor, it is even more extreme. The 11.5 is used there. Doors make up almost 30% there. I will check that later to see if that is really the only reason. In Excel, it’s only a few clicks.