The Different Types of Masonry Mortar…
Mortar is spread in between the masonry, grouts, and fills up the cavities of the masonry units. If you’d like to know more of the details read our article “Mortar vs. Grout.” The material that can be seen between the bricks is mortar. It is what makes masonry units stay together. Mortar plays an important role in masonry construction, and it is just as important to use the correct mortar or grout.
Determining the correct mixture for the mortar or grout in order to make it the perfect strength is not so easily done, what we can do is explain it in a clear and concise matter and hope that you can understand.
First, let us keep in mind that the mortar or grout needs to have just the right strength as to not be over bearing (load bearing in this case), the mixture to hold the masonry sections together should not be significantly stronger that what the masonry units are, as this can make the load bearing have an excessive amount of stress.
When mortar’s mixture isn’t to perfection it can end up weighing more than the masonry units themselves and cause damage to the structure in the form of cracking and/or spakling. Mortar has been given a classification by the ASTM C 270 (Standard Specification for Mortar for Unit Masonry). Mortar has four different types, you can find them listed below.
Furthermore, the type K mortar is not included any longer in the ASTM C 270 standard. Mortar is meant to be spread in between masonry bricks, holding them together and since mortar is actual a type of plastic it has the ability to accommodate any movement within the wall without doing any damage to the structure.
Mortar (Type M)…
Mortar (Type M) has a minimum 2500 psi and is use only in areas that areas that are expected to endure a significant amount of load bearing, wind forces, earthquakes, and etc. This particular type of mortar is usually used with stone. Mortar made with anything that has less strength may fail the structure and its job positioning prematurely.
Any time there are extreme lateral loads and/or gravity in the picture (such as the prior construction of the structure had below grade applications, and used lateral loads or gravity to retain the walls. Which might still present). This in conjunction with the use of stone and/or some other masonry units have a high compression strength.
Mortar (Type S)…
This is a mortar that has a minimum of 1800 psi. It is medium strength, and referred to as (Type S). It is a mortar that can be used for exterior structures such as a patio, as it is used for exterior walls that are considered below grade because it is stronger than (type N). This makes it a good choice when working with moderately resisting soil pressures that are below grade.
Where mortar (Type S) is usually used: It will usually be used in application considered to be below grade that have normal to moderate load bearing. Also, in areas where masonry comes in contact with the ground, such as a shallow retaining wall.
Mortar (Type N) for general purposes…
Mortar (Type N) is considered to be the most common type of mortar. This type of mortar is used when there are no other special circumstances that require a specialty for the load bearing of a structure.
Type N is a semi-soft masonry or stone and it is going to flex better than a mortar that has high strength. The more softer and flexible the mortar the less worries of cracking in the masonry units.
Mortar (Type N) can be used for applications of general purposes in masonry wall construction that is above the area where normal load bearing occurs.
Mortar (Type O)…
Mortar (Type O) is a mortar that has a low strength (a minimum of 350 psi). This type can be used for interior applications that are non-load bearing. In areas that are structurally sound, but need repairing for some reason, it will be repaired with (Type O) mortar.
This type of mortar has been used with masonry units having a low compressive strength, such as brownstone and sandstone. With this Type of masonry units it allows for more flexibility and thus, helps in preventing the unit to get cracks.
Mortar (Type O) is used for the interior applications that are not expected to carry much load bearing that has very little, if any at all exterior use. The use of this Type of masonry units is re-pointing the integrity of a structure and/or wall that is still intact.
Mortar (Type K)…
The (Type K) Mortar cannot be found listed under the ASTM C 270 anymore, although it will still be use in projects that have a pre-historic preservation need. This type of mortar will not cause any damage to a fragile structure, nor to any fragile stones as it has the lowest compressive strength of any mortar.
Mortar (Type K) is used for preserving pre-historic structures, which requires the use of a low strength mortar to avoid any damage. Keep in mind of course that Type K does not provide for load bearing.
Specifying the Type of Mortar…
Mortar has two different ways in which to issue documents for construction. You have a choice to choose or specify a mortar that hardens or you have the choice to choose or specify the ingredients of the mortar.
