Pro Tip

The Difference Between Mortar and Cement

Mortar is a mixture of sand and cements that is most often used to build brick or block walls. While that may sound like the same recipe used to make concrete, there are some intentional differences between the formulations for mortar and cement, which is why the materials should not be used interchangeably.

What is the difference between mortar and cement?

If portland cement concrete is one of the most widely used building products in the world, masonry mortar is close behind. Like concrete, mortar is also designed to be durable, but achieves its goal through finesse. Its strengths are quite low compared to concrete and it is never used in thick applications. It is much creamier and more workable than concrete.

If you play tennis, think of concrete as your most powerful serve when you are trying to smash the ball into or through your opponent so that they can’t return the serve. Then think of mortar as a very gently placed lob close to the net that gets your opponent leaning the wrong way with no chance of returning the ball. Both achieve the desired result of earning you a point. The point of this long-winded analogy is to let you know that using concrete and mortar interchangeably will lead to disaster.

How To Mix Mortar

Mortar can be made in one of two ways. The older method is to take portland cement, add hydrated lime and mix with fine sand. The newer method is to use masonry cement and fine sand. Masonry cement is simply a material made by most cement companies where they intergrind the portland with lime or other ingredients designed to produce high air content in a kiln. The results are the same. If you go to the store and buy a bag of mortar you will not be able to tell which method was used to make the masonry cement. There are some parts of the country where masonry cement is simply not available and you will only get portland/lime mortar. The good thing is that it doesn’t matter. Some masons will absolutely swear that you must use portland/lime while others insist masonry cement is the way to go. Just chalk it up to personal preference.

 

 

There are three things that make mortar very different from concrete

  1. Mortar has lower strengths than concrete
  2. Mortar must have the ability to retain water
  3. Mortar has a high air content compared to concrete

There are three widely produced types of mortar: Types M, S and N. Type M will achieve a compressive strength of 2500 psi at 28 days. Type S will yield 1800 while Type N yields 750. By way of reference most general concrete is in the 4000 psi range but can go as high as 8000 psi for special applications. The easy way to remember the strengths is by spelling out the word MASON WORKS.

Types O and K are not made commercially and can only be used for non-structural applications such as fixing old mortar that has fallen out.

Why isn’t mortar as strong as concrete?

Why not make mortar as strong as concrete? Shouldn’t all materials be as strong as possible? When you build a wall, you want the block or brick to be the strongest part of the wall. When the wall shifts, and almost all do over time, the weakest part is going to break. If the brick or block were to break, then the fix would be building a new wall. If the mortar crumbles, provided you don’t let it go on for years, you simply need to repoint the wall (replace mortar in areas where the old mortar fell out). This is a simpler and more inexpensive fix. One important reason why masonry cement or a portland/lime blend works well in a mortar joint and straight portland does not is the high air content. When temperatures dip below freezing, the water content in mortar freezes. As we know, frozen water takes up more space than liquid water. This means that it will expand and crack whatever is next to it. By intentionally putting lots of tiny air bubbles in the mortar, the expanded ice has somewhere to go without causing damage. Concrete generally has enough mass that this isn’t a problem.

Mortar must also be able to retain water for a certain period of time. Most masons mix up enough mortar to be able to lay a good amount of brick or block without having to stop and mix more. If the mortar they mixed doesn’t retain its flowable nature for at least an hour, the mason will simply add more water to bring it back to life. While this is a really bad idea, it is done in the field all of the time. The problem with this is that the strength of the mortar is designed around certain water to cement ratio. If the ratio is skewed, then so are you when the walls fail due to weak mortar.

Which Type of Mortar Should I Use?

So which mortar should I use? Commercial jobs will usually state which you are required to use. For non-specification work, Type S is usually a safe bet and is what most of you would use on your projects. For those who have a quest to know more, the best general rule is that if the wall is non load-bearing, such as a divider wall inside of a building, then Type N is sufficient. If the wall is below grade or carrying the load of the roof or several stories of brick or block use Type S. Type M is rarely called for and only used in certain large commercial projects.

