Masonry Walls

What is Masonry ?

Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves.

The common materials of masonry construction are brick, stone, marble, granite, limestone, cast stone, concrete block, glass block, stucco, and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can significantly affect the durability of the overall masonry construction.

Types of Masonry walls

Based on load bearing• Load bearing masonry walls.• Non-load bearing masonry walls.

Based on construction• Solid walls• Veneered walls• Reinforced walls• Cavity walls

Load bearing masonry walls

A load-bearing wall (or bearing wall) is a wall that bears a load resting upon it by conducting its weight to a foundation structure.

The materials most often used to construct load-bearing walls in large buildings are concrete, block, or brick.

Non-Load Bearing Wall

Walls that are only intended to support themselves and the weight of the cladding or sheathings attached.

Non load bearing walls provide no structural support and may be interior or exterior walls.

SOLID WALLS Masonry units laid close together with all joints filled solidly

with mortar.

Solid walls are structurally bonded by metal ties, masonry headers or by joint reinforcement.

Where solid masonry walls are used, insulation and mechanical equipment are often installed within a furred space on the interior side of the wall. Below grade, insulation is often placed on the exterior side of the wall.

Types of Insulation In Solid Walls

Internal Wall Insulation

Will slightly reduce the floor area of any rooms in which it is applied (the thickness of the insulation is around 100mm)

Is disruptive, but can be done room by room Requires skirting boards, door frames and external fittings to be

removed and reattached Can make it hard to fix heavy items to inside walls – although special

fixings are available is generally cheaper to install than external wall insulation

External Wall Insulation Can be applied without disruption to the household  Does not reduce the floor area of your home Renews the appearance of outer walls  Improves weatherproofing and sound resistance. Fills cracks and gaps in the brickwork, which will reduce draughts Increases the life of your walls by protecting the brickwork Is best installed at the same time as external refurbishment work to reduce the cost Is not recommended if the outer walls are structurally unsound and cannot be repaired.

Reinforced Masonry Walls

Reinforced masonry is any type of brick, concrete or other type of masonry that is strengthened or fortified with the use of other building materials to increase resistance to deterioration due to weight bearing or other forms of stress

One of the most common examples of reinforced masonry involves exterior walls that are created using concrete blocks or clay bricks. Along with the blocks or bricks, steel rods are worked into the structure, often using some type of vertical framework that aids in allowing the walls to bear up under its own weight, and the weight of the connecting walls and floors within the building.

The weaknesses of the masonry without reinforcement: 1. the sensitivity to cracks2. the low flexural bearing capacity

Reinforcing in brickwork is applied for two causes: masonry is a quasibrittle material and is very sensitive to cracking. Therefore, one part of the cracks can be prevented by using reinforcing bars or mesh embedded in the bed joint, or the size of cracks can be significantly decreased. . The flexural (tension) bearing capacity of masonry increases considerably with reinforcing.

Using reinforcement to prevent cracks horizontal bed joint reinforcement can be applied in the following cases :

1. if temperature changes or moisture content variations occur, the bricks may dry out, and cracks will arise as a consequence of shrinkage.

2. Strains resulting from differential settlement or

3. creep can cause big cracks.

4. At the corner of a building and at the cross junction cracks are very common due to the different strain of the differently loaded wall sections. This type of cracks can be decreased with the reinforcing of the junction. In the the consecutive layers of a T junction can be seen.

5. Infill walls in reinforced concrete frames can suffer damage due to the deflection of the floor.

6. In the place of concentrated load induction), tensile stresses occur in the plane perpendicular to loading, which can be handled by the bed joint reinforcement. Increasing the load bearing capacity, the reinforcement improves the stiffness of the masonry, and it distributes the stresses almost uniformly. For example by increasing the capacity of the masonry lintels or beams around openings, frameworks and steelworks may be prevented. For that purposes, prefabricated reinforcement meshes and lintel hooks are available.

7. If the walls of cellars and retaining walls are unable to carry the loads from the pressure of the soil, it is recommended to use vertical joint reinforcement; however, the implementation is more difficult.

The Types of Reinforced Masonry WallsDepending on which materials are used, and how they are located, reinforced masonry (RM) walls can be divided into the following classes: •confined masonry•reinforced cavity masonry•reinforced solid masonry•reinforced hollow unit masonry•reinforced grouted masonry•reinforced pocket type walls.

