What type of material should I use to fill an expansion joint.

You can fill an expansion joint with silicone caulk, however it is recommended to use an elastic epoxy seam sealant after the grout is fully cured, such as Chockfast Expansion Joint material.

How do I seal expansion joints?

After the grout is cured, remove about a half inch of the expansion joint material and seal the top with an elastic epoxy seam sealant such as Chockfast Expansion Joint material.

Does the expansion joint need to extend into the concrete foundation?

The expansion joint is generally installed on top of the concrete foundation and below the base plate within the area where the epoxy grout will be poured.