I have talked to 3 local people and have had 3 different answers, and am trying to find some more input or some clue to help me determine which way to go. I have an old, but not historic, home. The problem is a circa 1850 (or earlier) foundation wall in need of repair. The three opinions are: 1) it is absolutely necessary to analyze the mortar and use a precise mix to match or the bricks will be destroyed (contractor with experience in historic restoration). 2) it is okay to use a pre-mixed mortar with additional lime added to soften it (mason who has been 'repairing walls like these for 30 years and never had a problem'). 3) using pre-mixed from the store is fine. Anything else is a waste of time and money (retired contractor who is a friend--although this seems the least likely choice to me). So, in trying to figure out what to do, I've done lots of reading. Most on-line and library materials discuss brick homes, not brick foundations. The focus on mortar analysis (opinion #1) seems to be more about what sand was used so that the coloring will match for historic restoration on brick homes as opposed to simply the proportions of lime/sand/cement (if any) in the mortar. The articles focus on appearance issues from not using the right sand mix, although they do stress not using mix with Portland Cement on old brick. Very little, if any, of this repair that needs done is external, so I am not concerned about finding the right sand for a color match. Does anyone know (or can point me to a resource) about mortar analysis in terms of getting the mix exact? How critical is it to get the mix of lime/sand/cement precisely the same as the old mortar? There is discussion of the bricks being destroyed by using a mortar with portland cement, and I'm unclear if using a pre-mix with additional lime might result in a crumbling foundation in the future. (Is portland cement the only kind of cement used in mortar or are there multiple types?) The mason (opinion 2) thinks that brick destruction is more an issue with an external house wall that faces temperature extremes, not a foundation wall that is largely underground. I would appreciate any additional information/insight anyone on this site might have.