Repointing brick or stone is not as simple as it sounds.
It is probable that masonry repair work performed by professional masons can not only damage, but destroy old homes.
You the homeowner and are responsible for protecting your home.
You must therefore be knowledgable on this subject and know what to ask.
Read on – this is extremely important. Let the buyer beware!
I feel like I should write all this in caps and bold, but I will refrain.
This brick needs to be repointed. Water can enter and freeze and destroy the entire wall if not repointed.
Your home may have wood shingles, but don’t forget about chimneys and foundation walls constructed with brick or stone. As time passes, the masonry on old homes eventually needs repair. The mortar holding the bricks or stone deteriorates. Cracks then form, allowing water to enter. If neglected, the freeze and thaw cycle will cause the bricks or stone to fall out and hit you on the head. To fix this you need to have your brick or stone Repointed.
Most of the best and well known masons out there may do a great job building a NEW brick wall, but you should use extreme caution when hiring them if you own an old home. When working with new brick, there is no problem, only the old brick and here’s why.
What is Considered “Old Brick”?
It is really difficult to know how your brick was fired or if your brick is soft or hard like brick sold today. In the late 1800’s through WWII some brick was fired similar to today’s hard brick. It depends on where you live and where the brick was made. Just because you live in a city on the east coast does not mean you have hard brick. You will be taking a dangerous bet with the odds in favor of the brick being softer. So – DO NOT TAKE ANY CHANCES!
Wheather your brick was made in 1900 or 1940, treat the brick as if it was from 1890! You cannot go wrong!
Repointing the Mortar can Severely Damage Brick & Stone!
Repointing brick or stone is a job that eventually needs to be performed to all brick and stone and should never be avoided. Repointing is a process where about 1 inch of old mortar is removed and replaced with new mortar. This is a very common practice and all masons do this. The problem lies in their knowledge of what type of mortar to use. Using the wrong type will cause irreversible damage.
Mortar used today is very strong and hard because it contains a large amount of Portland Cement. Portland Cement is good for certain applications, but it is not a fix-all as masons and building supply stores believe. Portland cement is not bad, it just must be used in the mortar mixture in a lower percentage when working with certain materials.
What Causes Portland Cement to Destroy your Brick and Stone.
- Moisture within a wall needs to escape and evaporate.
- This moisture must escape through the mortar.
- If the mortar that is too hard, that moisture is then forced to escape through the softer brick or stone.
- This will result in permanent damage such as cracking and spalling as in the image below.
Results of hard mortar or/and a water sealer. Repointing brick with strong hard mortar does not make a solid structure. Your brick is damaged beyond repair.
This is a photo of damage caused to bricks from using the wrong type of mortar. Using a Water Sealer creates the same problem. This can also occur with stone.
For Houses with Brick or Stone Built Before WWII:
1. The important thing to know is the mortar MUST be softer (in compression strength) than the brick or stone it surrounds and have greater vapor permeability.
2. The new mortar must also be softer than the mortar it is replacing when repointing brick or stone. This is accomplished by using less Portland Cement and more Lime and Sand.
Mortar Types for Repointing Brick and Stone. What you need to know:
Mortar comes is types. Type M, S, N, O, K, and L.
Type M is the strongest and hardest and contains the highest percentage of Portland Cement while Type L has no Portland Cement and is the softest. Type S, a hard mortar is most commonly used.
Type N, O and Type K are recommended for most historic masonry applications. However, masons are not aware of this. When hiring a mason, ask them what type they would recommend and see what they say – that is the test. Play dumb at first.
When I worked for the NJ Historic Trust, I worked on state grant funded projects for historic buildings. In most cases a sample of the old mortar was sent out to be analyzed to create a receipe in order to duplicate the content of lime and sand used to obtain a perfect color to match the old mortar. One such place is Limeworks .
For the homeowner this analysis is your best option. Another option for the homeowner is to scratch the mortar with a steel key. Do NOT use a key fob. If the key is able to make a scratch in the mortar then you know it is soft. In this case an NHL product – Natural Hydrolic Lime must be used. This basically means that the mortar mixture requires a higher lime content to soften it up. Type “O” is a strength should be safe to use.
If your fingernail can make a scratch mortar you would then need a softer mixture. This is all quite different from the usual S-Type used for hard brick or stone.
I recommend doing more reading or contacting Limeworks .
Fake shopping
Forget about Home Depot type stores. I wanted to ask the pros in the concrete, block, and sand business that specialize in masonry work.
I recently contacted Clayton Concrete Block & Sand (www.claytonco.com ) a very large company in NJ, and told them I had 150 year old brick that needed repointing. They recommended Type S. I played dumb and asked if it may be too hard for the old brick and asked if they carry Type O or K. I was told they are not familiar with those types!!!
