We have an 1890 historic Victorian that has a red brick foundation. Many mortar joints were loosened by the flooding from Hurricane Sandy. I hired a mason who has raked and cleaned the mortar and it is prepped for repointing. The question is what to use?

From what I have researched it seems that type N would be the best fit. The home is located 3 blocks from the ocean and has about a 3 ft crawl space. It doesn't appear that the brick has ever been repointed before and it is in generally good condition. They are structural walls and the exterior is covered by a wrap around porch. I also read that type O would be a good fit but it doesn't seem right for structural walls.

I have read varying opinions with regard to the type of mortar that may currently exist. Some say that homes between 1890 to 1930 would likely contain a mix of lime, sand and Portland concrete. Others have said that Portland may not have been readily used until later. Evidence suggests the home was built between 1885 to 1895. The fact that much of the mortar is still in great shape and is still relatively hard makes me think that it was not just a lime/sand mortar and that there was Portland added to the sand and lime. Is there any way of knowing without extensive testing as to mortar type?

The foundation is not visible from the outside so I am not concerned about the appearance as much as the structural integrity. Thanks for any input.