Masonry wall systems are construction systems that use masonry materials such as bricks, stone, or concrete blocks to build walls. Usually, these materials are stacked on top of each other and held together with mortar. Masonry is the oldest technique used to build buildings or structures. Concrete masonry is a popular building material due to its strength, durability, economy, and resistance to fire, noise and insects.
However, to work as designed, concrete masonry buildings must be properly constructed. This TEK provides a brief description of the variety of materials and construction methods currently applicable to concrete masonry. In addition, a typical construction sequence is described in detail. While mortar makes up approximately 7% of the typical area of a masonry wall, its influence on the performance of a wall is significant. The mortar binds the individual masonry units together, allowing them to act as a composite structural assembly.
In addition, the mortar seals joints against moisture and air leaks and adheres to joint reinforcement, anchors and flanges to help ensure that all elements work as a single unit. Most concrete masonry constructions are mortar constructions, meaning varying the bonding or joining pattern of a concrete masonry wall can create a wide variety of interesting and attractive appearances. In addition, the strength of the masonry can be influenced by the bonding pattern. The most traditional joint pattern for concrete masonry is the vertical joint, in which the vertical joints of the head are offset by half the length of the unit. Excluding the construction of linear joints, the most popular joint pattern in concrete masonry units is pile bonding.
Although stacked bonding usually refers to masonry constructed so that the joints of the head are aligned vertically, it is defined as masonry placed so that the head joints, in successive rows, are horizontally offset by less than a quarter of the length of the unit. (ref. TEK 14-6, Bonding patterns for concrete masonry (ref. The alternative to construction with mortar is dry-stacked construction (also called surface agglomerate), in which the units are placed without mortar and then both wall surfaces are covered with surface adhesive material.
Wedges or floor units are used to maintain elevations. This construction method allows for faster construction and is less dependent on worker skill than construction with mortar. In addition, the adhesive surface coating provides excellent resistance to rain penetration. TEK 3-5A, Surface agglomerated concrete masonry construction (ref.
To achieve a uniform mortar from one batch to another, the same quantities of materials must be added to the mixer and in the same order. Mortar mixing times, placement methods, and tools must also be consistent to achieve a uniform mortar for the entire job. The mortar should stick to the pallet when picked up and slide easily off the pallet as it is spread. The mortar must also contain enough water so that the board mortar does not lose its ability to work too quickly and so that the bricklayer can extend the joints of the mortar bed before the construction of the masonry.
The mortar must also be stiff enough to initially support the weight of the concrete masonry units. The joints of the head and bed usually measure 1 cm. The mortar must extend completely along the lining surfaces of the hollow units to the thickness of the front cover, so that the joints are completely filled. Solid units must be completely coated with mortar. While it is important to provide sufficient mortar to properly position concrete masonry units, excessive mortar should not extend into drainage cavities or into the cores where the grout is to be placed.
For masonry with grout, the protrusions of the mortar extend more than ½ inch. Experienced masons claim that they can place approximately five times more masonry units when working on a masonry line than when using only its straight edge. The mason line provides the bricklayer with a guide to position the block in a straight, plumbed position, at the correct height and level. The line is attached so as to serve as a guide to align the top of the field.
If a long path is to be drawn, a trigonometer can be placed at one or more points along the line to prevent the line from sinking. Before starting work, the bricklayer must check that the line is level, tight and that it does not slip out. Every mason working on the same line must be careful not to position a unit so that it touches the line. This will slightly deflect the line and cause the rest of the route to be misaligned.
The line should be checked from time to time to ensure that it has remained in position. Before building the block wall, the base must be level and clean so that the mortar adheres properly. It should also be reasonably level. The base must be free of ice, dirt, oil, mud and other substances that may reduce adhesion. The first step in placing the wall is to take measurements starting from the foundations or floor plans and transferring them to the foundation, foot or slab of the floor.
Once two measurement points have been established, corner by corner, a chalk line is marked on the surface of the base to establish the line where the face of the block will be placed. Because a line of chalk can be washed away by rain, the surface can be marked with an oiled crayon, line paint, nail or screwdriver to mark key points along the chalk line and redraw a line with chalk along these key points. After marking the entire surface to determine the location of the walls, openings and control joints, a final check must be made of all measurements. Starting at the corners, the bricklayer places the first row without using mortar to visually check the dimensions of the floor plane or foundation and check if the first row actually fits the plane. During this dry design, concrete blocks will be placed along the length and width of the foundation, the floor slab, and even along the openings.
This will show the bricklayer how the joint will hold above the opening. It's useful to note that there are no more than 5 inches. In this drill, the bricklayer can check what the block will look like for the openings above the windows on the first floor, etc. These checks will show if it is necessary to cut units or not. Window and door openings must be verified with storefront plans before construction.
Once this is done, the bricklayer marks the exact location and angle of the corners. It is essential that the corner be built as shown on the base or floor plan, to maintain the modular dimensions. Building the corners is the most precise job for the bricklayer, since the corners will guide the construction of the rest of the wall. A pole in the corners can make this job easier. An angular mast is any type of pole that can be propped up in a true vertical position and that keeps a mason's line tense without bending.
The corner posts of cinder block walls should be marked every 4 or 8 inches. Once the corner posts are properly aligned, the first row of masonry is placed in mortar. Typically, a mortar joint between ¼ and ¾ inches. The initial joint of the bed should be a complete joint on the base, foot or slab.
