JS 3 (BASIC 9) BASIC TECHNOLOGY SECOND TERM WEEK 9

SECOND TERM: E-LEARNING NOTES

JS 3 (BASIC 9)

SUBJECT: BASIC TECHNOLOGY

SCHEME OF WORK

WEEK: NINE

DATE:

TOPIC: BUILDING

SUB-TOPICS:

• Roofing
• Simple Blue Print reading

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Roof

Roof is the top feature in a building structure which provides covering for the entire building and protect any internal decoration or fittings from the weather thereby rendering the house habitable. The roof of a building is supported by frame work of Ridges, Trusses, purling, Rafters, Eaves.

Roofs perform specific functions which include:

• Weather Resistance: The roof must be water proof and shield the house from the direct rays of the sun.
• Strength: The roof must be strong enough to be able to carry its own weight and the superimposed weight of wind, and foot traffic for a considerable length of time without failing.

Types of common roof

1. Hipped roof: the hip roof has four slanting surfaces from a peak known as ridge. The construction has a shortening effect on the length of the building visually. The hip roof is widely used for most houses in Nigeria.
2. Pitched roof: This is often called gable roof. This type of roof is very common because it can be constructed easily. A typical characteristic of pitched roof is a cavity wall at the gable end, and vent between the fascia and soffit which prevents the rafter timbers from disintegration.
3. Shed roof: this is the simplest form of roof construction, having only one slope usually to the rear of the building. The overhang of the roof is usually greater at the front and the design has added simplicity and attractiveness to modern building construction.
4. Butterfly roof: this is double shed roof which slopes inwards with the low points to the centre of the building. It has a wide overhanging at the front and at the back which protects the walls from rains. It is mostly used where a large span is to be covered.
5. Monitor roof: the roof has two surfaces on either side of the house, with the lower one and vents or lightning spaces fixed vertically between them. It is commonly used for large factory buildings or warehouses.
6. Half Monitor roof: this roof has two surfaces only. One surface is lowered on one side while the other is raised a little above the lower one in the centre. The gap between the upper and lower central edges of the roof along the length is usually fitted with ventilation devices for roof members.
7. Combination roof: this roof has two surfaces sloping away more on one side than on the other. The greater slope is usually on top of the rooms while the smaller slope usually covers the veranda portion of the house. It is mostly used in school building construction.
8. Arched roof: this type of roof is usually used for large span construction work. The top is rounded and most economical in timber consumption. It could be made in the workshop and ready for fixing on the site.
9. Mansard roof: Mansard roof has double slopes on each side. Although not common nowadays, mansard roof allows the use of the space in the roof area. The lower part of the roof which is fitted with dormer windows has a steep pitch, while the upper part has a slope of about 30˚.

diagram

Diagram

Roofing materials: grass, zinc, corrugated aluminium sheets, wood, steel, concrete or clay, slates, plain tiles, corrugated iron sheets, corrugated asbestos cement sheets.

Diagram

Evaluation:

i. What is a roof?

ii. Mention five types of roof.

iii. Mention six roofing materials.

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Simple blue print reading.

EVALUATION

• What is blue print drawing?
• Draw the building symbols for sink, bath, showers, socket, door

WEEKEND ASSIGNMENT

• Move round the school premises and identify the type of roof used and the roofing materials.