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BUILDING TECHNOLOGY

MORTARS AND PLASTERS

- a proportioned mixture of siliceous materials
(sand, crushed stone) and cement (lime, Portland)
which, after being prepared in a plastic state with
water,hardens into a stonelike mass.

1. MORTARS AND PLASTERS

• Mortar is cement mix used to glue masonry units
to each other, or other surface finishing materials
like tiles, bricks, stones to a receiving structure like
a wall or floor.
• Plaster is mortar applied to wall surfaces as a
preparation or a hard finish coat.

1.01 CEMENT MORTAR

- is a proportioned mixture of cement, fine
aggregate and water.
- For first-class mortars 1 part of cement should be
added to not more than 3 parts of sand.
- Replacing 10 or 15 percent of the cement by
volume with hydrated lime gives greater workability
and increases the strength of the mortar.
- For rubble stonework, 1 : 4 will be much stronger
than lime mortar.
- For the top surface of floors and walks, use 1 :
1 to 1-1/2.
- Mortar made with fine sand requires a much
larger quantity of cement to obtain a given strength
than mortar made with coarse sand.
- Mortar may be mixed by hand or mechanical
mixers, the latter being preferred for large
quantities.
- When the mixing is done by hand, it should be
done on platforms made watertight to prevent the
loss of cement.
- The cement and sand should be mixed dry in
small batches in the proportions required on a
clean platform.
- Water is added and the whole remixed until it is
homogeneous in color and leaves the mixing hoe
clean when drawn out.
- Mortar should never be retempered after it has
begun to set

1.02 PLASTER
- is a mortar of cementitious material ( lime,
gypsum or cement), sand and water which is
applied in coats (layers) to masonry surfaces, lath
or various types of plaster board to give a hard
finish surface to interior or exterior walls and
ceilings.
- the word “plaster” refers to gypsum plaster and
the words gypsum and plaster are often used
interchangeably.
- Fiber or hair is sometimes added to the mixture to
give increased strength as when used for the first
coat.
- Plastering is done according to two basic
methods: two-coat and three-coat.

A three-coat job consists of :

• a first binding coat called scratch coat;
• a second straightening coat called the brown-
coat; and
• a final coat called the finish coat.

In the two-coat work, the scratch and brown coats

are combined into one.

1.03 TYPES OF PLASTER AND THEIR USES

a. Lime Plaster
Lime putty (hydrated lime and water), mixed on the
job with sand and gypsum plaster, used for two and
three-coat finish surfaces for interior walls and
ceilings.

Scratch coat : 1 part lime putty, 1 part Portland

cement or Keene’s cement, 2-3/4 parts sand by
weight.
Brown coat : 1 part lime putty, 1part Portland
cement or Keene’s cement, 3 parts sand by weight.
Finish coat:
Hard finish : 1 part lime putty, 1/3 gypsum plaster by
volume
Sand float : 1 part lime putty, ¼ gypsum plaster, 2
parts sand by volume

b. Gypsum Plaster
• Gypsum plaster. Plaster of Paris mixed with clay,
lime and other materials in combinations covered by
trademarks or patents. Mixed on the job with water,
sand, lime putty, hair or fiber for two or three-coat
finish surfaces for interior walls and ceilings; or
used dry as ingredient for hard or sand float finish
with lime plaster (see above).

• High-strength gypsum plaster. Same as

gypsum plaster but mixed to meet established
standards. Mixed on the job with water, sand, lime
putty, hair or fiber for two and three-coat finish
surfaces for both exteriors and interiors.
- Scratch and brown coats :
1 part high-strength gypsum plaster to 2 parts sand
by weight.
- Hard finish :
¼ lime putty to 1 part highstrength gypsum plaster
by volume

• Fibered gypsum plaster. Gypsum plaster

premixed with fibers. Mixed on the job with water
and sand for scratch coat for three-coat plastering
job

• Prepared gypsum plaster. Gypsum plaster

mixed with fine white sand. Used for two and three-
coat finish surfaces for interior walls and ceilings .
- Scratch and brown coats :
mix per manufacturer’s instructions.
- Finish coat:
Any type of final coat plaster
(gypsum, Keene’s cement, lime or prepared finish
coat

• Bonding plaster. Gypsum plaster mixed with

ingredients develop more adhesive strength in
combinations covered by
trademarks or patents. Used for interior finish for
smooth concrete walls or ceilings. Mix and apply as
per manufacturer’s directions

• Lightweight gypsum plaster, fire-resistant

plaster. Gypsum plaster mixed on the job with
water, perlite, vermiculite or other suitable mineral
aggregate. Lightweight gypsum plaster is used
when weight is important, and for fire-proofing other
materials such as steel. Applied on lath. For
interior use only .
- Scratch and brown coats :
2 sand, 2 cu. ft. perlite or vermiculite per 100 lb. of plaster.
- Brown coat:
3 sand, 3 cu ft. perlite or vermiculite per 100 lb. of plaster.
- Finish coat:
Hard finish:
1/3 gypsum plaster, 1 lime putty by volume
Sand Float Finish:
1 gypsum plaster, 1-1/2 sand by volume

• Keene’s cement. Plaster of Paris mixed with alum

or borax or other materials and burned (calcined) at
932F. Mixed on the job with water, lime putty and
fine white sand as hard finish for two and three-coat
gypsum plaster. For interior use only
- Hard finish :
1 Keene’s cement, ¼ lime putty, 1/10 fine white
sand by weight .
- Sand float finish :
½ Keene’s cement, 2 lime putty, 4 ½ sand by
volume.