I then phoned a different office and Type N was recommended and again this sales person was not aware of the softer mortar types. If I depended on the pro’s in the business for information, and repointed my basement foundation, 10 years later I may not have a foundation. Let the Buyer Beware!
Repointing brick with mortar harder than the brick. Moisture will escape through the softer brick damaging it while allowing only the mortar to remain.
The words of an honest mason
The following was posted in a LinkedIn forum discussion. Too bad those discussion groups are now gone.
How do we make all Masons aware that using Portland cement is ruining our historical Masonry! This is as big of a problem as one can possibly be.
We see all these historical society groups raising Hell about all different types of issues but nothing is said about the masons who go out into our cities everyday and open up a bag of Portland Mortar and start packing joints and ruining work that is over 100 years old. The question is how do we educate the Masons who don’t know anything about Restoration Masonry but call themselves Restoration Masons?
Forum Reply:
“I consider myself to be a Great Mason and I have 28 years of laying Brick and just up to 3 weeks ago i had no idea about the damage that i could do to historical Masonry if I used Mortar that we use today on masonry that was done before 1933. If I would not be the type of person that reads up and researches things before i do something’ I could have done the same as all the Masons I see do and been using Portland Mortar also.
THANK GOD FOR THIS SITE IT SAVED ME FROM POSSIBLY RUINING A PIECE OF HISTORY.”
I would love to take the credit but the site he references is the LinkedIn forum.
See what to do based on the age of your house.
https://thecraftsmanblog.com/lime-mortar-vs-portland-cement/
Preservation Brief #2 – Repointing Mortar Joints in Historic Masonry Buildings
Contact: https://www.limeworks.us
These guys are qualified by the state of NJ to work on grant funded projects. You really can’t get much better than that.
Thanks for sharing. I had my bricks repointed a couple years ago and I have no idea if they used they right kind of mortar. I didn’t know about this back then. I guess I’ll find out if my bricks start falling apart.
Actually, almost every mason may seem very knowledgeable about repairs. They wouldn’t be a mason for no reason. But thanks to this one, it is true that repairing old brick houses is a different thing. Unlike newer bricks that can be repaired in the simple and straightforward process. When it comes to old bricks, those older and more experienced masons have the advantage. They are more experience in older structures and have a better sense in choosing the right number of mortar for the old bricks.
It is not that old time masons were more knowledgeable about using softer mortar for old bricks, but a modern understanding of how old and new products and methods react with each other over a period of time.
This comment has been removed by a blog administrator.
I know this is an older article but I have been doing extensive research on this topic and issue for our house which was built in early 1950’s which used a lime and sand mortar for the brick. It was constructed between 53′ and 54′ when the use of Portland cement was gaining success due to the rapid demand of new homes. Portland cement was added to the standard lime/sand mortar ratio because of the quick cure time that Portland could achieve and the fast turnaround time of laying the brick and block walls of the structure. Hence a new way for a construction company to gain more profit by completing construction faster and building more homes to meet demand, just like construction companies of today switching to quick prefab wooden structures with an outer brick facia usually not even covering all sides of the home, usually just the front wall now! Portland has been used since the late 1800’s but its popularity in America didn’t grown until after World War Two when what was left of our our troops returned home from war. Even though our home is not historic the type and strength of brick used was is still softer than the bricks of today which are manufactured for a high Portland cement mortar mix.
I have found a very good company with a lot of information on this topic. They are located on the east coast and called Lancaster Limeworks of Pennsylvania. They have a nice website and they are able to take samples of your mortar and lead you in the right direction of what exactly was used in your mortar when it was mixed. They are very happy to take your phone calls as well. I’ve had to call them multiple times for help on our home projects. I hope this comment helps someone in the same situation.
Thank you Mike Roach, for the information on Lancaster Limeworks of Pennsylvania. I’m not very far from them. I’ve got to re-point bricks that are from the 1920’s. I have felt intuitively, that I better learn before I attempt it. I guess I’ll take some samples to them.
The owner of Lancaster Limeworks is awesome! I drive four hours each way to purchase materials from him!
I had my italianate
porch repointed 20 years ago not sure if the mortar is the right type but it seem to be ok and see no problems BUT THE COLOR IS HIDEOUS PLEASE TELL ME IF THERE IS SOMETHING THAT I CAN DO SHORT OF REPOINTING ALL OVER AGAIN.
Hi Mary – As for the right type of mortar, sit tight and keep your fingers crossed. Hopefully it will hold up.
As for the color, it would be a shame to repoint and do all that work over again. I don’t know if there is anything that could be done. Try a forum for masons. Wish I could help you.
There are masonry stains. I believe those repointing lines can be stained.