VENEERED WALLS

Veneered Masonry Wall

A brick veneer wall is constructed by having a non-structural external layer, usually with bricks and it isbacked by an air cavity.

The innermost element of this type of wall is structural can consist of wood, metal framing or masonry.

A brick veneer construction has many advantages over solid masonry. It shares some of the advantagesof a cavity wall.

A brick veneer masonry wall is light weight, thermally efficient and can help in reducing costs.

Advantages

The airspace between the brick veneer wall and the structural element acts as a drainage system.

The cavity can be insulated and this improves the thermal performance of the wall.

The structural element can be constructed first and this allows the rest of the construction to proceed. The brick veneer can be completed simultaneously.

A brick veneer construction takes less time to complete than a solid masonry wall which will give cost savings.

A veneer wall will weigh much less than a solid wall. Since the weight is less, the cost of the foundationand structural support can be reduced.

Disadvantage Masonry walls are durable and long lasting, but they have one weak point: water penetration.

Solution Flashing

Some examples of brick veneered masonry walls.

CAVITY WALLS

INTRODUCTION

THE CAVITY WALL METHOD OF CONSTRUCTION WAS INTRODUCED IN THE NORTHWEST EUROPE DURING THE 19th CENTURY AND GAINED THE WIDESPREAD USE FROM 1920’S.

IN SOME EARLY EXAMPLES STONES WERE USED TO TIE THE TWO LEAVES OF THE CAVITY WALLS TOGETHER.INITIALLY CAVITY WIDTHS WERE EXTREMELY NARROW AND WERE PRIMARILY IMPLEMENTED TO PREVENT THE PASSAGE OF MOISTURE INTO THE INTERIOR OF THE BUILDING.

THE CAVITY WALLS CONSIST OF TWO SKINS SEPERATED BY A HOLLOW SPACE (CAVITY).

THE SKINS ARE COMMONLY MASONRY SUCH AS BRICK OR CONCRETE BLOCK. MASONRY IS AN ABSORBENT MATERIAL AND THEREFORE WILL SLOWLY DRAW RAINWATER OR EVEN HUMIDITY INTO THE WALL.

THE CAVITY SERVES AS A WAY TO DRAIN THIS WATER BACK OUT THROUGH WEEP HOLES AT THE BASE OF THE WALL SYSTEM OR ABOVE WINDOWS.

THE REASON CAVITY INSULATION KEEPS HEAT IN IS THAT THE POLYMER AND AIR IN THE CAVITY ARE GOOD INSULATORS.

Construction work performed during the erection of stonework on buildings and structures made of natural and artificial masonry materials.

Masonry work is a complex of processes that  includes, in addition to the basic processes (the  laying of brick or other stone in mortar  the delivery and  laying out of the stone, and the  smoothing of the mortar), related auxiliary processes (the  erectionof  scaffolding and  trestles and preparation of the materials at the  construction site).

Masonry  is commonly used for the walls of buildings, retaining walls and buildings. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either weight-bearing or a veneer. Concrete blocks, especially those with hollow cores, offer various possibilities in masonry construction. They generally provide great compressive strength, and are best suited to structures with light transverse loading when the cores remain unfilled. Filling some or all of the cores with concrete or concrete with steel reinforcement (typically rebar) offers much greater tensile and lateral strength to structures.

ADVANTAGESThe use of material such as bricks and stones can increase the thermal mass of a building and can protect the building from fire.Most types of masonry typically will not require painting and so can provide a structure with reduced life-cycle costs.Masonry is non-combustible product.Masonry walls are more resistant to projectiles, such as debris from hurricanes or tornadoes.Masonry structures built in compression preferably with lime mortar can have a useful life of more than 500 years as compared to 30 to 100 for structures of steel or reinforced concrete.Bricks are fire resisting material

DISADVANTAGESExtreme weather, under certain circumstances, can cause degradation of masonry due to expansion and contractions forces associated with freeze-thaw cycles.Masonry tends to be heavy and must be built upon a strong foundation, such as reinforced concrete, to avoid settling and cracking.Other than concrete, masonry construction does not lend itself well to mechanization, and requires more skilled labor than stick-framing.Masonry consists of loose components and has a low tolerance to oscillation as compared to other materials such as reinforced concrete, plastics, wood, or metals.

