Digging around it is pretty impossible as the structure is all built up around it. I'm going to try contacting a firm that seals cracks in basement walls by injecting concrete in them. I don't know if it will work, but I'll call them and see what they think.
What started out as a simple job to replace the decking on my deck with composite boards has now become a much bigger job, as I discovered after removing the old decking that things were not level. Suspecting something was amiss, I pounded a rod next to the 4x4 uprights, only to discover that...