You can wash it with muriatic and mixed anywhere from 5 parts water to 1 Pate acid to 10 parts water to 1 part acid the stronger you make it the lighter your mortar will become I’m Tom if you have any questions I can be reached at+14014134730
Hi Ken, I Bought a house last year with exterior brick veneer and the mortar is falling apart in some places and there are many cracks along the walls with some cracked bricks. House was built in 1955. Brick seems to have a high sand content, and I’m not certain it is original to the house. There is no glazed face and to me it looks like the cheapest junk brick one could find, but I cannot afford to re-side or have it redone in brick. The brick are standard dimensions and not thin veneer brick. I’m going to attempt to re-point the damaged areas myself. I don’t see any weep holes at the bottom either, which I’m not sure whether or not there should be. Seems like the builder did everything on the cheap. I can salvage the veneer brick from my garage (going to re-side that part) for almost-new matching bricks of the same type. Any advice on mortar type? Thanks for any help.
Hi Kyle – For a 1955 brick you are probably ok since the brick is strong. I would contact Lime Works http://limeworks.us/home.php They can advise you better than anyone. Good luck!
My house was built in 1993 and there are some bricks with cracks all the way through that need to be replaced especially at a corner. Pintucking is also needed on other bricks. The brick mason came by and I asked the question of what type of mortar would be replacing what was taken out and his reply was “we use Portland”. Is this house old enough to be concerned about the type of mortar replacement; hard or softer than the bricks he replaces and the ones that do not need replaced?
Hi – you are safe with Portland.
That would be Tuckpointing, not Pintucking
I realize this is an old post, but my house was built in 1938. My brick was repointed 3 years ago with Portland, and now I have severe damage. The company that did the work is out of business. I’m in the process of figure out what to do next.
I would contact Limeworks listed above for advise.
If you can’t find any weep hole may be that the wall was not built with cavity gap between the wall. Most of the property to was built jut 13 inches tick with no gap. If that is the case. You don’t need to worry as that is the way they are. But if it is built with cavity and you can’t see any weeping holes. Just take a chisule and cut the out the vertical joint until you can see the holes is through the cavity and force in the weep holes @ every 4 bricks gap and that’s it. Some times the builders do forget to put the weep holes by mistake hope that will help you
Thanks
We have had repointing done by an individual we believed to be a competent historic mason, but I could tell on lower elevations that he had used too much Portland. This has been confirmed. Now we are having this mortar removed, but it is a very difficult job. Are there grinding tools that you would recommend for such a difficult job, hopefully something with a wetting element that reduces dust.
Sorry I’m just the messenger. Contact the pros at http://limeworks.us/home.php
No keep a blower in it or vacuum(interior) wet the bring and the mortor dust will sick to the brick face.
Pretty sweet article. A fountain of information on Tuckpointing.
Very well written article
This article is very helpful! We have a cream city brick home built in 1870. The bricks will need tuckpointing in the near future & it will be great to be armed with this information when we are looking for a mason.
For now, we are focusing on the limestone foundation which extends about 2 feet from the ground. I am hoping that this is something we can tackle on our own, but I’m not sure how to select a proper mortar. Do you have any suggestions?
Also, a neighbor told us that he prepped his foundation by removing all the loose mortar with a power washer (he doesn’t remember the type of mortar he used). Would you recommend this approach?
Thank you!
I am not an expert in mortar so I would suggest that you do contact the experts at Lime Works http://www.limeworks.us/home.php
These guys know what they’re doing.
First, thanks for this forum.
How can you tell if a 100-year old brick wall needs repointing? Our wall looks nice, but the mortar is soft (meaning it can easily be removed with a screwdriver). Is that normal because this is a “soft” old-style mortar, or is this a sign that the mortar has become “too” soft and must be replaced?
To my knowledge you will see the mortar missing between the bricks if you need repointing. Best to inquire with a pro in the link listed above.
I didn’t know that the hardness of the mortar that I use could damage the bricks. To repoint my house I would have just grabbed the cheapest mortar from the hardware store. So, I really appreciate your heads up. Perhaps this is a job I shouldn’t try to do myself! I want my masonry to last as long as possible.
The mason that I hired to repair the mortar on my stone veneer fireplace chimney dug the old vender block out and filled it in with mortar. Is this acceptable.
That is what repointing is but the question is what did he fill it with. That is what the usual problem is. There are many types of mortar.
Hi everyone-
We have a home built in 1951 in Chicago. We hired a masonry company to replace the flat garage roof and the first 5 rows of bricks. We thought we were doing it right but I think they used Portland Cement.
Now, 3 years later, all the bricks directly below the 5th row are crumbling. The cinderblock inside the garage is crumbling, too. We’d like to sell the house, is there a repair we can do first? I can’t believe we have to throw good money after bad. Is there anything we can do besides replace the brick all the way down the garage wall?
