The Different Types Of Masonry Walls
The strongest part of any building or any structure for that matter would be the masonry walls. As they provide strength and durability to any structure, and at the same time they help in controlling the temperature indoors and out. In general, it keeps the indoors in and the outdoors out. When you hear the word masonry the first thing that should pop into your head is a construction that uses mortar as its binding material. It also uses single or rather individual stones, bricks, granites, marbles, tiles, concrete blocks, and more. Mortar uses sand in its mixture unlike Spackle and other substances. The materials for binding mixture is made lime, cement, soil, and there are a few other items it can be made out of as well. Of course, how strong and durable the masonry wall construction is will depend on the type of materials used, the workmanship, and the quality of the masonry wall construction. It also depends on the kind of individual units that is used for the masonry walls and what the function is going to be for.
Here Are The Different Types Of Masonry Walls:
1. Masonry Walls that are load bearing…
The construction of walls that are built to be load bearing are masonry walls that is built with stones, rocks, cement blocks, or concrete blocks. Load bearing walls carry the weight that is transferred from the roof top to the house or buildings foundation.
These type of walls can be found on both the interior and exterior of the building. The load bearing walls are more economical than those that have a framed structures.
How thick a load bearing wall is will depend on the amount of load that is expected from the roof, it has to be estimated how much the load bearing walls will have to bear.
For instance, for a single floor home a load bearing wall could have a thickness of 230 mm, however, if there were a second or third floor the thickness would need to be increased.
There are reinforced load bearing walls and there are also un-reinforced load bearing walls.
There are load bearing walls that are reinforced, however, you are going to find some walls that are not load bearing buy are also reinforced. Reinforcements are built into walls that are expected to have excessive compressed loads, as well as a lot of tension forces.
There is a slight disadvantage to having un-reinforced masonry walls, and that is that they are prone to cracking, and can fail when under duress compression. they will give easily during earthquakes as well.
2. Masonry Walls that are reinforced…
Un-reinforced masonry walls have very little ability to with stand the forces of nature with it comes to heavy rain falls and high speed winds. Even the earth’s pressure alone can cause cracking in an un-reinforced masonry wall. Cracking can also come from the settling of the foundation.
These issues can be illuminated by using reinforced masonry walls from the start. This can be done by using reinforcement that is placed at specific intervals within the masonry walls, at both horizontal and vertical positioning.
It depends upon the amount of load bearing to be expected, and the structural conditions as to the size, quantity, and amount of spacing to be used.
3. Masonry Walls that are hollow…
The prevention of moisture reaching the interior of a building can be achieved by the use of masonry walls that are hollow or has a cavity. These work by providing space between both, the outside and inside faces of the wall.
The hollow space between the walls restricts prevents the heat from going through the walls and that is why these walls will help in controlling the temperature inside of the building.
Should the walls get exposed to any moisture for a given amount of time so that it starts to penetrate into the outer face letting the water/moisture reach the hollow or the cavity space it will simply drain downward.
After the water from the moisture begins to drain downward it then goes through what is referred to as weep holes and takes the water to the exterior, keeping it from effecting the building. The hollow and cavity areas are either coated with a coating that is water repellent, or by a damp proofing that works to reduce the chance of any damage to the structure itself.
4. Masonry Walls that are Composite…
This type of wall uses two or more units, whereas as unit means using stones and hollow bricks or bricks and hollow bricks. When this type of masonry walls are used it gives a much nicer appearance and is also more economical.
When working with composite masonry walls you’ll be putting together two wythes of masonry units by bonding each of them together. One of the Wythes can be hollow bricks and the other Wythe can be either stone or brick. A Wythe is a section of masonry that is one unit in thickness in a vertical section that is continuous.
The masonry sections referred to as Wythes are inter-connected by the use of steel ties or they are reinforced with a horizontal joint.
5. Masonry Walls that are Post-Tensioned…
Masonry walls referred to as post-tension are walls that are constructed in a way that it strengthens the masonry wall to withstand the forces of nature that can put a lot of tension on them, such as earthquakes, and the forces that can come from winds, such as tornadoes.
Walls with post-tension are constructed at the foundation level having post-tension rods running vertically through the Wythes or through the core of the concrete masonry units.
Once Masonry walls of this type have been completed and also cured the rods are then tensioned, and anchored to the steel that has been constructed at the top of that wall.
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.
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