When it comes to installing a concrete foundation, layout tasks will be required of the crew excavating for the foundation, the crew laying out the footer, and the crew laying out the foundation walls. Each phase of layout is important, but the need for accuracy increases with each phase of layout.
The layout task of the excavation crew will be to establish where on the site the foundation will go and where the corners of the foundation will be located. Typically 5’ offset stakes are installed at each corner and sometimes in between corners for long wall runs. Also it is common for the ground to be spray painted in the actual location of the future foundation wall so the excavating crew knows exactly where to dig. Often on the stakes will be written the depth that the excavating crew will need to cut from the existing grade elevation to reach the bottom of the footer elevation. It’s also important to note that depending on the depth, the excavation crew will excavate a certain distance past the outside of the proposed foundation wall, to allow the foundation crews room to work.
Then it will be the concrete footer crew’s responsibility to layout the footer. This task is increasingly important because the foundation wall will rest on the footer and requires a certain minimum footer width on either side to be structurally sound. Without this the footer will need to be removed and replaced back to the areas where it strayed from accuracy, which is never an easy or inexpensive task.
Lastly, the foundation wall crew will need to layout the wall forms on top of the footer to within inches (or less) of accuracy. The entire structure above will rest on these walls and the dimensions of the building have been pre-ordained to meet code requirements and building owner/architect’s designs. Any inaccuracy will create issues in terms of building wall layout/installation and will only snowball in terms issues with other construction trades within and outside of the building.