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1910 Stone Basement Wall Mortar Repair

My 1910 home has a stone foundation wall and a concrete floor with a french drain leading to a sump pump that removes most of the moisture. The walls don't leak when it rains.

But in some places the mortar is crumbling...even to the point of being dust. In other spots, a previous owner put what looks to be cement in place of mortar.

I'm planning on finishing a section of the basement for the kids, and want to replace the crumbling mortar in a few places to reduce dust. Can I do this myself, or should I hire a professional? If myself, what needs to be done? If pro, what kind of pro would I hire? A stone mason?

Guy H
Re: 1910 Stone Basement Wall Mortar Repair

I am facing the very same issue and came to TOH for suggestions. However, I have already logged an hour+ hunting for info on the web. I'm convinced for the need to clear-out the crumbling mortar and tuckpoint the joints. There are a number of coating products I've found on the web--Dry-Lok waterproofing paint or Xypex(which forms a crystaline coating, bonds with the wall I guess). I might also consider parging afterwards to create a smooth finish. I know from exp. that tuckpointing is a grueling chore, but it seems to be a must when facing crumbing mortar.

I tuckpointed the exterior foundation a few years ago and it was a tough, tough job. Yet, I plan to do the work myself but know from experience this will require much endurance and patience! If I had the extra $$$ I'd definitely have someone else do this--general construction folks, masons, maybe basement waterproffing people should be able to handle such a job.

Re: 1910 Stone Basement Wall Mortar Repair

I faced the same issue a while ago and also spent a long time looking on the web for waterproofing solutions for my old fieldstone and cinder block basement. Eventually what I did after much research was (i) chisel out all the old and LOOSE mortar between the field stones in the basement walls and then vacuum out ALL the dust and minor debris - use a ShopVac if you can buy/hire one. Careful doing this though so as not to dislodge the stones or intact mortar, (ii) purchase 3 or 4 bagss of pre-mixed 'mason's mix' or 'mortar' from home depot or any local building/masonry supply store - should be about 6 dollars a bag and also buy a small pointed masonry trowel and a large flat masonry trowel, (iii) use both trowels to apply the mortar between the stones and overlaping the stones the mortar sits on the flat trowel whilst you scrape it onto the wall using the small pointed trowel. then use a damp old paintbrush to smooth off the mortar. Its quite easy to do - I have no DIY skills and managed okay. As for waterproofing I also looked at (and purchased) the Xypex product. However, whilst this is great for chemically waterproofing CONCRETE (by reacting the molecular structure of the concrete as I understand it) I would not recommend it for waterproofing recently mortared fieldstone foundations or cinder block as neither of these are concrete so one is not quite sure the chemical reaction will work. Instead I would suggest using the sanitred products - www.sanitred.com - as waterproofing as these can be used on stone foundations (with mortar in between), concrete block, cinder or concrete. Sanitred works by forming a rubberized seal - physically clogging the cracks, gaps and pores in your wall. You can see my response to a question on the topic of Sanitred on page 2 of the basements forum on this website. I hope this helps. My basement is quite dry after the combination of the re-mortaring and application of the sanited products and my DIY skills are pretty much zero. Be careful to follow the sanitred instructions exactly and fill EVERY pore and crack with the sealant for it to work though (experience from much trial and error!)

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