• Plaster of Paris. For ornamental plaster work and

castings.
• Molding plaster. For ornamental plaster work and
castings. Mix with water as per manufacturer’s
directions.

• Acoustics plaster. For acoustic treatment of

interior walls and ceilings. Applied on gypsum
plaster base coats. Mix with water as per
manufacturer’s directions.

c. Portland Cement Plaster

• Mixed with water, sand and lime putty. Used for
two and threecoat finish surfaces for exterior and
interior walls and ceilings
- Scratch and brown coats :
1 cement, ¼ lime putty, 3 sand.
- Sand float finish :
1 cement, ¼ lime putty, 3 sand.

• Thickness of plaster coats depends on the type of

material to which the plaster is applied. Generally,
the total thickness is 5/8” on metal lath and ½” on
lathing board and gypsum block.

• In three-coat plastering work, the scratch and

brown coats are ¼” thick at minimum; the finish
coat is 1/8” with a minimum of 1/16” at any point.

• For two-coat work, the base coat is ½” and the

finish coat is the same as three-coat work.

d. “Sgraffito”
• is highly decorative type of plaster work
developed in Italy during the Renaissance. This
type of technique consists of applying two or three
thin coats of plaster different colors and then cutting
away certain areas of one or two coats to produce a
three-dimensional colored design.

2.01 DEFINITION
Masonry - is a built-up construction or combination
of building materials as clay, concrete, or stone set
in mortar; or plain concrete.

Masonry Terms:
a. Bed – The horizontal surfaces on which the
stones or bricks of walls lie in the courses.
b. Course – A continuous layer of bricks, stones, or
other masonry units
c. Wythe or Tier – Each continuous, vertical
section of the wall, one masonry unit thick.
d. Bond – That connection between bricks, stones
or other masonry units formed by lapping them
one upon another carrying up the work, so as to
form an inseparable mass of building, by preventing
the vertical joints falling over each other (also
called a breaking joint).
e. Stretcher – A brick or block masonry laid
lengthwise of a wall
f. Header – A brick or block masonry extending
over the thickness of the wall
g. Heading course – A course in which the bricks
or other masonry units are all headers.
h. Soldier – A unit laid on its end with its face
perpendicular to the face of the wall.
i. Quoins – The corner stones at the angles of
buildings, usually rusticated so as to project from
the normal surface of the wall.
j. Bond Stones – Stones running through the
thickness of the wall at right angles to its face, in
order to bind it together.
k. Blocking or Blocking Course – A course of
stones placed on top of cornice crowning the walls

2.02 STONE
- Stone, together with wood and clay, are the basic
building material of man. The history of architecture
until as late as 1900 was largely the history of stone
in architecture,
- Stone was the structural material, the exterior and
interior finishing material, the flooring material and
in many cases the roofing material.
- It was also used for all types of sculpture, statuary,
and decorative and ornamental applications.
- Today, stone is largely used as a surface
finishing material for both the exterior and
interior of buildings.
- Stone commonly used for architectural
purposes include;
granite
marble
travertine
limestone
sandstone
slate.

They are commonly classified as:

a. Rubble Stone. Stone delivered from the quarries
rough and irregular shape.
b. Dimension Stone. Stone cut into specific size,
squared to dimensions, and to a specific thickness

STONEWORK: The types of stonework are based

on the shape and the surface treatment of finish of
the stone :
a. Rubble work. Masonry of rough, undressed
stones. When only the roughest irregularities are
knocked off, it is called scabbled rubble, and when
the stones in each course are rudely dressed to a
nearly uniform height, range rubble .
b. Random work. Stones fitted together at random
without any attempt to lay them in course.
c. Ashlar. Squared stones in regular courses, in
contradistinction to rubble work .
• Ranged work or coursed ashlar – Uniform
courses with stones uniform in size.
• Broken range ashlar – Course laid with the
horizontal joints uninterrupted but the width of the
courses and the length of the stones are varied to
produce a wall with a less regular pattern.
• Random course their rectangular shape and are
laid on horizontal beds but no effort is made to
continue the horizontal beds through in an
uninterrupted manner. Large stones combine with
small ones in a convenient and, if possible, an
interesting manner.
• Rustic or Rock work - Courses of stone face
which is jagged, so as to present a rough surface.
* Rustication occurs when heavier stones or areas of
stone project from the normal face of the surrounding wall
or of the joint themselves
2.03 BRICKS
- are structural units of clay or shale formed while
plastic and subsequently fired.
- The manufacture of brick consists essentially of
screening, grinding, or working the clay to the
desired consistency for moulding, whether by hand
or machine.
- After moulding, the bricks are dried and then
burned in kilns for many hours at high
temperatures, approximately 2000F.
- These processes purify the raw products, make it
uniform and homogeneous, burn out all combustible
matter, and result in a product which is both stable
and physically permanent .