STRUCTURAL LIMITATIONSMasonry has high compressive strength under vertical loads but has low tensile strength (against twisting or stretching) unless reinforced. The tensile strength of masonry walls can be increased by thickening the wall, or by building masonry piers (vertical columns or ribs) at intervals. Where practical, steel reinforcements such as wind posts can be added.

VENEER MASONRYA masonry veneer wall consists of masonry units, usually clay-based bricks, installed on one or both sides of a structurally independent wall usually constructed of wood or masonry. In this context the brick masonry is primarily decorative, not structural. The brick veneer is generally connected to the structural wall by brick ties (metal strips that are attached to the structural wall, as well as the mortar joints of the brick veneer). There is typically an air gap between the brick veneer and the structural wall. As clay-based brick is usually not completely waterproof, the structural wall will often have a water-resistant surface (usually tar paper) and weep holes can be left at the base of the brick veneer to drain moisture that accumulates inside the air gap. Concrete blocks, real and cultured stones, and veneer adobe are sometimes used in a very similar veneer fashion.

Most insulated buildings that utilize concrete block, brick, adobe, stone, veneers or some combination thereof feature interior insulation in the form of fiberglass bats between wooden wall studs or in the form of rigid insulation boards covered with plaster or drywall. In most climates this insulation is much more effective on the exterior of the wall, allowing the building interior to take advantage of the aforementioned thermal mass of the masonry. This technique does, however, require some sort of weather-resistant exterior surface over the insulation and, consequently, is generally more expensive.

DRY SET MASONRYThe strength of a masonry wall is not entirely dependent on the bond between the building material and the mortar; the friction between the interlocking blocks of masonry is often strong enough to provide a great deal of strength on its own. The blocks sometimes have grooves or other surface features added to enhance this interlocking, and some dry set masonry structures forgo mortar altogether.

SEMI-INTERLOCKING MASONRY

STONEWORK Stone blocks used in masonry can be dressed or rough, though in both

examples: corners, door and window jambs, and similar areas are usually dressed. Stone masonry utilizing dressed stones is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Both rubble and ashlar masonry can be laid in coursed rows of even height through the careful selection or cutting of stones, but a great deal of stone masonry is uncoursed.

Slipform stonemasonry produces a hybrid wall of reinforced concrete with a rubble stone face.

Natural stone veneers over CMU, cast-in-place, or tilt-up concrete walls are widely used to give the appearance of stone masonry.

Sometimes river rock of smooth oval-shaped stones is used as a veneer. This type of material is not favored for solid masonry as it requires a great amount of mortar and can lack intrinsic structural strength.

Manufactured-stone, or cultured stone, veneers are popular alternatives to natural stones.

Manufactured-stone veneers are typically made from concrete. Natural stones from quarries around the world are sampled and recreated

using molds, aggregate, and colorfast pigments. To the casual observer there may be no visual difference between veneers of

natural and manufactured stone.

BRICKSolid brickwork is made of two or more wythes of bricks with the units running horizontally (called stretcher bricks) bound together with bricks running transverse to the wall (called "header" bricks). Each row of bricks is known as a course. The pattern of headers and stretchers employed gives rise to different bonds such as the common bond (with every sixth course composed of headers), the English bond, and the Flemish bond (with alternating stretcher and header bricks present on every course). Bonds can differ in strength and in insulating ability. Vertically staggered bonds tend to be somewhat stronger and less prone to major cracking than a non-staggered bond.

UNIFORMITY AND RUSTICITYMasonry repair work done to a brick wall.The wide selection of brick styles and types generally available in industrialized nations allow much variety in the appearance of the final product. In buildings built during the 1950s-1970s, a high degree of uniformity of brick and accuracy in masonry was typical. In the period since then this style was thought to be too sterile, so attempts were made to emulate older, rougher work. Some brick surfaces are made to look particularly rustic by including burnt bricks, which have a darker color or an irregular shape. Others may use antique salvage bricks, or new bricks may be artificially aged by applying various surface treatments, such as tumbling. The attempts at rusticity of the late 20th century have been carried forward by masons specializing in a free, artistic style, where the courses are intentionally not straight, instead weaving to form more organic impressions.

SERPENTINE MASONRYA crinkle-crankle wall is a brick wall that follows a serpentine path, rather than a straight line. This type of wall is more resistant to toppling than a straight wall; so much so that it may be made of a single Wythe of unreinforced brick and so despite its longer length may be more economical than a straight wall.