WALLS

A wall is a continuous, usually vertical structure, which is thin relative to its length and height. A wall is a
structure defining and exact area and providing safety and shelter. A wall can be external or internal. Walls
(as external) separate the internal built environment from the natural environment, creating a more
comfortable and conducive environment for humans. Walls (as internal) divide building into rooms or
compartments. The prime function of an external wall is to provide shelter against wind, rain and the daily
and seasonal variations of outside temperature normal to its location, for reasonable indoor comfort.
Walls can be made from masonry, timber, steel or concrete.

Walls with a primary function of resisting horizontal loads are called shear walls. Shear wall is a structural
member in a reinforced concrete framed structure to resist lateral forces and seismic forces. This type of
wall is needed in a larger houses or high-rise building. The taller the building, the greater the need for
internal shear walls and a lateral force resisting system.

Walls Classification

Load bearing wall: This wall is a structural element which supports loads from floors and roof in addition
to their own weight and which resist side pressure from wind and, in some cases, from stored material or
objects within the building, all the way to the foundation (usually strip).

Non-load bearing walls: These carry no floor or roof load. They are freestanding and carry only their own
weight, only meant for partition / division. Most of the time, they are interior walls whose purpose is to
divide the structure into rooms. One can remove any non-load bearing wall without endangering the
safety of the building. They are found in a framed structure.

Functional Requirements

The function of a wall is to enclose and protect a building or to divide space within a building; It provides
necessary resistance to rain penetration; It gives required degree of thermal insulation; It provides the
required degree of sound insulation to suit the building type; It provides sufficient openings for the
admittance of natural daylight and ventilation. The commonly accepted requirements of a wall are:

• Strength and stability

 • Resistance to weather and ground moisture
• Durability and freedom from maintenance
• Fire safety
• Resistance to the passage of heat
• Resistance to airborne and impact sound
• Security
• Aesthetics

Materials Used in the Construction of Wall

Some of the most popular materials that are used for walls are:

1. Stone, both natural and artificial (reconstituted) stone

2. Bricks and blocks, primarily of clay or concrete
3. Timber, used as a cladding and also in a structural capacity
4. Reinforced Concrete, used in a decorative and structural capacity
5. Steel, used primarily in a structural capacity
6. Glass, used as a rainscreen and also in a structural capacity

Masonry Walls

Stone, Brick, and concrete block walls are masonry walls.

Masonry is the simplest of building techniques: The mason stacks pieces of material (bricks, stones, or
concrete blocks, collectively called masonry units) on top one another to make walls.

Mortar

Mortar is as vital a part of masonry as the masonry units themselves. Mortar serves to cushion the
masonry units, giving them full bearing against one another despite their surface irregularities. Mortar
seals between the units to keep water and wind from penetrating; it adheres the units to one another to
bond them into a monolithic structural unit; and, inevitably, it is important to the appearance of the
finished masonry wall.
The most characteristic type of mortar is cement–lime mortar, made of portland cement, hydrated lime,
an inert aggregate, and water. The aggregate, sand, must be clean and must be screened to eliminate
particles that are too coarse.

Damp-proof courses (dpcs)

The function of a damp-proof course (dpc) is to act as a barrier to the passage of moisture or water
between the parts separated by the dpc.

There should be a continuous horizontal dpc above ground in walls whose foundations are in contact with
the ground, to prevent moisture from the ground rising through the foundation to the wall above ground,
which otherwise would make wall surfaces damp and damage wall finishes. The dpc should be continuous
for the whole length and thickness of the wall and be at least 150 mm above finished ground level to avoid
the possibility of a buildup of material against the wall acting as a bridge for moisture from the ground.
DPC materials are as follows: Lead, Copper, Polythene sheet, Bitumen, Polymer-based sheets, etc.

Stone Masonry

Stone masonry and concrete masonry are similar in concept to brick masonry. Both involve the stacking
of masonry units in the same mortar that is used for brick masonry. However, there are important
differences: Whereas bricks are molded to shape, building stone must be wrested from quarries in
rough blocks, then cut and carved to the shapes that we want.

Building stone is obtained by taking rock from the earth and reducing it to the required shapes and sizes
for construction.

Natural stones

The natural stones used in building may be classified by reference to their origin as:

• Igneous rock is rock that was deposited in a molten state, such as granite and basalt.
• Sedimentary rock is rock that was deposited by the action of water and wind, such as limestones
and sandstones.
• Metamorphic rock was formerly either igneous or sedimentary rock, such as slates and marble.
Natural stone has been used in the construction of buildings because it was thought that any hard,
natural stone would resist the action of wind and rain for centuries. Many natural stones have been
used in walling and have proved to be extremely durable for a hundred or more years. There have been
some failures of natural 144 Barry’s Introduction to Construction of Buildings stone due to a poor
selection of the material, poor workmanship and/or poor detailing.

Reconstituted (reconstructed) stone

Because natural stone is an expensive material, various artificial stone products have been developed as
alternatives. Cast stone is one of the terms used to describe concrete cast in moulds to resemble blocks
of natural stone. Reconstructed stone is made from an aggregate of crushed stone, cement and water.
The stone is crushed so that the maximum size of the particles is 6 mm and it is mixed with cement in
the proportions of one part cement to three or four parts of stone.

