100 year old stone foundation repair

12 Replies

I have acquired my 3rd Buy and Hold property which will require more work then needed in my previous two.  I'm going to leave this post just to the foundation.  A little about the home.  It was built in 1910 and is a semi detached (I guess you would call it, one side of the house shares a wall with neighbor) 3 bed room 2 bath city home in Little Italy Wilmington, DE.  I love the place as there's a ton of upside, I just have to get there.  Starting with the stone foundation I noticed the mortar is missing/crumbling in some areas.  I can see a tan/brown sand underneath where the mortar was.  When you touch it the sand material falls right out.  I know that you need to remove all the old mortar but how far into the joints do you go to remove that sandish material?  Do I put backer rod in there?  I have the ability to do this and just want to make sure I'm doing it right.  I have attached pictures of an example area and greatly appreciate any info what so ever.  Also interested in hearing opinions on what mortar type to use.  I've read anything from type S, custom lime mortar mixes, to getting your mortar tested.  


General view of my foundation/brick wall.  There is a sidewalk that meets the stone foundation.

The brownish area in the center of the photo is a small problem area. 

Josh, I can't see all of your posts text for some reason but that foundation looks to be in pretty great shape man. It appears to be dry and plumb. Which means you have good drainage and no water penetration on the exterior. The mortar is in pretty good shape and I would not recommend repointing the stone with new mortar. if anything just run a skim parge coat over it to smooth it out and if you're really worried, seal the parge cost with drylock. Make sure your gutters are working and that your driveway / lawn is pitched away from the foundation and you'll have a long time left on this wall . If there was a question that I missed, tell me below, I think maybe the photos messed with the formatting as I am on the BP mobile app
Just seen your post in full. The mortar will always flake off like that, puts skim coat on it and you'll be fine. The foundation is in good shape.
The white on the redbrick is a sign of moisture though. if this is interior then I would recommend the drylock and perhaps a dehumidifier. though you could ignore this for 20 years and be fine.

OMG when I was reading your post I thought 💯 issue must be very big but it’s is normal maintenance fix!

@Ronald Starusnak , Thanks for the reply I have taken a couple more photos since it is daylight outside.  I'm interested to hear more about the whiteness on the brick.  This is an exterior wall btw but does not get much sunlight during the day as my neighbors house is 4-5ft away.  Two of these photos show the up close problem areas where you can stick your fingers/hand all the way in there.  Apologies for the photos uploading sideways. 

Josh, with the flaki-ness of the mortar. I'd say you're right that it is a limestone base but you can just stuff the hole full and you'll be fine. That is a common repair we do. When we do new siding and windows on a house, we offer to fix the foundation and it only takes a few minutes. The whiteness on the brick is called efflorescence and but it isn't necessarily a bad thing, mostly just a cosmetic annoyance. It's essentially just salt, but it is indicative of water penetrating your brick. When that house was build, they intentionally did not use the red brick all the way down, typically because when water splashes the ground it causes wearing of the mortar just like what you're seeing. So they typically use a stone that is less prone to wear. 

I can see what looks like a gutter running down and stopping at the lower foundation. This gutter is sending water to the concrete below which is splashing back onto your mortar and causing premature wear on both the foundation and the concrete. 

Thank you @Ronald Starusnak for the great info.  Very much appreciated.  You're correct about the gutter/down spout.  Here in the City of Wilmington the rain water waste ties right into the home waste.  The drains on the outside of the house go in the basement and tie into the home waste drains and it all goes into sewer.  In the picture where you can see the gutter/white down spout, that at one time would tie into the cast iron (guessing its cast) pipe hidden in the picture behind the white down spout.  My last and final question, (again thank you for this information) if the cast iron drain going into the house has been closed off, and is why they have that white flex tube running slightly away from the foundation, whats the best way to get that gutter drain running away from the house?  Note the public side walk is right there so i cant just run a 8 ft piece of plastic drain pipe away from house.   

@Joshua Maisel - All of my rentals are in Wilmington, DE and they're pretty much all pre-1935. They all have this issue in the basement. And what @Ronald Starusnak said is exactly what we do. You just knock out all the stuff that has dried and flaked away...or is easily able to be knocked loose with a mallet...and then you go back over top of it filling in the gaps. If you manage to get a dry basement in Wilmington from one of these older homes that's impressive. Cracks me up when I see flippers trying to put finished basements into Wilmington row homes. Buyers think it looks great...but they're just destined to have to gut the place in a few years once the water finds its way in again. 

Hey Josh, I would try to run that gutter perhaps into a PVC pipe that drains into a sub pump in the basement. Does this home have an old french drain that goes into a sump hole? 

@Ronald Starusnak No it does not have a sump or old french drain.  I have gotten suggestions to run a new pvc pipe/drain through the basement window opening and seal it up.  This is suggested instead of putting a new hole through that stone foundation.  The existing drain that the gutter down spout should connect to runs into the basement but is filled with concrete (not me) from the outside for some reason(it was prob leaking somewhere).  I'm understanding that my basement moisture issue is due to a few things.  As you said, that gutter water pouring down there doesn't help.  I'm not looking to fully finish the basement but rather ensure the house is solid for as long as I am....I'm 30 so she should match me another 40 or so hah.... Here is the view from the basement inside...  

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