I would contact a lawyer. Don’t let them get away with this.
If you still having this problem call me on 07891724360 I can be of a help to you about the brick issue
Thanks
We bought our home a year ago. It was built in 1850 in central Virginia. We are only the third owners but the man who bought it from the original family used it as a rental for 30 years, doing only the cheapest repairs possible. The brick foundation and chimneys are covered in many layers of thick red paint. Recently, we have noticed large pieces of paint falling off with layers of brick attached. Is this because of improper mortar? Should the paint be removed? There is mortar coming out everywhere. We do not know who to trust. We want to take care of this house and get it back into the best condition possible. Any guidance would be greatly appreciated!
Good question – contact http://www.limeworks.us/home.php
An important step toward a successful repointing job is to secure a qualified and experienced repointing craftsman. An individual who is an excellent mason/bricklayer may not be a good repointer.
You did a good job covering some extremely important fundamentals about brick preservastion that most people dont know in this article. I am a proffesional mason and have been dealing with this for many years now. The best solution I have found is to grind out the joints using a grinder. Dewalt makes a cool grinder specificaly for it that comes with a dust collection shroud that you plug a grinder into. I use a six inch sandwich wheel so I can go as deep as possible. Then I wash it out good so the bricks are hydrated. Then I mix 1 part type 1/11 Portland ( lehigh brand is best ) 1/2 lyme and five sand. I’ve done buildings 10 years old and they look fine. Also, recently I was in england and learned there is a difference between hydraulic lyme which is what we have here and hydrated lyme wich works awsomr with old bricks just mixed 1/3 with sand. It does take longer to dry though.
I love this blog. Our home build in 1987 needs repointing and at some points, tuckpointing. That is what a busy mason diagnosed. Would it be safe for an oldish house built in 1987 to use Portland cement? What is the difference between repointing and tuckpointing? Also, the mortar in our home is colored. I am thinking that we can paint the whole brick walls with a similar flat color; is it acceptable? Why or why not.
(Also a huge problem we have is finding a repointing craftsman, as you advise. We request references of places they have repaired and nobody has provided any).
Thank you,
Mfay
Hi – If your mortar is colored the mason can reproduce that color – no need to paint it. I would think you can use Portland for a newer house. As for your other questions you are best contacting a mason. I really don’t know.
I am loving this site. We have a historic home in Western New York that was built in 1840 (!!!). The area where we have exposed the brick is in the kitchen. The wall is 20ft long by 10ft high. We are trying to determine how we’d like to proceed. We are thinking of washing the bricks first, but just based on the above information, would it be smart to remove the old mortar with a chisel and hammer, wash the wall, and then do repointing?
Hi – I wouldn’t repoint unless you really need to. Since it’s indoors it should be ok the way it is.
It is super sloppy because the wall was covered up with plaster. Since this is the main wall in the kitchen we’d love to make it look like a great feature wall.
Hello. Thanks so much for this article. For a house built in 1961 in central Virginia, what type of mortar do you think would work? Is there any other information you can offer on how I can determine what type of mortar is correct? After recent heavy rains, I noticed that the front steps we had relayed a year or so seemed to be an unusual color and looked very saturated. I’d like to ask the contractor what type of mortar he used and I’d appreciate any thoughts on what type of mortar should have been used. Thanks very much.
I’m not a mason but you should be ok with a house from 1961. Please refer to the Limeworks link.
Thanks so much. I will check out the Limeworks link. We had a mason come to our house today to give us a quote on repairs to the top of our chimney (not the guy who did our steps). He commented that one type of brick on our house – orange in color – is very, very soft. He went over to one of the bricks and scratched on it to show me how soft it is. His son who was with him said that those types of bricks just crumble when they are part of a building that is being demolished. When he said this, I remembered that I needed to ask about mortar. The mason said that he would use “S” mortar. I mentioned your article to him, and he seemed interested and said that he could possible add more sand to the mortar to make it softer. I told him I would send him your article so he could give me his thoughts. I’ll probably ask him to check out the Limeworks link also. Thanks again!
Talked to a guy at a local salvage company and explained to him what we have. According to him, our brick is old sand finished brick, and he thinks it was made from 1890 until 1950 (not sure how it wound up on a house built in 1961 unless it was made until the end of the 1950s). So, it seems like we may have brick that needs to have a softer mortar. I’m thinking of type O. Just as an aside, I mentioned my concern about mortar to the guy at the salvage company. He was very dismissive, saying that they wet the brick to keep it from absorbing moisture from the mortar. When I explained to him the issue raised in your article, he basically said, “you’re not going to live to be 200, so you won’t have to worry about it.” That’s not how I do things! But, I definitely appreciate the information he gave me about the bricks.
