# Mortar type for limestone foundation repair



## dielectricunion (Feb 27, 2013)

I'm relaying a small section (6-8' long X 24"- ish) of an old limestone foundation under a 100+ year old house.

It's not so historically pristine that I have to worry about matching the exact mortar, especially since most of it will be near or below grade.

I assume I should not be using a type S mortar mix. Would there be any reason to use a lime mortar, or should I just use a weaker cement based mix?

This is zone 5, south/central Indiana.


Sent from my iPhone using Tapatalk


----------



## superseal (Feb 4, 2009)

Just throw some horsehair together with some clay mud, lime and wicked coarse sand :laughing:

Just be sure you waterproof the exterior :thumbup:


----------



## Fouthgeneration (Jan 7, 2014)

I'd consider installing a water proof/vapour barrier layer of material,(such as asphalted copper foil or 40 mill PVC flashing where ever the earth touches your foundation... Thus keeping the stone wall much dryer and lowering the average humidity in the cellar/crawl space.

If your joints are large use mostly concrete sand for aggregate instead of masonry sand, this will also reduce the demand for lime and cement % for the courser mix. If desired, you could point the joints later with a fine sand mix, 

I'd secure some replacement stones that kind of match to replace any frost damaged unusable original units, You could cheat and hide various pieces of modern masonry behind the old crap to achieve the original size and volume:thumbsup:

Don't forget the electrical conduits and boxes....


----------



## JBM (Mar 31, 2011)

Id maybe use a white portland/lime mix and mix it 2.5/1


----------

