I purchased my 110 year old colonial house 6 months ago. It has a field stone foundation that looks completely original (with a few small repairs). The house is located in North Eastern Massachusetts and is exposed to the worst of the elements around here. This has lead to the walls of the foundation starting to crumble, the mortar is loose on most of the wall and unstable. I can peel pieces off with my fingers. When I "knock" on the joints it almost sounds hollow. this is widespread throughout the basement. However the walls seem solid enough.

My question... I want to sure up these walls. I want to get a more water/rodent tight perimeter.

  • What are the steps I need to take?
  • How much of the old mortar should I remove? if I removed all of the "loose stuff" it seems like this project would take months! years even!
  • What kind of mortar can I use as a replacement? I read online that its bad to use Portland cement? Best to use Type N Lime mortar?
  • What tools will I need?
  • Is this a do-it-yourself job? or should I hire someone?

thanks for any info... getting really nervous about this project!

  • How many linear feet of foundation are we talking? How tall?
    – longneck
    Sep 26, 2013 at 15:49
  • Have you gotten an estimate from a contractor yet? That's the first thing I would do.
    – longneck
    Sep 26, 2013 at 15:50

1 Answer 1


I have recently researched this for my granite foundation. There's quite a lot of info on the internet on this topic, but here's what I can answer based on my experience:

You will only need the most basic tools: a throwel, joint filler and somewhere to mix the mortar. I also recommend getting masonry hawk to hold the mortar while you are repointing

This can easily be a DIY project as there's nothing complicated or requiring expensive tools. It will definitely take a long time. I usually work on my foundation just a few hours a week and there's still quite a lot left. The process is pretty tedious but I find it relaxing. It is probably best to work in small sections so you do not destabilize the whole foundation. I typically remove crumbling old mortar with the joint filler, vacuum the cavity, spray with water and fill it with the new mortar.

I think fieldstone is pretty soft, so even type N mortar might be too hard. You might want to look at type o or type k

If you decide to hire someone, I would make sure that they know and understand old masonry and techniques.

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