How to Build: Excavations (for Footings & Basements)


The excavation of footings or foundations for ICF structures is a very important step to an overall successful building experience. Maintain good communication with your backhoe operator to ensure that your ditch markings will be interpreted and dug properly. For instance, some operators like to use a center line as their basis, some an outer edge. Also, knowing what type of veneer will be used on the structure will help with ICF block placement over the width of the footing to be dug.

An example would be a 6” ICF wall: Total thickness 11” plus a brick ledge, another 6” to the outside of the form, and an additional 3” to the inside of the form for the floating slab to rest or be pinned to.

By taking into account these factors, you will obtain an accurate outside wall measurement on the footing and allow for placement of the form, avoiding structure shrinkage or expansion due to misplaced footings, which can be costly and time consuming to fix.

It also sets the stage for proper rebar placement at the footing first-course stage and for lateral support at the base of your ICF structure. This placement is of a crucial nature because of the webs in the forms. You ideally want the rebar in the center of the form and centered between the webs.

The optimal way to achieve this is a “Wet-Set” procedure. Depending on the type of construction used in your area, please review our construction details to match your building method.

Note: Inground footings are never perfectly straight. Also, please take this into account when you need a brick ledge or slab ledge as in the drawing above. If you don’t leave some extra width, there will be places which are not wide enough for these applications.

Enroll in BuildBlock’s free and online training course to learn how to install ICFs.

Excavation April 18, 2014