Terry's Tips are personal observations based on my experience and seeing the cause and effects of things. There may be many ways to address different problems and all opinions are welcome. I am always open to suggestions and certainly want you to correct me on any mistakes that might be written.
If you look and listen to your house, it will talk to you. Are you listening?
Here we see a galvanic reation taking place which is causing the corrosion. The large headed nails appear to be electroplated roofing nails instead of the hot dip galvinized 10d nails used on the joist. You can clearly see the performance difference. Roofing nails do not provide the proper shear strength to be used in joist hangers anyway. This is a safety concern on both fronts and replacement is needed. With today's ACQ lumber it is highly recommended to only use hot dip galvinized fasteners or better yet stainless steel.