IFFERENT METHODS of PITCHED ROOF CONSTRUCTION

Pitched roofs can be built in different ways depending on the loads and sizes. This list describes some common types of pitched roof that use different methods of construction.

Couple roof A couple roof has two timbers (called rafters) that are joined at the apex at their top end and rest on the walls at their bottom end. A couple roof is used for small spans.
Closed couple roof In a closed couple roof a tie member connects the bottom ends of the rafters. The design stiffens the rafters to resist the loads on a larger span.
Collar roof The collar roof has a tie member to connect the rafters higher up the slope. The design allows the roof eaves to be lower or the ceiling to be higher.
Purlin roof A purlin roof has a horizontal timber that is supported by the external walls of the roof structure to stiffen the rafters. The purlin may be supported by struts, which rest on internal load-bearing walls.
Trussed purlin roof Trusses replace struts as support for the purlins. Trusses, which are spaced about 1800 mm apart, are braced against external walls rather than internal load-bearing walls.
Trussed rafter roof A trussed rafter roof combines ceiling joists with additional struts and ties for larger spans. The trussed rafters, which are prefabricated, are braced against the external walls. The use of trussed rafters eliminates the need for purlins and other supporting members.

21 Topics for projects and presentations:

1. Metal roofing.

2. Defects of roofing.

3. Solar roofs.

4. Roof gardens.

5. Roof garden vs. green roof.

 

“Traditional buildings have thick exterior walls.

Modern buildings have thin walls.”

Matthew Frederick (architect)

WALLS

Unit 10

10.1 Types of Walls

1 Explain how the following words are connected with “walls”:

internal, external, load-bearing, non-load-bearing, cladding, separation, sound insulation.

 

2 Match information to the pictures:

1. It is a series of stone and earthen fortifications built originally to protect the northern borders of the Empire.All the walls measure 8, 851.8 km. This is made up of 6, 259.6 km sections of actual wall, 359.7 km of trenches and 2, 232.5 km of natural defensive barriers such as hills and rivers.

2. Known also as the Western Wall, it is located in the Old City of Jerusalem at the foot of the western side of the Temple Mount. It has been a site for Jewish prayer and pilgrimage for centuries.

3. It is a defensive wall that surrounds the Kremlin, recognizable by the characteristic notches and its towers. The original walls were likely a simple wooden fence with guard towers built in 1156.

4.It was a barrier constructed in 1961 that completely separated the country. The barrier included guard towers placed along large concrete walls, which circumscribed a wide area (later known as the " death strip") that contained anti-vehicle trenches, " fakir beds" and other defenses. The fall of the Wall paved the way for country reunification, which was formally concluded on 3 October 1990.

5. The wall is in Prague, Czech Republic. Once a normal wall, since the 1980s it has been filled with graffiti and pieces of lyrics from Beatles songs. Today, the wall represents a symbol of youth ideals such as love and peace.

6.It was a defensive wall first built by the Romans around Londinium, their strategically important port town on the River Thames. Until the later Middle Ages the wall defined the boundaries of the City. Today all that remains of the wall are a few fragments, some of which can be seen in the grounds of the Museum of London, in the Barbican Estate and around Tower Hill.

 

a ) The Kremlin Wall	b) The Great Wall of China	c) The Berlin Wall
d) The Lennon Wall	e) London Wall	f) The Wailing Wall

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Even walls may have ears. (Russian proverb)

To preserve friendship, one must build walls. (Italian proverb)

3 Discuss the following:

 

• Write a paraphrase. • Say whether you agree or not, and why.

READING

4 a) Transcribe the following words:

areas, characteristics, strength, thermal, durability, domestic, corrugated, insulation, reasonable, majority.

b) In what context do you think the following words and phrases will appear in the text?

•enclose and separate•external and internal •weather resistance •thermal properties •fire-resistance•load-bearing/ non-load-bearing •domestic •cladding sheets •separation •sound insulation

c) Read the text and check your answers:

WALLS

Walls are constructed to enclose areas and to separate the spaces inside and outside a building. This unit describes the main characteristics of external and internal walls.

External walls should have the following characteristics:

1) strength to resist being crushed by the loads from floors and roofs;

2) stability to resist other forces such as wind pressure and roof loads;

3) weather resistance to keep out wind and rain;

4) thermal properties to keep the interior cool in hot weather and retain warmth in cool weather;

5) durability;

6) fire-resistance to provide security and stability in the event of fire;

7) openings for daylight and ventilation;

8) good construction and use of materials.

External walls can be divided into the load-bearing external walls and non-load-bearing external walls.

Load-bearing external walls (Figure. 10.2) are normally used for domestic buildings or other small structures that are one or two storeys high. The weight of the roof and any upper floors is supported by load-bearing masonry of brick, block or stone construction.

Figure 10.2 Load-bearing external walls

Non-load-bearing external walls (Figure.10.3) are often built from corrugated sheet cladding that is attached to a framework of timber or steel rails and column. The cladding sheets do not support the structure of the building. Support is provided by the framework. The cladding sheets must be wind-resistant.

Figure 10.3 Non-load-bearing external walls

Internal walls should have the following characteristics:

1) positions that provide separation between rooms;

2) sound insulation that provides a reasonable level of noise control between adjoining rooms;

3) stability to resist normal impact and to support fixtures and fitting;

4) fire-resistance to prevent the rapid spread of fire to adjoining rooms.

Internal walls can be divided into the load-bearing internal walls and non-load-bearing internal walls (Figure 10.4).

Figure 10.4 Load-bearing and non-load-bearing internal walls

Internal walls are load-bearing if additional support is needed for the roof or floors. These walls will need to be strong and stable. They usually stand on concrete foundation.

Non-load-bearing internal walls divide the internal space in buildings and stand independently of the main structure. The majority of internal walls are in this category.

 

4 Read the text again and answer the questions that follow (1-7):

1. What characteristics of external walls can you offer?

2. How can you classify external walls?

3. What is the function of load-bearing external walls?

4. What is the role of sheet cladding in non-load-bearing external walls?

5. What are the characteristics of internal walls?

6. What have you learnt about internal load-bearing walls?

7. What types of walls divide the internal space in buildings?

Follow-up

6 a) Find in the text the synonyms for the following words:

principle features, to withstand, not allow to, thermic qualities, to hold warm temperature, small buildings, brickwork, plating, is ensured, acceptable rate of sound control, to obviate fast spreading, adjacent space, extra bearer/ bearing.