In some areas, it is common practice to place the first layer of masonry directly on the still-wet concrete base with water. When the reinforcing bars protrude from the base or slab, the first row is not placed on a full bed of mortar. In this case, the bricklayer leaves a space around the reinforcement bars so that the block is seated in the mortar, but the mortar will not cover the area adjacent to the blocks. This allows the grout to adhere directly to the foundation in these places.
After spreading the mortar on the marked base, the first corner block is carefully placed. It is essential that this first course be flat and flat. Once the corner block is in place, the main blocks are placed in three or four blocks that come out from each side of the corner. The head joints are greased with butter beforehand and each block is pushed lightly against the block instead.
This push will help make the head joint tighter, but it should not be so strong as to move the block which is already in place. Care must be taken to spread the mortar over the entire height of the head joint so that there are no voids or voids. If the bricklayer is not working with an angular mast, check that the cables in the first row are level, leaded and aligned with a level. Usually, the corners and cables are built at the height of the scaffolding, with each row retreating half a block from the lower row.
The second plate will be placed on a complete mortar bed or with a front cover, depending on be specified. Each row between the corners can now be easily placed by stretching a line between them. It should be noted that a block has thicker networks and front layers at the top than at the bottom. The thickest part of the nets should be placed face up.
This allows you to hold the mason with your hand and increase the surface area to spread the mortar. Subsequently, the first row of blocks is placed from corner to corner, leaving gaps, with a locking block to complete the row. It is important to extend the mortar for the locking block so that all edges of the opening between the blocks and all edges of the locking block are greased with butter before carefully placing the locking block in place. In addition, the location of the locking block must be varied from field to field so as not to create a weak spot on the wall. The units are leveled and the pipes are placed while the mortar is still soft and flexible, to avoid losing the attachment of the mortar in case the units need to be adjusted.
As each block is placed, the mortar that is squeezed out with the edge of the pallet must be cut and care must be taken that the mortar does not fall from the pallet onto the wall or stain the block when removed. In case mortar gets on the wall, it is best to let it dry before removing it. All of the mortar removed from the joints of the mortar can be thrown onto the mortar board or used to butter the joints of the block head instead. Mortar that has fallen to the ground or scaffold should never be reused.
When the mortar is hard with the fingerprints of the fingers, the joints of the head are machined, then the horizontal joints are finished with a sled guide and any burrs that develop are removed with the blade of the paddle. When finishing the joints, it is important to press firmly, without puncturing the joints. This compresses the joint surface, increases water resistance and also promotes bonding between the mortar and the block. Unless otherwise required, joints must be machined with a rounded joint to form a concave joint.
Once the joints are worked out, the wall is ready to be cleaned. Masonry surfaces must be cleaned of imperfections that may detract from the final appearance of the masonry structure, including stains, efflorescence, mortar droppings, grout droppings, and general dirt. Cleaning is most effective when carried out during wall construction. Procedures such as cleverly cutting off excess mortar and brushing the wall before lifting the scaffold help reduce the amount of cleaning.
necessary. When the mortar falls on the surface of the block, it can often be removed more effectively by letting it dry and then detaching it from the surface. If there are any stains on the face of the block, you can rub it with a broken piece of block or brushed with a hard brush. Sometimes, masons don't spend more time keeping the masonry surface clean during construction, as more aggressive cleaning methods may have been specified once the wall has been completed.
This is usually the case with masonry construction with grout, where grout stains can be common and can be general cleaning is necessary. The cleaning method must be chosen carefully, as aggressive cleaning methods can alter the appearance of the masonry. The cleaning method can be tested on the sample panel or in an inconspicuous place to verify that it is acceptable. It states that all unfinished masonry works must be covered on top to protect them from the elements.
Although it is desirable to maintain strict construction tolerances depending on the appearance and, potentially, the structural integrity of a building, it must be recognized that factors such as the conditions of the previous construction and the lack of modularity of the project may require the bricklayer to slightly modify the masonry construction with respect to the plans or expected specifications. An example of this is when a bricklayer must vary the thickness of the joints of the headboard or bed to fit inside a frame or other pre-existing construction. The ease and flexibility with which masonry construction adapts to such changes is an advantage of using masonry. However, the masonry must still be built within certain tolerances to ensure that the strength and appearance of the masonry are not compromised.
Collar joints, grout spaces, and cavity widths are allowed to vary by —¼ of an inch. The provisions for the width of the cavity are for the space between the elbows of non-composite masonry. The provisions do not apply to situations where the masonry extends beyond floor slabs or sheet beams. Figure 2 shows the tolerances that apply to walls, pillars and other masonry construction elements.
It is important to note that the specified dimensions of concrete masonry units are 13 cm. Therefore, an 8-inch wall specified to be built. Instead, the tolerance should apply to 7 inches. The alignment of pillars and walls that extend from floor to floor can vary by ± ¾ inches.
The top surface of load-bearing walls must remain level within a slope of ± ¼ inch. NCMA TEK Note 03-08A, revised in 2001 The NCMA and the companies that disseminate this technical information disclaim all responsibility for the accuracy and application of the information contained in this publication. Masonry is a term used to indicate the part of the construction that uses bricks, concrete blocks, structural tiles made of clay and stone. These materials are held together with mortar. Masonry mortar is not a mixture of cement, the material used for sidewalks, patios or vehicle entrances.
The mortar mixture contains lime, sand and gypsum, each in the right proportions. The cement mix, on the other hand, has stones in the sand and does not contain lime. Bricks must be placed on English wood unless otherwise specified and must be well bonded. Each field must be truly horizontal, and the walls must be truly plumbed.
The vertical joints in the consecutive course must not be directly one above the other; the vertical joints in the alternate course must be directly one above the other.
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