Mortar for repointing old stone walls?

[Easy Livin’ 3000]

This is a great conversation. I was hoping for a quick easy answer, but as usual, that's not the right answer. I didn't even know there were different colors of sand, nor where to get such things. I do know I don't want light grey mortar joints, was just thinking I might add some brown pigment and lime to some pre-mix type N or O, whatever I can get at the box stores. More work to do figuring...

 

[Ashful]

Any masons’ supply (eg Landis Block) will have all of these ingredients.

 

[bholler]

Oh... got it. I wasn’t aware you could buy that pre-made.

Yup all kinds of different colors and strengths.

 

[Easy Livin’ 3000]

Great, I found 2 mason supply places reasonably close, and will stop by soon. I'll see if they have premix in a desirable color, type n or o and price it. If not, I'll get some either some straight Portland or type n cement, hydrated lime, brown sand (looks like it's referred to as "bar" sand), and mix it to the appropriate ratio, tbd. 9-2-1 is recommended on a masonry site (sand-lime-portland), but that seems pretty sandy. According to the web, mix no more than can be used in 2 hours. I already have the pastry bag, but will need a tuck pointing trowel.

Still have a few hours of demo and clean up (oh, the dust!), But, i hope to get busy putting things back together by next week. Deadline for completion is the first burning. We started in October last year.

 

[bholler]

Great, I found 2 mason supply places reasonably close, and will stop by soon. I'll see if they have premix in a desirable color, type n or o and price it. If not, I'll get some either some straight Portland or type n cement, hydrated lime, brown sand (looks like it's referred to as "bar" sand), and mix it to the appropriate ratio, tbd. 9-2-1 is recommended on a masonry site (sand-lime-portland), but that seems pretty sandy. According to the web, mix no more than can be used in 2 hours. I already have the pastry bag, but will need a tuck pointing trowel.

Still have a few hours of demo and clean up (oh, the dust!), But, i hope to get busy putting things back together by next week. Deadline for completion is the first burning. We started in October last year.

Just get type n or type o and dont mess with the lime and 3 to 1 which is what your 921 is is a pretty standard modern mix with type o i would do that type n go about 3.5 to 1

 

[Easy Livin’ 3000]

Just get type n or type o and dont mess with the lime and 3 to 1 which is what your 921 is is a pretty standard modern mix with type o i would do that type n go about 3.5 to 1

Ok, thanks! I think I just need to find the brown sand and I'll be ready to go. I was thinking this, but wasn't sure of the ratio if using o or n. Appreciate your help as always, bholler.

 

[Ashful]

Yeah, 3 to 1 is NOT sandy... 4 to 1 is not uncommon.

The ratio is called out as sand to Portland+lime. 9-2-1 is 3:1.

 

[bholler]

Something i didnt mention earlier but can be a big help is acrylic modifier. It extends working time increases bonding and really hrlps with workability. And if using a bag or pointing gun it is really necessary

 

[jharkin]

You got great advice from @Ashful ! I will add that when I bought my house (timber frame but a stone foundation) I also tried to go the full on conservationist route at first. Got a bag of lime, mixed up and aged my own putty. Its not difficult, but OMFG is it time consuming. I mixed it 3:1 with sand for interior basement repointing and its holding up pretty good even after 10 years.

Note that if you want to go this route you can get pre-made putty at places like https://limeworks.us/ or if you want to just use modern mortar but get the color matched (I agree with Ash thats OK on stone, but not on pre-1900 brick) then you can take a chunk of mortar to your local masonry supply and they usually have a display of various colored sands that can be mixed in to color match.

 

[bholler]

You got great advice from @Ashful ! I will add that when I bought my house (timber frame but a stone foundation) I also tried to go the full on conservationist route at first. Got a bag of lime, mixed up and aged my own putty. Its not difficult, but OMFG is it time consuming. I mixed it 3:1 with sand for interior basement repointing and its holding up pretty good even after 10 years.

Note that if you want to go this route you can get pre-made putty at places like https://limeworks.us/ or if you want to just use modern mortar but get the color matched (I agree with Ash thats OK on stone, but not on pre-1900 brick) then you can take a chunk of mortar to your local masonry supply and they usually have a display of various colored sands that can be mixed in to color match.

If you match the hardness of the old mortar there is absolutly no reason you can use modern mortar even on old soft brick.

You are right about color samples at some masonry supply places. Some have a good sample board with different color mortars mixed with different sands.