The types of bricks most frequently used in

architecture are :
a. Common or building brick. Used for all
purposes, including facing.
b. Facing brick. Specially processed to give certain
specific surface characteristics. Used for exposed
masonry surfaces.
c. Glazed brick. These have a smooth outer
surface with a dull satin or high gloss finish. They
are load bearing, fire resisting, and impervious.
They are usually formed with vertical hollow
cores through the body with scoring on the back.
d. Fire (refractory) brick. These are ordinarily
made from a mixture of flint clay and plastic clay,
and are used for the lining of furnaces, fireplaces,
and chimneys.
BRICK WORK. The usual methods of laying brick
are as follows :
a. Common Bond. Consists of five stretcher
courses and then a header course. It is generally
begun with a row of headers at the bottom course
b. English Bond. Consists of alternate courses of
stretchers and headers .
c. Flemish Bond. Consists of alternate headers
and stretchers in each course .
d. Herringbone. The bricks are laid diagonally to
form a herring bone pattern.

Mortar joints between brick courses are usually

from 4.5mm (3/16”) to 12mm (½”).

2.04 CONCRETE HOLLOW BLOCK

• Concrete Hollow Block (CHB) is a hollow masonry
unit, with two or three cells or cores, made of the
following ingredients: water, Portland cement, and
various types of aggregate such as sand, gravel,
and crushed stone.
• Lightweight concrete hollow blocks are also
manufactured with such aggregates as cinders,
expanded slag, expanded shale or clay. Expanded
blast furnace slag rates the highest in fire
resistance, and due to its cellular structure, has high
sound and thermal insulation quality.
• These are manufactured by machine-mixing the
ingredients, pouring the mix into molds, and curing
the block by air drying. A steam-and-pressure
curing process is also used which can produce
concrete hollow block in a few hours.
• Standard CHB sizes are from thicknesses of
100mm (4”), 150mm (6”) and 200mm (8”) x
height of 200mm (8”) x length of 400mm (16”).
• CHB of 100mm (4”) thickness should be used only
for interior partition walls where weather-
tightness is not required.
• The different types of concrete hollow block
include:
a. Stretchers
b. Headers
c. Corner blocks
d. Jamb blocks
e. Beam or lintel blocks

• Concrete hollow blocks should be laid on a full

bed of mortar with horizontal and vertical joints
10mm (3/8”) thick.
• Reinforcement for 100mm (4”) and 150mm (6”)
thick wall shall be 10mm vertical bars at 600mm
on centers and 10mm horizontal bars every third
course.
• Reinforcement for 200mm (8”) thick walls shall
be 12mm vertical bars at 600mm on center and
12mm horizontal bars every third course.
• All horizontal reinforcement shall be tied to the
vertical reinforcement at their intersections.
• Dowel bars should be placed into the piers,
columns, slabs, leaving 20 bar diameters exposed
to splice with the reinforcement of the hollow
blocks.
• Block cells with reinforcement are filled with
cement mortar.
• Concrete hollow block walls should have a
reinforced concrete lintel or beam block course
every twelfth course; and a concrete column
stiffener at every 4.80 meters length.

2.05 “DURISOL” BLOCK

- “DURISOL” block is lightweight block made from
fiber and cement.
- “DURISOL” block units are two-core, 100mm (4”)
or 150mm ( 6”) x 87mm (7- 1/2”) x 600mm (24”).
- Reinforcement shall be 10mm  vertical bars
at 720mm (36”) on center and at every 4th
course. Every 4th course should be a beam
block course. Cores shall be solidly filled with
cement mortar.

2.06 PLASTER BLOCK

- also known as gypsum partition blocks, are
usually made of gypsum, vegetable fibers as
binders, and reinforcement.
- used for lightweight, fire-resistant interior
partitions and for furring and fireproofing columns.
- Gypsum hollow blocks are manufactured in units
of 75mm (3”), 100mm (4”) or 150mm ( 6”)
thicknesses, x 300mm (12”) height x 700mm
(30”)
length.
- Gypsum solid block is manufactured only with a
50mm (2”) thickness.

2.07 STRUCTURAL CLAY TILE

- Structural clay tile are hollow masonry units, open
at two ends with interior webs or partitions 19mm
(¾”) to 25mm (1”) dividing the block into
longitudinal cells.
- In its manufacture, the various shapes of clay tile
are formed through special dies and then wire-cut
into the required lengths.
- It may have a smooth or scored (grooved) surface.

Structural clay tile is classified into:

a. Load-bearing wall tile. 300mm x 300mm x
300mm (12” x 12” x 12”)
b. Non-load bearing, fireproofing, partition, and
furring tile. 100mm (4”) or 125mm (5”) x 200mm x
300mm
BUILDING TECHNOLOGY I
1.TYPES OF METALS

1.01 ALUMINUM

• is a soft, nonmagnetic silvery metal

• characterized by its light weight (1/3 that of
iron,brass or copper)
• low melting point
• high thermal and electrical conductivity
(surpassed only by silver and copper)
• moderately high coefficient of expansion
• readily combines with oxygen to form
aluminum oxide, a transparent film that makes it
corrosion resistant
• is readily attacked by alkalis, hydrochloric acid
and other dilute acids.
• is subject to galvanic action and should
therefore be electrically insulated from direct
contact with metals other than zinc, cadmium,
magnesium and nonmagnetic stainless steel.
• is easily worked: can be hot or cold rolled,
extruded, forged, pressed, drawn, molded,
stamped, bent and shaped.
• can be riveted, bolted, welded, brazed and
soldered.

