A dark brown to black cementitious material in which the predominating constituents are bitumens, which occur in nature or are obtained in pet
roleum processing.Asphalt is a constituent in varying proportions of most crude petroleum and used for paving, roofing, industrial and other special purposes.
PHYSICAL AND CHEMICAL PROPERTIES
Asphalt is obtained from fractional distillation of petroleum.
Felt used for paper. This felt is saturated with asphalt shingles and sidings which is used as roofing.
Stabilizers like silica, marble, sandstone etc. are combined with asphalt to control its hardness, elasticity, adhesion and weatherability.
Fine surfacing materials like talc, mica are finely ground and used to prevent the various asphalt materials from sticking together when packed.
Colored granules like natural slate, marble, granite are crushed, screened and graded to sizes.This is used to produce permanent colors.
CATEGORIZATION
Asphalt roofing is categorized as:
Organic
Fiberglass
Fiberglass based asphalt shingles are manufactured with mat composed entirely of glass fibers of varying lengths and orientations. This fiber glass base is then formulated with a special asphalt coating.
TYPES OF ASPHALT ROOFING
There are 6 types of Asphalt roofing .
Surfaced rolls produced from surfaced products.
Sidings.
Strip shingles.
Individual shingles.
Smooth roll roofing from saturated felts.
Built up roofing.
ROLL ROOFING
The wood deck is first cleaned first from any dust.
Hot or cold Asphalt cement as recommended by roofing manufacturer is poured.
The starter strip which is 914 mm wide and has lengths of 43.89 & 21.95.
The strip is then nailed to the deck in 2 rows, which are staggered, and in each row the nails have cc of 304 mm.
The nailing is done on the top of the roll on an offset of 120.65 mm.
The overlapping portion on the starter strip is covered with Asphalt cement.
Then the next roll is laid on the Asphalt cement.The roll overlaps on the starter strip by a distance of 482.6mm.
This strip is also then nailed in the same way.
Roll roofing can also be laid vertically in the same fashion.
Types of roll roofing
STRIP SHINGLES
The wooden deck is first cleaned of dirt and dust.
Felt underlayment is then laid on the wooden deck.
Underlayment is provided to low,sloping roofs.The roll roofing is laid on the deck in the same way as shown above.
The tabs used for the roofing is equal to three shingles.
The starter course or course of full 3-tab shingles reversed is laid and nailed on the underlayment.
The first course is then nailed and then further courses are nailed.
Each course covers the nails of the course below it,giving it a finished appearance.
Care is taken that the edges of the tabs are staggered
This type of roofing is used for slopes of 3to 12 up to 4 to 12
INDIVIDUAL SHINGLES
· The wooden deck is cleaned.
· Felt underlayment is laid, the felt underlayment is in roll roofing.
· Then the starter course of individual shingles is laid and nailed horizontally.
The starter course, which is horizontally laid on quick setting roofing cement and a starting course of quick setting cement in the vertical manner is also laid.
The next courses are laid and nailed staggering to the previous course.
Individual shingles are also found in hexagonal staple down shingles, which give a better aesthetical view and even Dutch lap shingles are also available which are kept in place by L type nails.
This type of roofing is used for roofs with pitch 4 to 12 up to 8 to 12.
Interlocking individual shingles
BUILT-UP ROOFING
· Built up asphalt roofing consists of alternate layers of hot asphalt cement and asphalt saturated felts.
· These layers are called 3-ply, 5-ply, etc., according to the number of layers of asphalt-saturated felt.
· The finished surface consists of slag or various types stone chips.
· This type of roof is used for roof surfaces with a pitch not greater than 3 to 12.
· The life of 3-ply roofing is 10 years and for 5-ply roofing is 20 years.
5-ply built-up roofing
DISADVANTAGES
Deterioration begins early in product life-cycle as product sheds its protective granules
Susceptible to blow off in high winds
Scars easily when hot
Susceptible to mildew and moss
Environmentally unfriendly
Defects in organic shingles:
CUPPING
LOSS OF GRANULES
ADVANTAGES
Affordable Cost: Compared to other roofing products, asphalt shingles are relatively inexpensive.
Peace of Mind: Asphalt shingles have been around for over 100 years. They have a proven track record in our harsh climatic conditions.
Suitability: Asphalt shingles are available in a wide selection of sizes, styles and colours, suitable for most residential applications.
Warranty Coverage: Asphalt shingles are protected with warranty periods ranging from 20 years to Lifetime, which will suit any budget and needs.
User-Friendly: Experienced Do-It-Yourselfers can apply asphalt shingles successfully.
Low Maintenance and Easy Repairs: Other more expensive roofing products can require more maintenance, specialized tools, can be more difficult to repair and almost always require professional installation.
ADVANTAGES OF FIBERGLASS SHINGLES
Are more resistant to heat, which may cause blisters to form on softer organic shingles.
On most application, fiberglass shingles require the installation of an asphalt saturated felt underlayment.
Are more resistant to curling, which can happen with organic shingles after many years of service.
Roof assemblies covered with fiberglass shingles have a higher fire resistance rating than roof assemblies covered with organic shingles.
OTHER USES OF ASPHALT
Transportation - highways, railbeds for transit systems, airport runways
Recreational - running tracks, greenway trails, playgrounds, bicycle and golf cart paths, racetracks, basketball and tennis courts
Aquatic - fish hatcheries, reservoir liners, industrial retention ponds, sea walls, dikes and groins to control beach erosion
Residential - driveways, subdivision roads
Agricultural - cattle feed lots, poultry house floors, barn floors, greenhouse floors
Industrial - work sites, log yards, ports, freight yards, landfill ca
Waterproofing on roofs & tanks.
Used in tanking.
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