What a bad attitude. Hope he doesn’t get a lot of business.
Is it just as important to have the right mortar if it’s an interior wall?
I would guess so.
Yes. Only certain types of mortar should be used inside
Can painted brick exterior be repointed?
I believe it can be.
Following this article and comments, gratefully, my question is how? How can painted brick be properly repointed? How do you first remove the paint?
I’m the new steward of an 1870’s Italianate in Nashville, TN (Historic Edgefield). I’ve been unable to find a craftsman who understands the issues in repairing my brick mortar which was recently damaged by a severe hailstorm with 70mph winds. All my 1870’s brick was painted 36 years ago and to the eye, looked good, until the 1/2″ hail poked hundreds of holes in the mortar (not the brick). So now the mortar is exposed and sand just pours out…
I’m six months into trying to find knowledgeable help and mostly getting attitude like the one described above from a salvage yard. The last mason told me *just sandblast or pressure wash the house and repaint, because repointing the damaged areas would look too different from the undamaged areas.* I do have Simons (the super-soft orange) brick in the mix (I know from exposed walls in the interior). Anyone here or know resources in Nashville TN? I need a team to tackle this before the insurance recovery time window closes.
Wow – the worst thing you can do is sandblast the brick. The fired coating that protects it becomes a sponge and if you apply a sealer you have the same problem with moisture not getting out. If you can’t find a professional call your State Hist Pres Office for a referral of a Historic Preservation ARchitect and then ask them for a referral. HP architects are a world away from an ordinary architect just know.
We have 120 year old home the foundation is Fieldstone. There’s a significant amount of water coming in the basement. Additionally the mortar has turned to powder there so much sand in the Fieldstone it’s just falling off do you have any suggestions
As stated above – best to call limeworks.
Edison Coatings out of CT sells natural cement and mortar mixes that seem optimal for houses featuring brick and mortar crafted in the 19th century. http://www.edisoncoatings.com/store/historic-mortars.html
our house was built in the 1950’s with common redbrick; our chimney looks as though some of the mortar is gone from between a couple rows of bricks. How do we find out what type of mortar is safe to use on our 1950’s brick?
want to have it fixed but afraid to do more damage after reading this article
I think you are ok with 1950’s brick but I would contact Limeworks listed in the article.
I agree with everyone else on being grateful for information like this. Your other articles have been helpful too. We just bought a 1932 brick facade house in a Seattle and sadly chose the wrong people to start with repointing parts of it. I have two questions, the second is after my ramble.
The first is what makes brick no longer durable (my concern is contractors shaving off part of the brick when repointing). Or cracked off corners. I read that brick is softer on the inside and so exposure there could be as bad as missing mortar.
So we have cut the job loose as of yesterday and still need to figure out details since we had only paid the deposit. The issue is we just feel more and more that more damage was done than just aesthetic. We thought they would know at least how to match the rake and the color… they didn’t even try. And it’s Type S! They had dust all over after removing part of the old mortar and covered up the brick on some sides with the new gross grey saying the acid wash will take care of that. Anyway… now that it’s rained and we are looking at where we stand, it seems they grinded out parts of the brick too. We couldn’t see this before due to the dust and then the layers of grey mortar shoddily applied.
We really went wrong here, someone saying they have 10 years experience still doesn’t mean they repoint old or maybe even new brick properly.
I know you mention contacting lawyers above but we don’t have a lot of experience with this and would like your opinion or personal experiences on when it’s worth to get insurance or legal help involved. Part of me is Ok cutting our losses (and will get it repainted by another person who knows historical restoration and is well vetted) but when I’m seeing how more and more appears to be not just done wrong but possibly ruined…. so when asking for repointing… what damage is worth the pain of trying to get money back or something more? (Already have the pang of regret…!)
I know I should probably consult someone else but would appreciate any unofficial help you can give me. Also what kind of consultant should I be possibly looking for…?
Feel free to contact me directly. We’re young and still learning….
Hi Abigail – sorry to hear of your problem. It sounds like they really did a sloppy job. First you need to contact the experts. I am not an expert on this but Limeworks is. They are listed above. Contact them and explain what was done and they can better advise you if you have a case because you will need a professional statement saying what was wrong and why. They should be able to tell you if you have a chance in court too. Please keep us posted. Best of luck! Ken
The bricks in our foundation are starting to drop orange dust. Is this a mortar issue or simply the bricks are at the end of their life? Who should we be looking for to repair these? A mason educated on historic homes or is it better to start with a structural engineer first?
Good question about the dust. I really don’t know. I would contact a mason that knows straight Portland cement is bad.