In architectural work practically all fabricated forms

of aluminum are used:
- rod
- bar
- extrusion
- casting
- sheet
- strip, etc.

Extrusion is the process of shaping material by

forcing it to flow through a shaped opening in a die.

Extruded material emerges as an elongated piece

with the same profile as the die opening.

However, these products are not fabricated from

pure aluminum but in alloy combination with iron,
silicon, copper, manganese, magnesium, zinc,
chromium and nickel in small quantities to give
strength and other desirable characteristics but
often reduces its corrosion resistance.

“Alclad” is a term applied to certain aluminum

products, refers to the protective coating (cladding)
applied, primarily for corrosion resistance, to thin
sheets of an alloy whose corrosion resistance has
been decreased by the constituents added to give
strength and other characteristics.

Cladding improves the appearance of the alloy. This

thin, integral cladding usually consists of pure
aluminum, magnesium silicide, or zinc alloys, with
or without manganese.

a. Types of Aluminum:

• ALUMINUM SHEET AND STRIP, used for

roofing,
flashing, gutter, etc
• ALUMINUM FOIL - rolled to a thickness of 0.005”
(above 0.005” it is technically considered to be
sheet), used mainly for thermal insulation and vapor
barriers. It may serve also as a surface finish
material when laminated to various sheet and board
materials. In this form it also supplies additional
insulation value to the sheet or board.
• CORRUGATED ALUMINUM. This is rigidized
sheet fabricated of special aluminum alloys
specifically developed for this purpose. It usually
consists of an aluminum alloy core of one type
clad with another, highly corrosion-resistant
aluminum roofing and siding
 STRUCTURAL ALUMINUM.
When aluminum is used as a structural material,
important factors, arising from its physical and
chemical characteristics, are considered:
- Aluminum can be extruded; therefore a structural
shape can be produced economically to meet the
specified structural design requirements.
- Very corrosion resistant aluminum alloys are
available; requiring no painting and the thickness of
sections can be reduced since a safety margin is
not necessary to cover loss of strength due to
corrosion.
- Aluminum is very lightweight material, hence
aluminum girders and columns show increased
efficiency with large bay spacing. However,
because the modulus of elasticity of aluminum
alloys is lower than steel, its means that buckling is
a possibility and should always be checked.
 ALUMINUM DOORS AND WINDOWS.
These are generally fabricated from extrusions and
rolled shapes.

 ALUMINUM PANELS AND SANDWICH

PANELS
are pre-fabricated units, generally manufactured:
- using dimensions of modular and non-modular
window-width for building exterior, and
- in 600mm, 900mm, and 120mm widths for interior
partitions and dividers.
Panels for the exterior of buildings primarily consist
of :
- an aluminum exterior facing which may be an
aluminum casting
- an extrusion or sheet material which has been
pressed, stamped or formed into specially design
shapes.
 ALUMINUM PANELS AND SANDWICH
PANELS
A sandwich panel comprises a system of
construction called skin construction.
A cellular core of aluminum or other material has
a skin of aluminum applied and bonded to both
sides, thereby forming a unified whole in which all
the components work as one.
Floor Panel
Wall Panel

 Ornamental aluminum
Many kinds of rods, bars, pipes, railings, fittings,
and special shapes are manufactured as stock
items for use in ornamental design of railings,
grilles, screens, etc.
 Aluminum Mesh and Wire Cloth are used for
fencing, particularly chain link fencing and insect
screening.

 Mechanical finishes - obtained by grinding

polishing, scratching, sandblasting, embossing, or
other treatment of the surface to achieve a desired
effect or to provide a base for other finishes.

 Chemical finishes - based on chemical reactions

with the aluminum surface to achieve one of the
following results:
(a) etching, cleaning, or polishing of the surface
to remove any oxide film or surface irregularity and
provide a design, a clean surface texture, or a
polished effect; and
(b) oxidizing the surface with aluminum or other
metallic oxides that protect the surface or serve as
a base for subsequent treatment, or both. Chemical
finishes permit only limited colors that are not as
satisfying as the color films obtained on
electrolytically-applied (anodized) oxide films.

b. Types of Aluminum Finishes:

 Electrolytic finishes Commonly referred to as

anodized finishes, these finishes are based on
the specific ability of aluminum to develop a
protective coating of oxide on its surface. The
coating formed may be transparent or opaque. It is
hard, yet when colored finishes are desired, it is
porous enough to absorb dyes until the final
treatment which seals the surface. Of the colors
used in anodic treatments, architectural gold has
proven to be one of the most stable from the
standpoint of fade resistance. Others are blue and,
more recently, brown and black

 Electroplating. Aluminum can be covered with a

protective or decorative film or another metal,
usually by electrodeposition. In the case of copper
and nickel, the coating should be complete and
unbroken; otherwise there will be galvanic action
which is destructive to aluminum.
 Porcelain or Vitreous Enamel. This finish forms
a hard, resistant surface. It is available in a broad
color range that creates a different feeling in that
colors are glassy, whereas anodic color is metallic
in nature.
 Paint. Paint, lacquer and enamel can be applied
as finishes to aluminum surfaces that have been
prepared by a suitable chemical treatment finish.
Lead base paints must not be used on aluminum.

