Question about masonry restoration

[HCJtractor]

My 100 year old brick house needs some mortar repair. I know the mortar is unlike the modern Portland cement based mortar, as it is much whiter and softer. I assume it's a lime based mortar common years ago, Having read lots about it, I want to experiment to try to match. I know I can get it analyzed, but I'm cheap. My problem is I can't find a type S hydrated lime. No one around here sells it, nor can I find it online. Quikrete makes this product I assume may be close enough, but it's not available here. Any ideas? Tractor supply sells an Ag lime some say is the same thing. Is that true? My resources tell me to use a hydrated lime.

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[Ed of all trades]

You will regret not using mortar. You can color it and it will match and last longer and also keep water out better. I helped do a pre Civil War farm house here in he valley a few years ago. We used 4.5" grinders with 3/8 wide diamond wheels and took out all of the mortar joints and tuck pointed them all back in. The dust and grit wire out the zipper on my carhartt coat. Ed

 

[chim]

"Some mortar repair" is difficult. There are many places where only a portion of the joints were done and it sticks out like a sore thumb. Although it would be a big job, repointing the whole building would normally look much better.

If I were to undertake such a project I'd seriously consider something like the tool in the link below. It's available for around $200 some places. Of course you'll probably wear out a few shop vacs that will be required to pull the dust away from the tool. But then, your lungs will be in better shape at the end of the project. OSHA has / is developing rules concerning silicates that will both help and handicap people who work with or even disturb masonry (repointing, drilling, cutting, grinding, etc.)

DWE46101 5"/ 6" Cutting & Tuckpointing Dust Shroud Tool Kit | DEWALT Tools

 

[HCJtractor]

I'm not repointing the house. Most of the joints look good. What I'm doing is moving a few doors and windows, so there will be some very small areas where new mortar is necessary. And from what I've seen and read, new mortar will not match the old, because it's a totally different composition. Most material detailing historic renovations also warn that using modern mortar with old soft brick can lead to issues, but that's not my main concern. I'm mainly concerned that my new patches won't stand out visually. That's why trying to use the original lime mortar formula seems wise. So I'm still looking for a source for hydrated lime.

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[Ed of all trades]

I'm not repointing the house. Most of the joints look good. What I'm doing is moving a few doors and windows, so there will be some very small areas where new mortar is necessary. And from what I've seen and read, new mortar will not match the old, because it's a totally different composition. Most material detailing historic renovations also warn that using modern mortar with old soft brick can lead to issues, but that's not my main concern. I'm mainly concerned that my new patches won't stand out visually. That's why trying to use the original lime mortar formula seems wise. So I'm still looking for a source for hydrated lime.

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Good luck but I doubt you will get the match you are looking for, you can't age what you are putting in. I hope I am wrong, but....... Ed

 

[KennyG]

I would try to color a current mortar mix to get close to the original appearance. "Back in the day" we would lay brick or tuckpoint with new mortar and then "dust" the brick and mortar with a dirty burlap sack to give it an aged appearance. Amazing how old it looked afterward. You might try experimenting with that approach.

 

[71bronco]

I've been a bricklayer for 35 yrs. What we usually use is regular mortar with a light buff coloring mixed with concrete sand(very coarse). Let it set up fairly hard and brush it with a stiff brush. if anything you want the new mortar a little darker than the old so it wont be as noticeable. This works on most of the old houses around this area

 

[PILOON]

LOL. I needed to repair some fireplace joints and matching became a challenge.
I ended up cleaning with a detergent and smearing the new joints with the soapy water until they all became the same color.
Nobody could ever detect the repairs.

Another thought is that latex based paints will adhere to mortar joints quite well so once done you can do the artist thing and actually paint the new joints to match. That would be my plan of attack.

 

[/pine]

Many times mortar was made with portland, sand and lime that lightened the color towards white...
A couple of options to making strong white mortar...

Trinity White Portland some "easy spread" and diamond sand etc..
Any exterior (colored "thin-set", tile etc.) mortar sets very hard with minimal shrinkage...
Look into using a masonry bonding agent....

Good Luck...

 

[OldMcDonald]

Quikrete makes Type-S hydrated lime, and other sorts of lime products. Ag lime is calcium carbonate, not the same thing, do not use it for mortars. Google Hydrated lime Type-S for more information on Type-S and some other manufacturers.

 

[tugboat-2]

. . . . yes I started to patch and point my 160 year old Canadian stone farmhouse many years ago, . just using regular store bought mortar mix which didn't match in colour. Before long I realized this job was much bigger than first thought. I hired a local expert who explained the absolute importance of finding and using the "original" 1856 mortar "recipe", . . for various reasons. The main one being for the same degree of expansion and contraction, . . especially in this often hot and more often extreme cold Canadian climate.

Eventually, after ripping out the old lath and plaster so I could insulate this cold house, I had to patch and point the "inside" of these two foot thick walls, . . I found lots of the original mortar had turned to dry powder and was falling away. I wondered just how much of my original store bought mortar-mix may have caused wrongful expansion and contraction and been responsible (in part at least) for this? (Lesson learned)!

I guess this portion of the topic has been well covered in the above replies, but felt I should include mine as it truly is important, . . especially where the climate can vary so drastically from summer to deep winter. Taking the easy way out, (as I did at first), can often result in substantial damage in later years.

. . CHEERS, and good luck,
. . . tug

 

[Cord]

You will regret not using mortar. You can color it and it will match and last longer and also keep water out better. I helped do a pre Civil War farm house here in he valley a few years ago. We used 4.5" grinders with 3/8 wide diamond wheels and took out all of the mortar joints and tuck pointed them all back in. The dust and grit wire out the zipper on my carhartt coat. Ed

This not necessarily true. Lime mortar is actually one of those things that they got right. Older bricks are often softer than the modern brick and as such require a softer mortar. Modern masons are using cement based mortars because the product sets up faster which allows them to set more courses in a day. Besides, the gray color is totally wrong. Also, do not use grinders on historic buildings as it's too easy to damage the bricks. Instead, use a mortar saw: AS170 Brick + Mortar Saw Yes, it's expensive, but maybe a professional tool house will let you rent it.

Menards carries a Type S Hydrated Lime which will work for your purposes. It took a little experimenting, but here's the mix design that gets pretty close to the mortar used in my 1880's home:

10 parts torpedo sand (coarser than masons sand)
3 parts type S lime
1 part white Portland cement (helps the mortar to "stick")

The mix in my house was pretty sandy so you can try reducing that amount if necessary. I'd suggest getting a couple of junk bricks and mixing up samples of mortar. I've also found that I need to pressure wash the mortar after a couple of months to help create the texture needed to match the existing weathered mortar. Lime mortars set very slow, so you must wait several months before washing it.

 

[dieselscout80]

Look up Carolina Eastern I know they have a store in Chester SC (803) 385-3117 and they sell Ag lime.