Matching existing mortar - sandy consistency

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Old 05-08-19, 01:27 PM
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Matching existing mortar - sandy consistency

My house was built in 1959, and I'm working on some mortar issues, and would love to match the mortar originally used on the house. The mortar used from the big-box store is completely uniform gray, but the mortar on my house looks very sandy. Please see the attached picture. You can see where someone redid some brick back in 1985 when they took out a window and put in a door. The mortar looks completely different.

What can I do to get something that more closely resembles the original?

THANKS!
/b
 
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Old 05-08-19, 02:34 PM
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The premixed mortar uses white sand, it looks like your mortar was a coarse brown sand. Not sure if you can get sand to duplicate the coarse but using 3 parts brown sand and 1 part mortar should get you close to the right color.
 
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Old 05-08-19, 02:41 PM
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Thanks, one more question...
This is what the light colored stuff is (picture)... Are you saying add sand to that?
Or are you saying mix my own mortar (portland, etc)? - because I have no idea how to do that...
 
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Old 05-08-19, 02:53 PM
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The premixed mortar uses white sand - that is why it's grey. You need to use mortar [not premixed] and mix in 3 parts sand. That is basically what the premix is except you want to use brown sand instead of white sand. The mortar and sand measurements don't have to be exact. For small amounts you'd use 1 shovel full of mortar and 3 shovel fulls of sand .... or whatever amount works best for what you need. Portland is too strong, mortar is better.
 
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Old 05-08-19, 03:07 PM
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Man, I really appreciate your help. Could you give me the name of a product I should buy? I'm looking online at all the big box stores and trying to find "mortar" and I'm only seeing "Mortar Mix"... Sand I can find, it's the mortar I'm unsure about... Hate to bother you with this. Thanks!
 
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Old 05-08-19, 04:07 PM
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I cannot give you a specific product, but can say that Mark is right on. You may need to visit a yard rather than a big box, and you may need to play around with it a bit to figure how much brown sand you want to each unit of mortar, but it's doable.
 
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Old 05-09-19, 03:31 AM
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I never pay much attention to the brand. You should be able to buy it at a big box store along with any place that sells block or brick. Here is an example from Lowes - https://www.lowes.com/pd/Sakrete-70-...ement/50062541
 
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Old 05-09-19, 04:55 AM
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There are articles and videos online about matching mortar. I suggest you do some reading and watching. It's an art and depends on blending the right ingredients in the correct proportions. There is no formula and there is no "go buy this brand". You will be baking from scratch and will add ingredients and tweek until you get the desired result. You'll probably need portland cement or sandless mortar mix, lime and the proper sand. I once knew a mason who had about 20 different kinds of sand in his shed that he had collected over the years specifically for matching old mortars.
 
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Old 05-10-19, 09:25 AM
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Thank you all! I deeply appreciate the help. I'm just trying to get closer than what was done before, which really stands out.
I plan on buying a few types of sand, and the following (It says cement, but appears to be same as what was recommended):
https://www.homedepot.com/p/Quikrete...2570/100318484
 
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Old 05-10-19, 11:11 AM
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That mortar would have been a uniform tan for the first few decades, you're only seeing the sand color coming through because the surface mortar wears away over the decades (isn't a problem if the mortar is good.)


Your problem is that the 1959 mortar is (almost certainly) a custom mix made up in batches by whichever masons did the brickwork. Looks almost like beach sand and tan mortar. Good news is they would probably have bought local sand a few tons at a time, along with bags of lime. Other good news is that they likely used the classic (roman engineering manual of Vetruvius) mortar ration of 3 parts washed sand to 1 part slaked lime/ lime putty.

You will NOT match that color or texture starting with pre-made big-box-store concrete mixes. You actually do NOT want bix box store concrete mix, you likely want a "classic" sand-lime mortar mix.
I'd start by checking there are any "historic architecture tours" in your area, ask about matching old mortar.

Next lead would be checking the current list of local masonry contractors, and then checking against old phone books / old local newspapers to see which local masonry business has been around the longest. Call em up, tell him you're looking for somebody with enough experience to color match a 60 year old mortar recipe, offer to treat their oldest mason to a really nice lunch or early dinner if they can figure out what the mix is.
 
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Old 05-11-19, 02:59 AM
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Hal S is correct, that old mortar surface has been worn off after years of exposure. It's almost like a very small exposed aggregate surface like what's used in concrete flatwork. If it were mine, I'd buy a few cheap bricks and lay them up with your mortar experiments. Then, just like an exposed aggregate sidewalk, gently wash and lightly scrub the surface to expose the aggregate in the mortar. I'v never done it, but I really think it's worth a shot. Do some research on exposed aggregate concrete (without using a surface retarder) to see what the technique is when using just water.
 