1.02 IRON

Pure iron is
• tough,
• malleable silvery-white
metal that is
• soft and ductile as copper
• it is easily magnetized
• is the most magnetically permeable of the
metals
• it oxidizes rapidly in air and is readily attack by
most acids.
• can be hardened by heating and sudden
cooling
• and made more pliable or more workable by
heating and slow cooling.
• At very low temperatures is very brittle
• at red heat it is soft, and
• at white heat it can be welded.

As pure iron passes through these temperature

ranges, it undergoes changes in its structure and
properties that are vitally important in the
preparation of steel (an iron carbonalloy).

The commercial form in which iron is first prepared

is crude or pig iron. This impure form which
contains 3% to 4% carbon and varying amount of
phosphorous, silicon, sulfur, and manganese, is the
starting point from which all other kinds of iron and
iron alloys (or steel) are produced.
The key to the various types of iron and steel is
the carbon-iron relationship.

a. Cast Iron:
• is an iron-carbon alloy that contains more than
1.7% carbon
• is poured while molten into forms
• it can be easily cast into any shape, but it is too
hard and brittle to be shaped by hammering, rolling,
or pressing.
• Cast iron is used in the architectural field mainly
for piping and fittings, ornamental
ironwork,hardware, as the base metal for porcelain
enameled plumbing fixtures, and for miscellaneous
casting such as floor and wall brackets for railings,
vents, circular stairs manhole covers, and gratings.

• The types of cast iron generally used are gray cast

iron and malleable cast iron. Cast irons find their
largest use in heavy machinery and industry
because it has significant compressive strength and
the ability to absorb energy and stop vibration

b. Wrought Iron:
• is almost pure iron with less than 0.1% carbon,
usually not more than 0.05%.
• contains 2.5% of slag (iron silicate) in purely
physical association, not alloyed.
• Wrought iron is soft, malleable, tough, fatigue
resistant, and resistant to progressive corrosion.
• It has good machinability and can be forged,
bent, rolled, drawn, and spun. It can be welded by
any of the commonly used procedures. Wrought
iron is available in the form of pipes, plates,
sheets,special shapes, and bars
• Wrought iron is now used in the architectural filed
primarily in the form of genuine wrought iron pipe,
chain, sheet, and ornamental ironwork. Wrought
iron pipe is used extensively for plumbing, heating,
and air conditioning where a corrosion-resistant,
tough, durable material is required.

Because it is intrinsically related to classical

architecture and requires high skilled
craftsmanship, wrought ironwork today is used
only in furniture, railing, fences, grilles, and small
decorative objects.

1.03 STEEL
• The word “steel” refers usually to plain carbon
steels which is defined as alloys of iron and
carbon which do not contain more than 2% carbon
and which are made in malleable or ingot form.
• In the plain or straight carbon steels the iron is
always in excess of 95%.
• phosphorus, sulfur, oxygen and nitrogen are
present, the last three as impurities.
• Manganese, silicon, aluminum, copper and nickel
may also be present either as residual impurities
or as elements deliberately added in small
quantities to control the properties of the steel.
• Carbon steel can be wrought, rolled, cast, and
welded, but not extruded.

a. Wrought Carbon Steels:

 Structural steel.
This is a medium carbon steel with its carbon
content controlled to give both the strength and
ductility necessary for its use.

Structural steel is available in angles, channels, I-

beams, H columns, T shapes, Z shapes, plates,
round pipe columns, sheet piling, open web joists,
and light steel framing shapes.

 Reinforcement of concrete
.Usually deformed bars of varying grades and
diameters.
 Sheet and strip.
Steel sheet is made from low carbon steels
generally containing about 0.15% carbon and not
exceeding 0.25% carbon. Strip by definition is
sheet material that is 12” or less wide. It is used in
fabricated form as decking galvanized sheet,
expanded metal, panels and sandwich panels, and
as a base metal for porcelain enamel

 Corrugated steel.
This is rigidized sheet fabricated from low-carbon
cold or hot-rolled steel sheets which are either
galvanized or covered with some type of bituminous
coating. If galvanized, corrugated steel is silvery in
color and has a glittering frosted surface. It is
generally available in 18, 20, 22. 24, and 26 gauge
sheet and strip.

 Steel Mesh and Wire Cloth.

They are used for concrete reinforcement, lath
for plaster, stucco, and cement, fencing, insect
screens.

 Steel Windows and Doors.

 Hardware such as nails, screws, rivets, etc

b. Alloy Steels:
• steels to which manganese, silicon, aluminum,
titanium, and molybdenum have been added
insufficient quantity to produce properties
unobtainable in carbon steels in cast, rolled or
heat-treated form.
• The alloying elements are added to increase the
following properties:
 strength
 hardness
 ease and depth of hardenability
 performance at high or low temperatures
 electromagnetic properties
 wear resistance
 electrical conductivity or resistivity.
 electrical conductivity or resistivity.
 In structural applications only the properties of
 strength
 expansion
 resistance to corrosion
 ductility, and
 workability
 are of interest to the architect.

