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hack of all trades
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Discussion Starter · #1 ·
Does anyone have a recommended ratio for mixing mortar to repoint limestone in zone 5 (Indiana). I'm not sure yet what the existing mortar composition is but I think the guy I'm helping is planning to use type S. I know type S is a poor choice so I'd like to find something more suitable.
 

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What sort of stone is it. i know limestone but any idea where or what quarry? You're in Indiana so i'm guessing it's the typical indiana limestone? grade of the stone isn't too important but is it above grade, below grade...mass masonry, veneer, thin veneer? Interior or exterior?

Generally a type N is fine for exterior non load bearing applications. type S is a structural mortar intended for load bearing material. Indiana Limestone is a good sound material that should do just fine with a type N although a slightly weaker mortar wouldn't be bad. If the existing mortar is softer than a type N however you should match it as best you can. A good rule is that if you have different hardnesses/permeabilities of mortar, the softest and most permeable should be on the outside and the hardest/least permeable should be on the inside

here's some reading http://www.bybeestone.com/pdf/ili/22nd_Edition_Handbook.pdf
 

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The advice dom-mas gave you is very sound.Knowing Indiana well (live in it) Bloomington and Bedford are the absolute epic centers for Indiana Limestone. Follow dom-mas advice and you will be fine.
 

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Virginia limeworks makes a 500 and 750 psi mortar. It would be similar to the type N without the evaporation issues if the building is made with lime mortars.
 

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If you actually read the ASTM standards for mortars, there is a recommendation (Appendix 1?) that says to use the weakest mortar possible to carry the loads that exist. It is a recommendation that reflects the basis of that ASTM standard that there are other properties more important for masonry than the compressive strength.

For stone, you have a full mortar bed in a very thin layer almost anything would be acceptable as long as it is workable/practical since any loads would be low. The strength of mortar is determined in a 2x2x2" cube that shows much lower strength than what it actually shows in use.

I have seen 8" hollow, 2 block high hollow prisms made with 2000 psi mortar that tested at over 4800 psi as an example of the effect of mortar structurally.
 

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Can a 2 story brick veneer be considered structural for type "s" ? There is much weight there. Or is type "s" mostly a residential foundation material. Type "m" is going to be commercial foundations of larger structures correct?
 

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I saw a complex of about 15 apartment buildings that were between 12 and 20 stories that used one one type of mortar for all masonry. The buildings were load bearing 6" thick partially reinforced block for ALL walls and there were no steel or concrete walls or columns. They used Type S even for non-bearing walls because it was easier to use one type of mortar everywhere and avoid any errors. Type M was not even considered and the engineer even had a limit on the maximum strength of the grout used/allowed where the walls were partially grouted. There were no solid grouted walls.

There is always the classic question of "Does mortar keep block apart or hold then together?".

This project was in Brazil, but according to the U.S. masonry codes and standards, but it was light years ahead of North America and Europe in masonry design and construction. There were no clean-outs since they randomly used a TV camera on a cord for inspection and all block were tested/sampled/approved before shipping to the project. Special shape 6" block were used with open ends and 2 webs spaced 8" on center for perfect core alignment. The block had 1" face shells.
 

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Everyone ahead of me is dead on. I would use type N butmake sure you don't rake the joint back to far. Alot of the houses around here, especially with brick work, have a 1/2" deep flat raked joint. I have noticed that it tends to hold the water and we do alot of grinding then re-tuck pointing joints that really are not that old. And I'm not even talking about some of the bricks that the face is breaking off.
 

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hack of all trades
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Discussion Starter · #14 ·
The mortar almost looks like sand mix concrete, it's harder than the stone for sure and chimney cap is made of same material. These guys have it all caulked up and said they were getting water in the house. I'll probably refer them to a more experienced masonry crew. I'm more of a handyman carpenter.
 

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Where is the cricket? 6' plus of snow drift, well over flashing,= leaks in winter.

Cap should hang over stone 3/4-2" with a drip edge, missing soft joints around flues = cracked/leaking at every flue.

Demo the cap, and the rubble stone,layout new cricket, flash(100%cover the backup wythe with continuous flashing to the new cap. Replace any damaged flues, flash under new poured and tinned cap or just tin cap the top...to cheap out. Fix the chimney, then install the cricket/new shingles.

Seal EVERY stone anchor at flashing penetration,weeps and drainage screen in cavity.

Don't build chimneys out of rubble. pretty but high maintenance.

Pointing is for walls that haven't fallen apart, this has.
 
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hack of all trades
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Discussion Starter · #16 ·
The cap is actually recessed with no drip edge and there's no weep on this facade. Cap has no sort of control joints and is cracking across several places. I'll let them know they're going to need to call a proper mason to rebuild this thing.
 

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Take that down to the roof and put a brick one up. I can't believe there is no cricket on that mess.
 

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oh geez. that thing is so far from what i was thinking when read limestone and saw you were from indiana. Looks like sandstone to me but who knows. There is nothing right about that. No cricket/saddle, terrible crown, bad jointing, awful workmanship...the list goes on and on, i'm very skeptical about that thing being at the proper height also
 

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Discussion Starter · #19 ·
When I originally said limestone, I hadn't seen this house and the guy who looked at the job called it "brown county stone", which... what the hell is that. So i assumed limestone or something similar. Apparently the HO's hired someone to patch it up and they randomly squeezed 3 or 4 completely different types of sealants around the various cracks and holes. I thought the husband went up there and did that crap. I think it is sandstone. It's incredibly soft and I can carve into most pieces fairly easily with a screwdriver or chisel. The mortar is extremely hard. these are sort of veneer stones but theyre not even attached to anything. Inside are clay flues but in between the two seems to be hollow. Roof is also a little soft near the perimeter of this thing.
 
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