Comments (50)

Jim Steigmeyer says:

My sidewalk edges are deteriorating due to using ice melt in the winter what product do you recommend to repair these edges?

Sakrete says:

Jim, a product like Fast Setting Cement Patcher would work great, assuming the damage is under 2″ in depth.

Check out this Pro Tips guide for more info on how to tackle that project.

Gregory Perkins says:

Is there any benefit to use type N mortar compared to type S? Such as cracking, water resistance, adhesion etc? If S shrinks less and has greater compressive strength, why would anyone want to use type N for any application ?

Sakrete says:

Gregory, this is really a question of matching the strength of the mortar to the strength of the block. The rule of thumb is that your mortar should be “softer” (aka weaker) than the block. You want any cracks to propagate through the mortar joint and NOT the block. Mortar can be repaired, block can not!

Type N is typically used for clay brick because of it’s lower (~750 psi) compressive strength. Type S (~1,250 psi) is often stronger than brick, which can actually cause the brick to crack!

Michael B. Hess says:

Thank you! Excellent article – very helpful.

John Kirstein says:

I am looking for a MORTAR mix to repair i.e. fill in spaces or holes left in the mortar lines where the old has been cracked and fallen out, or has been cracked and needs to be replaced.
The house is 68 years old and I remember the large tray laying on the pre-driveway area where the bricklayer made the mortar.
I have noticed in many repairs to other brickwork and mortar fixes, that the use of what appears to be a cement mix has been used; the colour being light gray versus our browner and coarser sandy colour , and, the size of sand being very fine versus our more coarse. our face brick does not support anything else except its 8-9 foot height, on 8 inch concrete block foundation.
My question is; What mix is going to be the best colour and texture match to our mortar lines which will best make for a quality match? Thank you so very much for this consideration.

Sakrete says:

John, the color of your mortar is going to be heavily influenced by the color of your SAND. That’s the dominant ingredient in mortar, so it sounds like your mission is going to be finding a good mason sand that matches the color you’re looking for and then mixing your own!

Michael says:

I’m pouring a slab for my generator and have some extra mortar. Can I combine mortar mix and concrete mix together? – 12 bags concrete with eight bags mortar

Sakrete says:

Michael, we wouldn’t recommend doing that. Might work, but no way to guarantee results…and you’re going to want that generator slab to hold up!

George Casey says:

How can concrete be protected from salts, acids and other harmful agents?
Like wood is protected by using paint, or metal is protected by using wax on an automobile.

Sakrete says:

George, any basic concrete sealer is all you need! Sakrete sells a couple: Cure ‘N Seal and Paver Sealer – both will work great!

Peggy says:

Very informative, thank you for the knowledge that I didn’t have prior to reading this.

ryan says:

Hi, I am looking for a product to make bricks with. because i have a lot of river rock i was planning on using them for displacement in the bricks.

Sakrete says:

Ryan, if you’re talking about CONCRETE brick, you could use pretty much any full-depth mix (assuming they’ll be more than 2″ thick).

Fred A Cappaert says:

i am setting a 4′ x 3′ shower base . Probably an inch of sakrete mortar mix type S. I have an 80 pound bag. Can you tell me what 80 pounds will cover?

Sakrete says:

Fred, we’d actually recommend a product like Floor Mud or Sand Mix for shower bases. You’d need about 5x 50# bags for the project you’re describing.

Give us a call at 866-SAKRETE and let’s dig into this one together!

JohnPhillips says:

I have 30” high brick “sea wall” on a concrete footing at Lake Hamilton in Arkansas.
The lake level is drawn down annually from Nov thru Feb which fully exposes the wall for inspection. I am missing a few brick low on the wall and see many areas where the mortar has fallen out and small grass roots have come thru.
I power washed the wall and removed the roots and now would like to know which mortar I should use for these repairs.
Thank you,
John

Sakrete says:

John, assuming this is clay brick, we’d recommend Type N mortar. If it’s concrete brick, go with Type S!