High-strength low-alloy steels

are a group of trade name steels with improved
mechanical properties and resistance to
atmospheric corrosion, They are being
increasingly used as reinforcing for pre-stressed
concrete, high strength bolts, special structural
steels and cables for elevators, etc.

 Stainless steels
generally used in architecture are highly alloyed
steels that contain more than 10% chromium. They
are characterized by their resistance to heat,
oxidation and corrosion. They are used where
corrosion resistance, durability, and minimum of
maintenance is necessary principally for exterior
and interior wall finishes, doors, windows, trims,
railings, signs and letters, appliances, etc.

1.04 COPPER
• is ductile, malleable, nonmagnetic metal with a
characteristic bright, reddish brown color.
• has the highest electrical and thermal
conductivity of any substances except silver.
• Copper useful alloys have enough strength for
minor structural work
• easily worked.
• It is attacked by alkalis and many of the
common acids.
• It is highly resistant to corrosion by air and salt
water.
• On exposure it soon reacts to form a surface
layer of an insoluble green slat which retards
further corrosion; this green color on copper is
known as its patina.
• Copper can be cast, drawn, extruded, hot and
cold worked, spun, hammered, punched,
welded, brazed, and soldered.
• The galvanic action of copper must be considered
when copper is used in architecture. When in
contact with many of the common construction
materials and in the presence of an electrolyte; it
will corrode these materials near the area of
contact.
• As copper is one of the best electrical
conductors, it finds tremendous used in the entire
electrical field, from very fine wires to bus bars.
• The copper itself, being cathode, will not corrode.
Therefore a careful check should be made of the
methods of attachment, support and securing into
place.
• Copper sheet and strip is used for roofing and
flashing.

1.05 TIN
• is a soft, ductile, malleable, bluish-white metal.
• Because it is normally covered with a thin film of
stannic oxide, it resists corrosion by air,
moisture, sulfur dioxide, hydrogen sulfide
(which usually tarnishes and corrodes other
metals).
• will take a highly reflective polish
• The main use of the tin is in metallic form of
either pure tin or tin-containing alloys for
protective coatings on stronger metals.
• Architectural uses of tin include bronzes,
brasses, terneplate, mirrors, gilding, solders,
hardware and fusible alloys.

1.06 ZINC
• is medium hard, bluish-white metal
• is characterized by brittleness and low strength.
• is readily attacked by acids and alkalis.
• It is resistant to corrosion by water. On
exposure to air, a film of zinc carbonate or oxide
forms which protects zinc from further oxidation.
• The most important uses of zinc are
as protective coatings (galvanizing) on iron and
steel as die-casting metal, and as an alloying
element in brasses
• Galvanizing is the process whereby a
protective coat of zinc is applied to steel and
iron to steel them against corrosion. The
advantage of coating them with zinc is that,
should the iron or steel become exposed through
wear, aging or discontinuities, galvanic reaction
between the coating and the base metal causes the
zinc to corrode and form compounds which cover
and continue to protect the iron and steel for as long
as any zinc remains.
• The most common galvanized material used in
architecture is galvanized iron (steel) sheet and
strip.
• available flat or corrugated with the surface plain
or refinished with other surface materials.
• Galvanized sheets become defaced and
discolored when subjected to dampness and
extremes of temperature.
• If the sheets are piled flat in the open or tightly
bundled in a warehouse, the zinc coating can also
be damaged by the consequent absence of oxygen
and carbon dioxide between two sheets. This
absence prevents the formation of a protective film
of zinc carbonate; instead zinc hydroxide forms and
destroys the galvanizing.

1.07 BRASS
• fundamentally an alloy of copper and zinc with
small quantities of other elements sometimes added
to give the special qualities.
• The copper-zinc proportions may vary from 95%
copper and 5% to 55% copper and 45% zinc.
• As a class, brass alloys are less hard and strong
than steels (iron-base alloys) but are superior in
workability and resistance to corrosion.
• All brasses react with other metals. When brass
is used in direct contact with any other metal, a
careful check should be made of its position on the
galvanic series.
• Brass should not come into direct contact with
iron, steel or stainless, aluminum, zinc or
magnesium if there is an electrolyte present or the
possibility of one forming at the point of contact.
• In architecture, brasses are used for doors,
windows, door and window frames, and for
ornamental metalwork such as railings, trims,
grilles, etc.
• They are also used extensively for finish
hardware, plating of hardware, and other
miscellaneous
accessories such as screws, nuts and
bolts,anchors, etc.

1.08 BRONZE
• True bronze is an alloy of copper and tin
which varies only slightly from 90% copper
and 10% tin composition.
• This bronze is a rich golden-brown metal
• originally worked by forging and particularly
suited for casting since it is corrosion resistant,
• dense and hard enough to take an impression of
a mold of any delicacy whatever.
• The term “bronze” however, is no longer used in
this limited sense. In commercial practice the terms
“brass” and “bronze” may be used without much
regard for their original meanings.
• The term “bronze” now usually has a prefix and
indicates alloys of copper with silicon, manganese,
aluminum, and other elements with or without zinc,
e.g. silicon bronze.
• A few brasses are known as bronzes because
they the characteristic bronze color.
• Of the three types of so-called bronzes in
architectural work, only one is true bronze. This is
the statuary bronze, which consist usually of 97%
copper, 2% tin and 1% zinc.
• As for the others, architectural bronze is really a
leaded brass, and commercial bronze is one of the
more commonly used brasses (90% copper and
10% zinc).
• The architectural uses of bronze are confined to
statuary plaques, medallions and other
ornamentation, and miscellaneous rough and
finish hardware.