Okay so after seeing some questions and misinformation I(as a mason woth over a decade experience and union training) straight Portland cement is NOT bad. It is an ingredient of any masons mix which as the article states come in MSNOK(easy way to remember; MaSoNwOrK) Type L is practically unused and unheard of. Now I believe the problem most people run into is not properly vetting their masons. I would always recommend staying away from nonunion contractors. If price is an issue and your just looking to throw a masonry structure together as fast and cheap as possible nonunion may be acceptable. They may lay good brick and block but thats typically the extent of their knowledge. If you need historical restoration, really any restoration, patchwork, or more elegant and durable structures go union all the way. When I was first initiated as an apprentice I was sent to the best trade school the union offers; IMI. At this school we start education at its most basic, the mixing and manipulation of all 5 types of mortar. That is the foundation of knowledge required to make repairs that dont stick out like a sore thumb. Essentially each type of mortar is made with the same ingredients. Portland, lime, and masonry sand. The difference lies in the ratio of these materials in proportion to each other. Most non union masons are really only familiar with S and N as this is typically all that is commercially available. In order to mix any of the other types the mason must buy all the ingredients separately and mix them in the proper ratios. We were also taught in trade school that the mortar is to be considered a sacrificial element in the wall. As long as your mortar is not stronger than your masonry units you should have no issues with spalling or eroding brick relating to a repair. So if someone hires me to do some restoration on an historical building I show up to the site with a number of things that I know must be inspected and considered before I even think about taking a grinder to joints. This list is as follows:
1. What type of masonry unit am I dealing with?
2. Is this veneer or facade or is it structural?
3. I examine the whole building and the state of its mortar joints; this informs me of a variety of things. IE are your joints raked or struck? What is the size of sand aggregate I can see in the mortar? How much mortar has eroded? Will I need to remove and replace any old, broken, cracked or otherwise defective units or Will i need to remove the face of any units and replace with soap(brick/block profile) also though many buildings can withstand a powerwash i wouldnt exceed like 1250 psi at the most because depending on the condition of your building you may totally blow out joints and compromise the integrity of the wall.
4. Find out approximate date built
5. Take a few chunks of mortar and crumble them to analyze the contents, this would reveal what type of sand i need to use as well as the ratio of portland to lime. (High portland content is grey almost blue when new and strong. Higher lime content is white to tan depending on the age and weathering.)
6. If the mortar appears to have changed color and is now tannish or buff colored I know I need to buy some color and mix in very small amounts until the mortar matches what is already in the building.(Keep in mind any mortar is goinf to lighten up considerably after curing so pointing on a building with tan or buff colored mortar will take a slightly brown mix.)
7. Finally I make as accurate of an estimate of time and materials as I can.
Anyways to make a long comment shorter, when doing restoration or any higher standard masonry work look for a reputable union contractor. We are taught trade secrets that have developed over thousands of years, we are all taught to meet a higher standard and we are taught the same things unlike a nonunion bricklayer who typically just learns a little more on each job they do, they just do not have the technical knowledge to make or even properly use the various types of mortar.
Thank you for this valuable information!
I loved your article … Thank you.
now I consider myself a pretty good handy man, and would like to help my son out on his house (built around 1890) from what I’ve researched and your article, I think I can give it a good shot to re-point the basement walls. My question is, type N mortar is rated about 750 psi for strength, and type O is rated at 350 psi, if I combine the two will I have a mortar around 550 psi for strength? example type N =1portland,1lime,6 sand …. type O = 1portland, 2lime, 9 sand …. I am considering using 2 portland, 3lime, 15 sand ! any opinion?
Honestly I have no idea. I seriously recommend you contact someone like Lime Works before you do anything. Good luck.
Hey idk if youre still curious but the prototypical mix ratio is 3 parts sand to every part cement lime. If you look at the mix you described: 2 portland+ 3 lime= 5 to 15 parts sand or 1:3. In other words yes this should be an acceptable mix. As far as the psi strength of this mix, I can tell you from experience that its very rare to end up making a 1:3 ratio mix thats too weak. Im not sure if its chemical additives or what but most of these mixes end up surpassing the strength they are rated for by a considerable degree. As the author of the article states I would be more concerned with making sure your mix doesnt end up too strong for the masonry units you are working with.
I have only a few small (1 inch) gaps where mortar is missing on random places on my house. Is there a kind of premixed mortar than can be pushed in that you would recommend?
I am not a mason – I have no idea.
Our house was built circa 1860. The brick was local, and has been painted over. Our biggest concern now is the foundation, which I believe is local limestone rock. The exterior needs to be re-pointed. Not sure what was used before but it is either eroded or crumbling. What would you recommend for re-pointing this limestone rock (we wish the rock to show not totally cover it over). Thanks!
I have no idea. Best to contact the expert I have listed above.
