This is perhaps the most complex and expense part of the ADU construction. The concrete truck, pump and expertise was arranged by my builder Josh O’Duin.
The concrete truck was the type that customizes the mix on-site, It’s loaded with sand, gravel, cement, water, and additives and the operator selects the mix from a control panel. This reduces the risk of underestimating the quantity needed and eliminates wastage. It also means the builder can request changes to the mixture right up until the pour.
So my mix was 8.45 yards of 4000 PSI mix.
Here’s a video of the pour. It went smoothly although it meant a long day for Josh O’Duin. It was cool (actually great concreting weather) which meant it took a while to setup up enough that he was able to get on knee-boards and smooth the slab.
By the end of the day it was one fine, super-smooth slab of concrete.