1.09 CHROMIUM
Chromium is a steel-white metal which takes a
brilliant polish and is harder than cobalt or nickel.
It is nonmagnetic at ordinary temperatures but
becomes magnetic at 13F. It does not tarnish in
air, resists oxidizing agents, is soluble in
acids and strong alkalis.

The principal use of chromium is an alloying

ingredient in ferrous and nonferrous metallurgy.

Chromium plating is one of the most commonly

encountered usage of this material in architecture. It
gives a thin, hard, bright, wear resistant surface
which sheds water when highly polished. The
metals that can be plated with chromium include
aluminum, copper, iron, magnesium, nickel,
titanium, zinc and their alloys. The chromium is
electro deposited as a thin layer of pure metal.

1.10 NICKEL
When alloyed with other metals, nickel imparts its
qualities of strength, hardness, toughness, ductility,
corrosion resistance, and strength at high
temperatures to the resulting material.

The major use of nickel therefore is in alloys.

Another important use of nickel is as protective or

decorative coating for other metals. It can be
applied to the following base metals and their
alloys: aluminum, brass, copper, iron, magnesium,
steel, tin, and zinc.

Nickel is an inert silvery metal that is resistant to

strong alkalis and to most acids. It resembles iron in
strength and toughness and copper in its resistance
to oxidation and corrosion.

Nickel takes a high polish and can be hot and cold

rolled forged, bent, extruded, spun, punched and
drawn.

1.11 LEAD
Lead is a blue-gray, soft, very heavy metal (the
heaviest of the common metals). It is extremely
workable, has a good corrosion resistance, is easily
recovered from scrap materials, and is relatively
impenetrable to radiation. The corrosion resistance
of lead arises from the fact that metallic lead does
not react with many compounds or solutions, and
with certain others it forms compounds which act as
protective coatings against further corrosion.

Lead is available
(1) extruded in the forms of pipe, rod, wire, ribbon,
etc.
(2) rolled into sheet, foil, strip,
(3) cast.

There are several grades of lead metal which

corroding lead, chemical lead and common
desilverized lead are of interest to the architect.

Corroding lead is used for fine white lead paints,

red lead, litharge (see PAINT).
Chemical lead and common desilverized are
used for sheet, pipe, powdered lead, ribbon lead
and alloys.

Lead also finds many uses in rough hardware

items such as expansion shields for securing
bolts,screws, and other accessories in masonry,
washers, lead-headed nails,etc.1. TYPES OF METALS

2. METHODS OF JOINING METALS

2.01 SOLDERING
Soldering is a method to join metals, to make
electrical connections, to seal joints hermetically
them in with another, lower melting metal or alloy
called the solder.

Since the temperatures used are comparatively low,

there is no alloying action between the solder and
the metals being joined, which are usually stronger
than the solder itself.

Soldered joints have very little tensile, shear or

impact strength; therefore this method should not
be used where a strong joint is required.

Solders are mostly alloys of tin and lead in

various proportions with small percentages of other
elements added to give special characteristics.
They can be divided into the following major
types: tin-lead, tin-lead-antimony, silver-lead.

Tin-lead solder of the 50% tin, 50% lead variety is

the most commonly used general purpose of solder.
Some tin-lead are used for coating the metals
before soldering. This is known as pre-tinning.

a. Metal Bath Dip Solder:

Metal bath dip soldering is defined as a metal-
joining process where the workpieces to be
joined are immersed in a pot of molten solder.
Because of the relatively low melting temperature of
the solder (between 350 and 600 degrees F), only
adhesion between the solder and the workpieces
results. A flux or metal cleaner is used to prepare
the workpiece for bonding with the solder.
Typically, dip soldering is an automated process
used extensively in the electronics assembly
industry.

b. Soldering Iron:
In this method the iron piece is preheated and
applied to the joint along with the solder and the
flux (the flux is a substance used in soldering to
clean the surfaces of the metals to be joined and to
aid fluidity); the heat from the iron forms the
soldered joint.

c. Torch:
The parts to be soldered are heated by the torch
flame and then the solder and flux are applied. This
method is limited to metals which can be heated
without altering their characteristics.

d. Sweat Method:

Fluxes:
 Neutral fluxes are mild in type and are used for
easily soldered metals such as copper, brass, lead,
and tin plate. Stearic acid is a typical neutral flux.
 Noncorrosive fluxes leaves residues which are
noncorrosive and nonconductive and therefore
need not removed. Rosin is the principal flux of
this type.

Noncorrosive fluxes are weak their fluxing action

and their use is limited to the easily soldered base
metals.
2.02 BRAZING
Brazing is a type of soldering in which the
operating temperatures are higher (but lower than in
welding) and in which stronger and higher-melting
alloys are used to fill the joints, which
consequently are stronger than ordinary
soldered joints. The bond is obtained by allying
between the brazing material and the surface of the
joined metals.