I just had my chimneys redone from the roof up, and crumbling bricks replaced on the shoulder, and the masons used type N. My house was built in 1978 with new or reclaimed chicago brick. Is type N too hard for chicago brick? I’ve been trying to find which type should be used with it, but i can’t find a straight answer. There are a lot of cracks around the rest of the house, and I want to be able to repoint them myself instead of paying through the roof for it, but want to make sure I’ll be using the right type.
N should be fine for 1978 brick. Did you contact Lime Works?
Type O is recommended for soft stone masonry. However O is not strong enough for load bearing and has performance issues if it is subjected to freezing temperatures often. What I would do if I were you is either use type N or you could use this middle ground recipe i have that has strength and properties that are halfway between N and O.
Type N: 1 part Portland 1 part hydrated lime to 6 parts of sand
Type O: 1 part portland 2 parts hydrated lime to 9 parts sand
My middle ground type: 2 parts Portland 3 parts hydrated lime to 15 parts sand
Note: most ratios end up being 1:3 Portland&lime: sand. Also the type of sand is very important
Hi great article . My home was built in 1935 in southern ca. Your thoughts on type of mortar would be much appreciated. You think n is ok or should still be o or k ? Thanks again
I would contact the company I listed for questions.
Hey Ken,
I came across your website by accident because I was researching repointing, and tuckpointing. It was very educational as well as surprising. I was not aware that it is more that just cement. We will be closing on a lannon stone house on December 14, 2020. Thanks for your help.
Luckily i was taught to use lime in older brick structures in my apprenticeship. I have been laying for 35 years and have restored many old brick structures that still look great today. But i do see “bricklayers” ( not masons)
using wrong mortar and destroying historical structures and its heartbreaking. I take pride in restoring historical landmarks. My work can be seen over many cities and even back down in woods on a long dirt road.
I love it
I’ve recently began working on my basement. Initially I was only going to replace the old terrocota drain/sewage lines that had failed under the concrete floor. While doing this I noticed the northwest corner of my home was taking in a good amount of water under the slab. I didn’t install a tile drain because my home was built around 1900 and the foundation is brick and does not sit on a slab. However I did remove some of the hollow sounding parging in the area where the house is flooded and noticed the interior brick work has significant sprawling, crumbling mortar and the bricks are staggered. I’m attributing this to settling due to the fact that the house is a new england home built on heavy clay and it’s the corner which I’ve been told is the lighter section of the house. Outside the house the soil is poorly graded and there are a couple small stair step cracks in the mortar. I’ve extended the downspouts appx 10′ from the foundation and added a sump pump (no tile drain) just to push standing water out of the house after a thaw or a heavy rain. I’ve applied silpro to the walls that weren’t parged and looked pretty good. Is there anything recommend for the area I removed the parging inside the basement? Should I tuck point the brick? Replace some brick? Clean it up and apply silpro? Also, should I wait until spring
The parging has been holding moisture in the wall allowing the brick to rapidly deteriorate. It’s nothing to do with settlement, that happens within the first 10 yrs of house being built. Remove it all and let your basement breath. Stop putting any kind of sealer on the walls, it’s doing the same thing as the parging, and will need constant repainting of it.
You 2nd point on making sure the new mortar is softer is such a key element and honestly hadn’t thought of it before. Makes total sense that moisture will follow the path of least resistance to escape – I’d much rather it flow through mortar than brick that is already old and weathered… awesome article and warning for all the DIY’ers and Masons out there. Thanks!
Thanks for sharing!
SO WHAT IS THE MEASURE FOR MIXING MORTAR FOR POINTING EXISTING BRICK AND MASONRY STONE STAIRS
It depends on a lot of factors. I would contact the resource I recommened.
(9 years after article was written) Great article Ken! Walking around town, I’ve often seen walls with the spalled bricks and wondered about the cause. Now we know why. Clueless repointing a decade or two ago!
NPS has a good preservation brief that goes over this as well.
https://www.nps.gov/tps/how-to-preserve/briefs/2-repoint-mortar-joints.htm
Old article I know, but sorry I have to speak up. O and K are too soft and not recommended for outdoor use! N is the softest you should use in and outdoor application.
That kind of mortar is only good for brick structures built from the 1950’s. Older brick can’t take the strength of modern mortars and will cause more problems than you have now.
Great article, so glad I found this before repointing the mortar of the brick on my grandparents home, and explains why the bricks around the base of my other grandparent home just broke and crumbled years after my grandfather had it repaired. I could tell looking at the mortar of the joints that it was different than modern homes. Certainly is softer, and doesn’t seem to crack or crumble like I’ve seen modern mortar do. It has just slowly been washed away by the water after 60 years.
What do you do to fix it? We’re buying a house and one of the repairs we asked for was repointing the brick. It was done a week ago. Can we remove the bad mortar and put the right kind in?