Frank Azzoprdi says:

I am working on a special project and I don,t expect youth know the answer. but if anyone’s 2 cents is worth its weight in gold it is yours. I am going to enclose a stainless steel time capsule in either cement or mortar and bury it at sea (dump it in the ocean). I would like for the cement mortar to break up in 200 years or better. so that when the cement breaks down the capsule will wash ashore. I want the cement or mortar to hold up at least 200 years……if it holds up longer even better. what is the best product to use. If you cant answer I understand. this is not your everyday construction project. I thank you for any comments you may have for this project. thanks frank azzopardi

Sakrete says:

Frank, that is a VERY interesting question, but unfortunately way above the level of concrete chemistry we get into around here.

Way too many variables to consider to give you a straightforward answer…but gut says that you’d want something very dense and high-strength like a Precision Non-Shrink Grout. Not sure she’ll make it 200 years in salt water, but it’d definitely give it a run for it’s money!

Frank Raddenbach says:

Thanks for the update was very helpful.

Frank Raddenbach says:

Thanks for the update was very helpful.good to know before using.

j says:

Type O and K are absolutely structural. Historic buildings used these lower strengths because it is more permeable, and mortar is really only glue designed to hold bricks together. Bricks make the strength of a wall, while mortar glues them together and allows the wall to breathe and dry out.

Elizabeth says:

Im going to repoint a very large and tall sandstone retaining wall on my property. I live in south central Pennsylvania, where winters can be very cold. I’ve seen so many conflicting opinions about what mortar to use, ranging from Lime mortar to portland and sand, and anything in between. Could you help to clear up some of the confusion around suitable material for the repair to my wall? The mortar is currently very cracked, with many loose stones. It was built around 1955, and has received little attention since then.

Sakrete says:

Elizabeth, hope we can clear this up a bit. The most important consideration isn’t the mortar “formula” (eg. Portland, lime and sand vs. masonry cement and sand), but the strength. Because sandstone is a very soft material (as far as stone goes), you want to use a similarly “soft” mortar.

We’d recommend looking for a specialty mortar called “Type O”, which is sometimes also called “tuckpointing mortar”. You’re not typically going to find this at a big box retailer – you may need to call your local masonry supply yard.

Give us a call at 866-SAKRETE if you’d like to talk through this one more!

Gregory Zancanella says:

A gap has developed over the years between bricks that are a boundary on a patio,,,what should I use, the gap is 1/4 inch

Sakrete says:

Gregory, that depends on the material that was originally holding the bricks together. The easy solution is a flexible polyurethane sealant, but you might also consider “tuck pointing” with a Type N mortar.

If you have photos or more information, shoot us a note on social or call us at 866-SAKRETE!

Ravi Sahu says:

Excellent 👌

Steven Crain says:

This is so interesting. Thank you. Do you have any suggestions of books I can read to start learning more about this topic.

Keith Brewer says:

Hello, I live in Ottawa, Canada so the freeze/thaw cycle is important in choosing the correct cement. I have a 30 foot by 4 foot flagstone walkway, 2001. The 6″ reinforced concrete slab has held well. One inch thick stone/slate was laid into “NORMAL PORTLAND CEMENT MORTAR”, with joints between stones filled with “CEMENT MORTAR” – I do not know what the composition was of these two “CEMENTS” but they have broken down into sand, by the looks of it.
Request: Are you able to advise on the exact cement I should use to re-lay the stones and fill in the joints between the stones?
Many thanks

Sakrete says:

Not sure we’re going to be able to figure out what the old material is, but easy recommendation for a new product! Typically Sand Mix is the go-to for paver bedding, and it can also be used to grout the joints between the stones by mixing the product and applying with a grout bag.

John says:

I recently had my brick chimney rebuilt by a masonry contractor. At the top of the chimney, where the flues penetrate, he capped it with a 2-3″ thick layer of what I think is Type S masonry cement. I’m seeing some cracks start to develop. From the article above, I suspect this layer may have been too thick for this cement. What would you recommend, is there a good way to seal those cracks?

