Fieldstone Foundation Re-Pointing 101.....Need Advice!!!

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Old 11-16-10, 07:06 PM
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Fieldstone Foundation Re-Pointing 101.....Need Advice!!!

Okay, first let me say I am a masonry newbie. I've avoided re-pointing my 110 year old fieldstone foundation because.....well....I hate playing with concrete or mortar. I'm not a complete moron....I've patched my share of concrete and made a small pad for my grill

So anywho...here is what I'm working with.....

The worst of it.


Typical for the rest of the 18x35 basement walls. The existing mortar is very crumbly below grade. The mortar itself seems to resemble horsehair plaster - yes it has hair in it!


So I get a few bags of Quikrete Type S Mortar and mix it to the consistancy of Play-Doh. I grabbed my pointing trowel, a metal spatula and go to town....

EPIC FAIL!!!! I'm sure my method and/or my tool selection was improper but it went horribly bad! More mortar ended up on the floor than it did between the fieldstones! It took absolutely forever to cover a couple square feet! I feel like I would have had an easier time making a little dryer of a mix... making a softball size ball with my hands and jamming it between the stones....and using my fingers to smooth it out.

What is the proper method and tools for repointing a fieldstone foundation??? Sure, it would be nice to hire a pro but the finances are tight and I'm flying solo on this one.

Any advice?!??!
 
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Old 11-17-10, 04:31 AM
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Try mixing it a little looser and use a grout bag to squeeze it into the joints. Then you can use a pointing trowel to finish it and poke in a little. Glad it is in good enough shape for you to do that rather than replacing it. Oh, the hair was used loooong time ago to strengthen mortars. Similar to what we do with fiberglas fibers in a concrete pour. Different times.....different materials.
 
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Old 11-17-10, 05:47 AM
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Thanks for the advice! I'll have to pick up some grout bags this afternoon and give it a try.... Do they sell these at HD/Lowe's or should I look somewhere specific?

My wife is pretty good at baking......maybe I'll enlist her help

**edit** nevermind...they do.
 

Last edited by BigOldXJ; 11-17-10 at 08:19 AM.
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Old 11-17-10, 06:19 AM
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The first thing you need to do is remove anything you put in the joints. Break it right out and start over doing it correctly with the correct product.

If you continue, you are effectively destroying your foundation.

Your foundation was laid with a lime mortar. It is soft and breathable, and as evidenced by it's age, very suitable for it's use.

You need to repair it with the same or a similar material, NOT a portland mortar, which is too hard and does not breathe. It will trap moisture behind it and dissolve the remaining lime mortar in a short amount of time.

I will post later on how to do it, or you can do an advanced search on this board for "lime mortar" and "tuckpointing" as I am sure I have asnwered this same question multiple times.
 
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Old 11-17-10, 06:45 AM
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This is what happens you you do what you are doing.
 
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Old 11-17-10, 07:12 AM
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The section that I did last night, probably 1'x2' was on the basement bulkhead walkout. It is newer and definetely doesn't have lime mortar. In most cases....just dirt. Eventually I'll be ripping it out and going with concrete block. For now I just wanted to tighten it up and make it more difficult for the mices to get in! It is also going to be my practice run from the rest of the foundation....

Thanks for chiming in Tscarborough. I did a quick search and your name came up on many forums and posts. I've read through many many topics and discussions along with "this old house" type articles and feel that I grasp the fundamentals now.

I still have a few questions though. The way my foundation is set up is that the above grade section is brick (in very good condition), and below grade it is stone. The original builders did not care about cosmetics as the stones are of very random size (some are even boulders) and the gaps between many stones can be quite large (big enough to put your arm through). The previous owners didn't care either as thier are many poor repairs and many layers of paint on the stone/brick.

1. On the mortar joints that are completely deteriorated: If I remove the majority of the old lime mortar, can I then replace that section with a portland cement based mortar?

2. Does anyone make a "just add water" lime mortar mix?

3. Is making a "lime putty" a necessity? Or can I just add the appropriate parts lime and sand?

Thanks again guys!
 

Last edited by BigOldXJ; 11-17-10 at 08:16 AM.
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Old 11-17-10, 04:15 PM
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You do not have to make lime putty, you just have to hydrate Type S lime for a couple of three days, then mix it with sand at 1 lime 3 sand. Put the dry lime in a 5gl bucket, 3/4 full, then fill the bucket slowly with water. No need to stir, you don't want to in fact. Just let it soak and keep the lime covered with water. After 2 or 3 days, pour off excess water and use the lime. Keep the water to cover what you don't use and it will keep forever so long as you keep it covered with water.

Unless you are re-laying the stone, you should not use the portland mortar. You CAN, however, add portland up to 10% (by volume) of the lime (5% would be my max) to gauge (achieve a faster set) the mortar.

Work in small areas, no hurry, so you don't bring the house down.
 
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Old 11-18-10, 07:55 AM
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Thanks for the help Tscarborough. A couple more probably dumb questions.....

1. Do the HD/Lowes type stores carry Type S dry lime?

2. Also, if I were to paint the stone/brick basement walls someday....will the paint breath enough as to not further destroy any mortar?
 
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Old 11-18-10, 09:57 AM
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None of them do around here, but they may there. It will be plainly labeled as "Type S", if not it is not the correct type. Masonry supply houses, block/brick companies, etc.

If you use a breathable paint, sure. You would probably want to stucco it with lime plaster first to smooth it out though.
 
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Old 05-13-11, 12:07 AM
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Going off of the stories above, I must say I'm a little scared!
Anyway, I have a very large 3 family (In Boston, MA/100 Yrs Old ??) I must re-point and seal interior of field stone foundation!
HELP!! House situated at the top of a hill, so the front portion of the foundation is buried underground up to the windows. This section has the most loose mortar. The exterior ground tapers down towards the back thus, the rear of the foundation is more exposed from the ground. The rear is no where as bad as the front!
So, can anyone advice me as to how and what to do to re-point and seal my old field stone foundation?
 
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Old 06-19-11, 11:20 PM
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I copied and pasted the image from BigOldXJ above because it looks exactly like some portions of my basement walls.

My name is Rob and I have an old 3 family in Boston, Mass with a huge full basement that has a fieldstone foundation in need of repointing. I can't afford to pay a pro to do it, so I'm on my own. I'm looking for some professional advice from anyone out there who has it? Like I said, the house is huge and old (Apprx. 100 Yrs). I've about S-Type mortar and such but I've never been given the full scoop...

Can Anyone Help Me?
Thanks.........
 
 

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