I would check with the pro I have listed but I would think it can be redone.
It’s difficult to re-point with NHL mortars if you don’t know what you’re doing. Better to employ a professional Historic Masonry repair company, who know what they’re doing. There are demolition processes, depths of joints to know and curing processes, that need to be done by someone with expert knowledge.
Whoever wrote this article without any knowledge of the use of NHL Hydraulic lime mortars, should either do better research to educate themselves, or not write such nonsense in the first place.
A simple reading of the Secretary of the Interior’s guidelines for the rehabilitation of Historic properties (2012 revision) will be all you need to know when it comes to re-pointing your old or Historic building.
As a rule of thumb, Anything built before 1920 in the USA will have a high lime content, as Portland cement manufacturing was only just beginning to take off in the USA at that point. You should also bear in mind that the early mortars of that period were significantly weaker than those made today. If you have a Victorian building it will consist of either a 100% lime based mortar or a Rosendale cement which was a natural cement found originally in Rosendale NY, and subsequently successfully in Pennsylvania and Virginia. They kept the name Rosendale as it was recognized by most people of the time.
You cannot, under any circumstances put a Portland mortar on top of a lime mortar, no matter how feeble you make the Portland. The Portland dries to a hard finish, which allows moisture and water to penetrate, but not escape from the wall. It then re-slakes the lime mortar beneath leading to a chemical reaction which will push the Portland mortar out of the wall over a short period of time, between 5-10 years. Also the trapped moisture can only migrate inwards because of the hard exterior of the Portland mortar.
Adding hydrated lime to a Portland mortar is done for plasticity and nothing else. It has no binding properties whatsoever.
When re-pointing most historic buildings, you should use an NHL Natural Hydraulic lime mortar, either a 2 or 3.5 level of hardness.. This closely emulates the mortars used in Victorian and pre-Victorian times.
Limeworks is the East Coast supplier of ST. Astier NHL, which comes from France and is made in exactly the same way it was hundreds of years ago. There are no commercial Lime kilns in the USA today, that make NHL cements. The last one closed in 2008 in Virginia. They are the most helpful people there is when it comes to Historic building techniques.
We are Historic Masonry repair specialists, and we’ve been removing the wrong mortar from American buildings since 2000 when we first came over to the USA. 90% of our work, is undoing the work American masons did from the 70’s until now, and they’re still doing it, through a complete lack of knowledge.
If you have an old building you want restoring or rehabilitating correctly, you can find us on line at Windsor Masonry.com We work for many Government agencies, including the National Park service, the defense dept., the GSA, the Coast Guard, Universities, Churches, schools and private individuals.
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I thought we were saying more or less the same thing but would really appreciate any advise in making corrections.
Thanks for the info!
Hello
I have a home built around 1920. It has stone basement walls built to slightly less than ground level, with what looks like two rows of brick about 30″ high than the wood structure sitting upon this.
in some sections of the rock basement walls, the mortar has turned to what I would call sand and is easily scratched from the joints.
In some sections of the brick wall, the mortar has also turned to sand and I can pull bricks right out of the top row as well as random bricks having turned to red powder on the surface to an undetermined depth.
My main question is, can the older disintegrated bricks be removed and replaced with modern equivalents? As far as the makeup of the mortar I guess I would have to have it analyzed although it looks as if it was patched in the past and I would guess it wasn’t the proper material.
I don’t know – seek a pro that knows what they are doing. Asking about Portland cement is a good test.
Do you know any masons in Brooklyn, New York who use rappelling scaffold?
don’t know what that is
Good morning,
Very good information.
Thank You
Bernard
You probably saved my house! After moving into our 1890 VT brick cottage, we were very worried that we would not find a mason. What little repair had been done on the house was done by local self described builders who clearly used cement when they did anything on the brick. Gratefully, after spending much of the winter seeking a real mason, I found a terrific guy who is spending every weekend working on the bricks. It will be a long summer for him and for us, but everything he is doing makes a wonderful difference. So far, the interior brick structure (brick on brick) seems to be solid, so he hasn’t had to repair that, but there is much more to do and we shall see. Meanwhile we love watching him work and the results are heartening.
I’m having my re tuck pointed right now in 2024 and the the home was built in 1928. I stumbled across this page and asked my mason what he is using. He said he will use type S. Is this going to be ok?
I have been having a lot of anxiety around this project because we had soft mortar on the bottom at the water table and mortar that came out but he did say it was hard still at the top. I went with doing the whole house to have it match since no pointing has ever been done on it…. I really hope I have not made a terrible decision and before the mortar goes in I want to tell him to stop and get a different kind if needed!
Hi – the info you need should be in the article. I there is something you cannot find, call the company I list for a better explanation.