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Old 05-11-19, 06:11 AM
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Those are standard "brush finished" mortar joints. (You use a long narrow brush to pack in and remove the excess mortar)

The OP can match the "exposed aggregate" look for a brushed joint by letting the mortar dry until damp, THEN dabbing/rinsing the damp mortar with a wet sponge to get the surface layer of lime off. This will create a light haze of mortar on the brick face, so after the mortar dries, you need to do a quick rinse with dilute muriatic acid to remove the haze, then wash down the wall with water to remove any leftover acid, the result is an expose aggregate joint.

If you need to touch up drips or splashes of mortar in a few places, just cut 8" circles from a cardboard box and use that like an abrasive wheel- cardboard is too soft to scratch normal brick, but just abrasive enough to remove a thin layer of mortar.
 

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Old 05-11-19, 07:12 PM
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I doubt if this is lime mortar but it could be a lime/white Portland mix or white masonry mix. Experiment, have fun. Try to get some samples of the different cements and lime if it is Portland cement just so you don't have a bunch of 70# and 94# and 50 # bags with only a little removed from them,
The advice to talk to old timers is good. Some will tell you more than you want to know and some will brush you off. Also if there is a firm that specializes in tuckpointing they know what you want to know but to do this yourself is hurting them. Masons on the other hand should not be threatened by someone pointing up a little mortar.
What does the mortar between bricks do? Does it hold the bricks together or hold them apart?
 
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Old 10-08-19, 07:46 AM
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I'm resurrecting this old thread because my mortar looks similar to the original poster. I need to repoint some bricks as well. I'm not worried about the texture because this is high up on the house, but am trying to get a similar color.

Does anyone have experience with adding dye to the premixed mortar?

My home was build in the 1930s for some background.

Thanks in advance!
 
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Old 10-08-19, 08:21 AM
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You can pick up dyes, liquid and powder at big box store (limited selections) as well as most concrete suppliers.

The problem is, concrete is very white when new but darkens with time, if you were to match color today it's going to still change with time so it's not an exact science!
 
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Old 10-08-19, 09:46 AM
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I DID use a dye mix with my mortar, IIRC, black, blue, red.
Got 2 different colors of sand, tan and grey IIRC

I got a 4x8 sheet of plywood and created a 4 x 4 grid for dye- none, black, blue, red as both X and Y axis (gives you 2 triangles of mixed colors)

Top grid was tan aggregatre, then did another 4x4 grid for grey aggregate.

I made a small batch of tan mortar, parceled it out into 16 dixie cups and added a drop of dye. (on the diagonals e.g. black-black, I used 2 drops). Repeat for grey mortar.

Let dry, top "triangle" shows what the mortar will look like now. Acid wash the bottom "triangle" to see what the mortar will look like when it weathers to show the color of the aggregate.
 
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Old 10-08-19, 10:13 AM
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When you add mortar color remember a little goes a long way. If you add dry color be sure to dry mix the material thoroughly. And don't add so much color that your dry mix look like the color you want. That will have way too much color. I used to match stucco finish to unknown stucco color and paint. I got good at it. It would take two or three days to get a match sometimes. Remember it has to set and dry. The other posts about aging and the process are right on, if you can understand Hal-S's process. I would weigh out 1/10 batches of stucco finish by weight then add small amounts of color to it then put a little on a wall or a board then add a little more color and do the same, etc. until I thought I was close. Write it down as you go.

All of this being said get close enough to suit yourself. It will probably not ever be exact.
And another thing, Is there actually color in your mortar or is it only a different shade of grey? There is some color variation in different brands of cement. And if you use white cement you get more pastel shades when you add color. Standard masonary cement takes color well. Once in a while strange things happen I had soe color I would swear was a brown color but it came out a nice shade of purple. Nice color but not what I wanted.
If you are in a large enough market you can buy colored masonary cement. It is used in the cement tile roofing industry to match the tile when they point up hips and ridges and the like.
 
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Old 10-23-19, 10:41 AM
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Thanks for the advice. Finished the project this weekend and it looks good enough. The spot I was repairing is higher up on the house and not very noticeable.

The dye I purchased was a small bag enough to treat 3 80 pound bags of mortar mix. That made it difficult when doing a small job. I weighed enough dye for one bag and then eyed it. Its not exact but doesn't stick out too much.

I tried to find pre-mixed colored mortar but couldn't find any in my area.
 
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