Brazing is generally used where the shape and

position of the joint or the composition of the metal
or metals are not adaptable to welding. In brazing
the type of metal to be joined, the brazing material,
and their color are equally important because
galvanic action, strength of the joint, matching of
colors play a significant part in the finished product.

Brazing materials fall into six major types:

 aluminum-silicon
 copper-phosphorous
 Silver
 copper, and
 copper-zinc, magnesium, and heat-resistant
alloys.

Each type is particularly suited to a certain group of

metals.

The brazing materials are prepared by melting and

mixing together the metallic ingredients to fixed and
controlled proportions.
2.03 WELDING
Welding is the process by which two metals are
so joined that there is an actual union of the
interatomic bonds. This may be brought about by
close contact, heating, pressure, adding molten
metal, or combinations of these methods. The
resulting are as strong or stronger than the metals
joined.

Welding may be divided into two general types:

 pressure welding in which pressure and heat
make the weld; and
 fusion welding, in which the heat and added
metal make the weld. In fusion welding the methods
of heating are gas flame and electric arc.
 Two types of fusion welding:
• The gas flame now generally used is
acetylene mixed with oxygen. It will deliver
about 5500˚F of heat which is sufficient to melt
the welding rod and the surrounding metal and
then fuse them together.
• In electric-arc method, when the welding rod
(or electrode) is brought near the joint of the
metals to be welded, an electric arc is to be
formed which melts and fuses the metal and
the welding rod.

2.04 RIVETS
Rivets are devices used to join or fasten the
metals.

The rivet, a metal cylinder or rod which has a head

at one end, is inserted through holes in the
materials being joined, and then the protruding end
is flattened to tie the two pieces of material
together.

3. METALS FOR CONCRETE REINFORCEMENT

3.01 STEEL BARS

Reinforcement for concrete construction is
mostly in the form of steel bars and rods of round or
square cross section. The bars may be plain or
deformed (with lugs or projections for better
bonding to the concrete). They are called billet-
steel bars or rail-steel bars.

Billet-steel bars are made by the open hearth

furnace by the acid Bessemer furnace and meet
fixed chemical compositions. They are rolled from
billets directly reduced from ingots and come in
three grades: structural, intermediate, and hard.

For architectural purposes the intermediate grade

is the most generally used.

Rail-steel bars are rolled from standard T-rails and

come only in one grade. Steel bars vary in size from
¼” to 1-1/4” and in lengths of
20 or 30 feet.

3.02 WIRE FABRIC

Wire fabric made of cold-drawn steel wire is
widely used for the reinforcement of concrete slabs
and floors, as well as for stuccoed work
a. Welded Wire Fabric:
Welded-wire mesh, also called welded-wire fabric,
used to reinforce concrete slabs used in light
construction., consists of a series wires welded
together to form a grid pattern.

It comes in various sizes and spacings and gauges,

e.g. 4” x 4” – 6/6, 6” x 6” –8/8, etc. The first pair of
numbers refer to the spacing of the wires: the
second pair refers to the gauge of the longitudinal
and transverse wires respectively. Thus, for
example, a 6”x 6” – 10/10 mesh (read it six six –ten
ten) will be both No. 10 gauge wires spaced 6”
apart bothways (the smaller the gauge number the
heavier the wire).

Welded wire fabric is available in rolls 5 or 6 ft.

wide,
150, 200, and 300 ft. long.

b. Triangle-mesh Wire Fabric:

is built up of either single or stranded longitudinal
wires with cross wires or bond-wires running
diagonally across the fabric. The longitudinal
wires are spaced at 4” on centers and the cross
wires 4” or 8” apart.

3.03 EXPANDED MESH

This is manufactured from solid steel sheets.

To form the expanded mesh, the sheet is first cut or

pierced in staggered slots or patterns; then the
sheet is held by the two sides parallel to the slots
and stretched by pressure until the desired
openings or forms are obtained. Sheets may also
be stamped, perforated or deformed into an
open mesh. The forms into which sheet can be
shaped include diamond, crimp, herringbone and Z-
rib, to name only a few.

Expanded mesh is therefore free from

mechanical and welded joints., e.g.
STEELCRETE.

3.04 LATHS
In addition to the various meshes mentioned above,
permanent centering or self-centering laths are
produced in many forms. These laths are furnished
either in flat or segmental sheets, pressed into a
series of solid ribs, between which the metal is
stamped, perforated or deformed into an open
mesh-work. These laths are furnished painted or
galvanized, and in open-hearth mild steel or in
special copper-bearing or alloy steels, e.g.
“RIBPLEX”, “HYRIB”

4. STORAGE & CARE FOR METAL

REINFORCEMENT
Metal reinforcement shall be stored in racks
above the ground and away from moisture and
vegetation.

If a large quantity of reinforcement is stored at the

site for an extended period, it is well to build shed
over the storage racks.

A bright-red rust, such as forms in a few days on

reinforcement exposed to rain, is not in any way
detrimental. Actual rust scales, however, may
indicate a reduction in the effective cross section
of the bar.

Deep scaling should be considered a sufficient

reason for condemning the use of reinforce unless
it is first cleaned of mill and rust scale and used as
the equivalent of a smaller size.

All reinforcement should be kept free from oil

which will tend to reduce the bond between
concrete and steel.