Sakrete says:

If you’re just talking about minor cracks, that’s just a curing issue and is likely superficial. If you’re looking at anything over a hairline, it would be smart to seal it with a polyurethane sealant or potentially parge coat it with something like Top ‘N Bond.

Robert says:

This is a really excellent article. There are so many myths floating around about mortar and none of them are based on any kind of science.

Sakrete says:

Appreciate that – we’re all about the hard facts here!

Lorna Mattison says:

I have an old house. I used sakrete with color added to match my clay bricks. I cannot remember what type I used (old moment for sure) I need to do more as the bricks need to be repointed. Can you tell me what type of sakrete you would recommend. Thank you very much. Just so you know, it was a lot of fun to do the work myself.

Dave Jackson says:

Assuming you’re talking about repointing bricks, we’d recommend going with a Type N mortar. That’ll be the easiest to work with and most compatible with brick.

A load of fun for sure, but hats off for tackling it yourself!

Sam H says:

My friend has a brick sidewalk in southern PA. Many of the joins need to be replaced. Since this brickwork is horizontal instead of vertical, should we use concrete or Portland cement? What is your recommendation? He just bought the house last year and we don’t know what was used originally.
Thanks

Sakrete says:

The aggregate in concrete is likely going to be way too large to fill those small gaps – would consider using a mortar (Sand Mix, or Type S) applied with a piping bag. Just make sure to remove ALL old joint material before you start.

Ron Moore says:

I am trying to stabilize an old sandstone foundation corner on a New England home from the outside of the house (inside is inaccessible). From digging below grade a bit, the large stones are sill in place but with the old mortar washed out fairly large gaps left. I saw that Type O mortar was recommended for this type of repair, but I wondering if “plasticizers” or super plasticizers can be safely added to it to allow it to be poured as concrete and fill the gaps, while still protecting the soft stone after curing?

And Thank You for this very useful service!

Sakrete says:

Ron, that’s an interesting one that I’m not sure we’re qualified to answer quickly. Your solution sounds reasonable, but we’d strongly recommend giving a local historical restoration pro a call for their recommendation.

Oscar Brown says:

I use a mortar, for my construction blocks. In my retainer wall.

Raymond says:

Is it ok to simply use quick dry cement for mortar applications?

Sakrete says:

Raymond,
Mortar is formulated for minimal shrinkage, so it would not be recommended to use cement in this application.

Jack Cassidy says:

I am having a concrete barrel tile roof replaced. The tile I have selected is the Villa 900 by Westlake. It is a snow white sealed tile. My question is what material should be used to finish the capping tiles and joints, and does it need to be sealed once it is used to complete the installation.

Sakrete says:

Jack, we recommend you reach out to the experts at the tile company to help out with this. Goodluck!

Glenn Campanoli says:

Nice and simple explanation. Thank you.

Gregory Perkins says:

I am building a home on the coast in Florida with concrete blocks and in some cases poured concrete foundation. I have noticed all around me that at about 18 to 20 years that the rebar and reinforcing materials as well as lentils and steel beams embeded in concrete begin to corrode and cause spalling….essentially causing a loss of structural integrity much like the big condominium that collapsed in North Miami a year or so ago. What can be added to the concrete and mortar to prevent the salt air and sometimes water from corroding the interior steel structure? This must be a factor on highway bridges as well as the commercial buildings. We need to make the concrete non permeable and water tight and air tight I think. How do we increase the design life to more than 20 or 25 years?

Joey says:

The focus on mortar’s workability for laying brick and block walls is helpful. For someone tackling a small brick project at home, are there any recommendations on pre-mixed mortar versus mixing your own dry mortar mix? Las Vegas Foundations

Sakrete says:

Joey, we definitely suggest using pre-blended mortar mix over making your own batch. A pre-blended mix is faster, cleaner, and produces a better yield. Hope that helps!

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