Mortar must be correctly specified for the structural requirements it is intended for if it is to adhere correctly. When not sure of thee mortar types and/or mixture be on the safe side and consult with an actual structural engineer.
A mortar that is less common than the others and used for critical applications is one that is supposed to be created in a laboratory. this type is also tested in the laboratory as well. It is the performance specification mortar.
After the twenty-eight day cure period the least compression strength that can be allowed can be identified by the specifier by the percentage of water the mortar retains and the percentage of air the mortar retains, along with the aggregate ratio the mix has. It cannot be used in the field until it has been tested.
Proportion specifications are identified by the specifier as it is determined what the ingredients exact proportions are in the mix, which is done with either weights or by volume. This way will allow the mortar to be mixed when out on a job. It takes less time to create the mixture.
FAQs
What are the different types of masonry mortar? ›
The 4 main types of mortar most commonly used are; Type N, M, S, and O. These types of mortar are thoroughly described in ASTM C 270, but we will briefly outline the characteristics and best use of each type here. Type N mortar is the most common type, and is usually recommended on exterior, above-grade walls.
What are the commonly used types of masonry walls? ›- reinforced with concrete block. Concrete Block Veneer. reinforced with concrete block. ...
- with steel stud. Brick Veneer. with wood stud. ...
- with reinforced cast in place concrete. Concrete Block Veneer. with reinforced cast in place concrete. ...
- Reinforced Brick. Reinforced Concrete Block. Stone Veneer.
2020/04/29. There are three basic categories of masonry brick walls: veneer, solid, and cavity. Each of these wall styles has unique features and individual strengths.
What is the most common type of masonry? ›Brick Masonry: Brick is the most popular material for masonry. They are known to be durable, long lasting, and have a classic look that has lasted the test of time. Bricks can come in a wide variety of textures and colors.
What are the 2 main types of masonry units? ›Common masonry unit types include clay and concrete units, which may be solid or hollow, and glazed or unglazed. Other masonry unit types include cast stone and calcium silicate units.
What are the 5 types of mortar? ›- Cement Mortar.
- Lime Mortar.
- Surki Mortar.
- Gauged Mortar.
- Mud Mortar.
There are four main types of mortar mix: N, O, S, and M. Each type is mixed with a different ratio of cement, lime, and sand to produce specific performance characteristics such as flexibility, bonding properties, and compressive strength.
What is the difference between mortar and masonry? ›Mortar is the bonding agent that integrates unit masonry into a wall. Think of it as not only the glue that holds bricks, stones, or blocks together but also as the element that holds them apart. Mortar is the workhorse and sometimes the sacrificial element.
How many types of masonry are there? ›Stone masonry has two main classifications: Rubble Masonry. Ashlar Masonry.
What are the 5 common masonry materials and tools according to their types and uses? ›The common materials of masonry construction are bricks and building stone such as marble, granite, and limestone, cast stone, concrete blocks, glass blocks, and adobe. Masonry is generally a highly durable form of construction.
How many types of walls are there? ›
Depending upon the purpose they serve, walls can be classified into two – load-bearing walls and partition (non-load bearing) walls. However, based on the functionality they serve, there are other types of walls like retaining walls, shear walls, parapet wall,s etc.
What is a Type 4 wall? ›Type IV-HT (Heavy Timber) construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of solid wood, laminated heavy timber or structural composite lumber (SCL), without concealed spaces or with concealed spaces complying with Section ...
What is the most common type of concrete masonry unit? ›Solid concrete blocks are commonly used, which are heavy in weight and manufactured from dense aggregate. They are very strong and provides good stability to the structures. So for large work of masonry like for load bearing walls these solid blocks are preferable. They are available in large sizes compared to bricks.
What are the 4 masonry products and properties? ›Modern masonry products include portland cement plaster (stucco), cements for masonry, mortars, concrete block, and clay brick. These materials can be used on the interior or exterior of structures in a wide range of environments.