Types of Stone Walling

1. Rubble Walling

Rubble walling has been extensively used for agricultural buildings in towns and villages in those parts of
the country where a local source of stone was readily available. The various forms of rubble walling may
be classified as random rubble and squared rubble.

a) Random rubble

Uncoursed random rubble stones of all shapes and sizes are selected more or less at random
and laid in mortar

Random rubble brought to course is similar to random rubble uncoursed except that the stones
are selected and laid so that the walling is roughly levelled in horizontal courses at vertical
intervals of from 600 to 900 mm
 Figure 1.1: (A) uncoursed random rubble; (B) – coursed random rubble

b) Squared rubble

Squared rubble uncoursed is laid with stones that come roughly square from the quarry in a
variety of sizes. The stones are selected at random, are roughly squared with a walling hammer
and laid without courses

Squared rubble brought to course is constructed from roughly square stone rubble, selected and
squared so that the work is brought to courses every 300 to 900 mm intervals

Figure 1.2: (A) Uncoursed squared rubble; (B) coursed squared rubble
 2. Polygonal walling

Stones that are taken from a quarry where the stone is hard, have no pronounced laminations and come
in irregular shapes that can be laid as polygonal walling.

Figure 1.3: Polygon Walling

3. Flint Walling

Flint walling is built with a dressing of stone or brick at angles and in horizontal lacing courses that level
the wall at intervals.

Figure 1.4: Flint walling

Bricks Masonry

The word ‘brick’ is used to describe a small block of burned clay of such size that it can be conveniently
held in one hand and it is slightly longer than twice its width

Figure 1.5: Brick

Bricks can also be made from sand and lime or concrete. Glass bricks and blocks are also widely
available. Among the masonry materials, brick is special in two respects: resistance and size. A
traditional brick is shaped and dimensioned to Þ t the human hand. Hand-sized bricks are less likely to
crack during drying or firing than larger bricks, and they are easy for the mason to manipulate.

Types of brick

a) Clay bricks

Clay differs quite widely in composition from place to place and the clay dug from one part of a field
may differ from that dug from another part of the same field. Clay is ground in mills, mixed with water
to make it plastic and then moulded, either by hand or machine, to the shape and size of a brick.

b) Calcium silicate bricks (sand-lime)

Calcium silicate bricks are generally known as sand-lime bricks. The bricks are made from a carefully
controlled mixture of clean sand and hydrated lime which is mixed together with water, heavily
moulded to brick shape and then the moulded brick is hardened in a steam oven. The resulting bricks
are very uniform in shape and colour and are normally a dull white

c) Concrete bricks

Concrete bricks are manufactured in the same size as clay bricks. They tend to be more consistent in
shape, size and colour than clay bricks and come in a variety of colours and finishes. Appearance and
properties vary between manufacturers, although the concrete brick does have a different appearance
from clay bricks, which extends the choice to the designer.

Bonding

Bonding helps the wall acts as a whole so that the load of a beam carried by the topmost
brick/block/stone is spread to the two bricks below it, then to the three below that and so on down to
the base or foundation course of bricks.

Types of bond

a) Stretcher bond

The four faces of a brick, which may be exposed in fair face brickwork, are the two, long, stretcher faces
and the two header faces

Figure 1.6: Brick faces

The bricks are laid on bed with every brick showing a stretcher or the longer face on each side of the
wall, hence we have a stretcher bond. If it happens that we have a header face showing on the course
then it is known as header bond.

Figure 1.7: Stretcher bond

b) English bond:

In English bond the header face is centrally above and below the stretcher face i.e., the bricks in one
course or layer shows their header faces in the courses below or above their stretcher face. This bond
avoids the repetition of header faces in each course by using alternate courses of header and stretcher
faces with a header face lying directly over the center of a stretcher face below.

c) Flemish Bond

The bond has header faces being laid directly above and below a stretcher face
 Figure 1.8: Header bond, Flemish bond and English bond

Blocks and blockwork

Building blocks are wall units, larger in size than a brick, which can be handled by one person. Building
blocks are made of concrete or clay.

Concrete Blocks

These are used extensively for both loadbearing and non-loadbearing walls. A concrete block wall can be
laid in less time and may cost up to half as much as a similar brick wall.

Concrete blocks are manufactured from cement and either dense or lightweight aggregates as solid,
cellular or hollow blocks. A cellular block has one or more holes or cavities that do not pass wholly
through the block and a hollow block is one in which the holes pass through the block. The thicker
blocks are made with cavities or holes to reduce weight and drying shrinkage. Concrete blocks are laid in
stretcher bond.

Figure 1.9: Concrete blocks

PARTITION WALLS

It is an internal wall which is constructed to divide the spaces in an enclosed building into rooms or areas.

Internal walls may either be loadbearing or non-loadbearing. Non-loadbearing walls are usually referred
to as ‘partition’ walls, although care is required because the term is used very loosely. In loadbearing
masonry construction, the internal walls were usually constructed from brick or blockwork, although more
recently the trend has been to use stud walls made of timber or metal, which are quicker to erect and
easier to move at a future date.

Functions of Partition Wall

• Divide the inside of a building into rooms and spaces

• Divide a building into separate occupancies
• Separate adjoining properties
• Sometimes help to support loads if it is so designed.

Types of Partition Wall

a) Party Wall: is a wall separating adjoining building belonging to different owners or occupied by
different persons.
b) Separating wall: A wall that separates different occupancies within the same building.
c) Curtain wall: A self-supporting wall carrying no other vertical wall load, but subjected to lateral
forces.

Timber Stud Partition

Timber stud partitions are used in upper floors of domestic buildings and they are generally constructed
of 100mm x 75mm head and sill with vertical members called stud ranging from 75mm x 38mm, 100 x
50mm frame between them at about 400mm centre to centre.

The horizontal member known as Noggin piece are usually inserted between studs to stiffen the partition
plaster board. It is generally nailed to either side and finished with rose headed galvanized nails, stud
partitions of upper floors are usually supported by floor joist.

Advantages of timber partition walls

• Light weight in construction

• Ease of erection and dismantling
• Ease of alteration of space if need arises
 Figure 1.10: A typical timber stud partition wall

Figure 1.11: Method of jointing in Timber stud partitions