BRICK LOADBEARING WALLS

ROOFS

Roof is an overhead building construction, performing carrying, waterproofing and heat insulation functions. Roofs have been constructed in a wide variety of forms as dictated by technical, economic, or aesthetic considerations.

Two main types of roofs are flat roofs and slanted or sloping ones. The flat roof has historically been widely used in the areas where the climate is dry and the drainage of water off the roof is of secondary importance. Flat roofs came into widespread use in Europe when new waterproof roofing materials and the use of structural steel and concrete made them more practical. Flat roofs soon became the most commonly used type to cover warehouses, office buildings, and other commercial buildings, as well as for many residential structures. Besides, the flat roof also performs other functions: it can serve as a solarium, a garden, a sport ground or even as a car park.

Sloping roofs come in many different varieties. The simplest is the shed, which has only one slope. A roof with two slopes that form an "A" or triangle is called a gable roof. This type of roof was used as early as the temples of ancient Greece and is still a very common form of roof. A hip roof is a gable roof that has slopes instead of vertical ends. It was commonly used in Italy and elsewhere in southern Europe and is now a very common form in American houses. Gable and hip roofs can also be used for homes with more complicated layouts. The gambrel roof is a two-sided roof with a central ridge. Each side has two sloping surfaces, the upper being less steep than the lower. The mansard roof is a four-sided gambrel-style hip roof characterized by two slopes on each of its sides.

The external covering of a roof must prevent rainfall or other atmospheric precipitates from penetrating a building. There are two main groups of roof coverings. One group consists of a waterproof film that repels water. The tar that is used to coat roofing felt is the prime example of this type. The other group consists of pieces of a waterproof material that are arranged in such a way as to prevent the direct passage of water through the joints between those pieces. This group includes shingles made of various materials, tiles made of clay or slate, and corrugated sheets of steel, aluminum, lead, copper or zinc.

Flat roofs are normally covered with roofing felt and tar, while sloped roofs are generally covered with shingles or sheet metal.

Ex. 2. Match the definitions with the appropriate words.

1. shed a) a type of gable roof with two slopes on each side,

the upper being less steep than the lower.

2. gable roof b) a roof which has only one slope

3. hip roof c) a hipped gambrel roof having two slopes on every side.

4. gambrel roof d) a roof with two slopes that form an "A" or triangle

5. mansard roof e) a gable roof that has slopes instead of vertical ends

Ex. 3. Find the answers to the following questions in the above text.

1. What are the functions of a roof?

2. What types are roofs divided into?

3. Where has flat roofs been widely used? Why?

4. What are the most common application of flat roofs nowadays?

5. What types of sloping roofs exist?

6. What is the aim of external roof covering?

7. What types of roof covering do you know?

8. What type of roof is usually covered with tar?

9. What kind of covering is used for sloping roofs?

Ex. 4. Look at the picture and define the type of each roof.

Ex. 5. Think of the best type of roof for:

v detached house;

v university building;

v block of flats;

v department store;

v skyscraper.

6. Read and translate the following text.

BRICK LOADBEARING WALLS

The external wall of a house has two basic functions:

• to support the loads of floors and roof,

• environmental protection.

In order to fulfil these functions there are a number of requirements for an external loadbearing wall. These are: strength and stability, weather protection, good thermal insulation, fire protection and durability.

The two most common materials used nowadays for walling in domestic construction are brickwork and block-work. The majority of bricks are made from clay. Different clays have different characteristics and, by using special manufacturing techniques and adding a variety of additives, bricks of various colours and strengths can be produced.

Bricks can be described as:

• common bricks - these are suitable for general building work where the face of the brick will be covered with plaster or other finish;

• facing bricks - these come in a wide range of finishes, colours and strengths and are used where the face will be left exposed. The most common use today is for the outside walls of houses;

• engineering bricks - these are dense bricks with high compressive strength and low rates of water absorption. Although some of them may be used as facing bricks for houses they are more likely to be found in civil engineering structures such as retaining walls and bridges.

Bricks can also be classified by their resistance to frost attack. Some bricks are totally resistant to frost attack while others are quite vulnerable. Bricks suitable for severe exposure are classified F2 (the new European Standard), those suitable for moderate exposure are classified F1, and those suitable for passive exposure FO. Class F2 bricks are therefore suitable for use in any part of an external wall including situations where they may be saturated and have to undergo repeated cycles of freezing and thawing. Class F1 bricks are normally durable in the outer face of a building as long as exposure is not severe and appropriate measures have been taken in the design of the wall to prevent saturation. Class FO bricks are generally for internal use only.

Calcium Silicate Bricks. These bricks are made from sand or crushed flint and lime together with coloured pigments. The materials are mechanically pressed into shape and then put in hardening chambers into which steam is injected under pressure. The bricks are very regular in shape and can easily be recognised by their pale colours. They are generally resistant to frost attack and virtually free from soluble sulfates.

Concrete Bricks. The majority of concrete bricks are made by blending and compacting dense aggregate with a binder under high pressure. Coloured facing bricks are manufactured by blending different aggregates or by adding special pigments.

Blockwork has become very popular in the last 60 years or so because of its cost advantages over brickwork. Most blocks are equivalent in size to six bricks (three bricks high and two long) and are available in a range of widths from 50 mm to 300 mm. Blocks less than 75 mm wide are unsuitable for loadbearing walls. Blocks are made from cement and aggregate, and by varying the quantity of cement and the nature of the aggregate, blocks with different strengths and levels of insulation can be formed.

Ex. 7. Say which of the following issues are considered in the text. If they are, say to which paragraphs they belong:

- advantages of blockwork, advantages of engineering bricks, bricks for external and internal use, comparison of brick classes, functions of the external walls, kinds of brick suitable for facing, practical values of different bricks, production and use calcium silicate brick, production of concrete bricks, requirements for loadbearing walls, sizes of concrete bricks, the components of brick.

Ex. 8. Arrange the sentences in the logical sequence of the text above.

A) Blockwork has cost advantages over brickwork.

C) Calcium silicate bricks are made from sand or crushed flint and lime.

D) Class F2 bricks may be saturated and undergo repeated cycles of freezing and thawing.

E) Class FO bricks are suitable for internal use only.

F) Concrete bricks are a mixture of dense aggregate with a binder.

G) Different proportions of cement can produce bricks of various strengths.

I) Engineering bricks are dense, with high compressive strength and low rates of water absorption.

L) Some bricks are totally resistant to frost attack while others are quite vulnerable.

N) The majority of bricks are made from clay.

O) The most common use of facing bricks is for the outside walls of houses;

P) There are a number of requirements for an external loadbearing wall.

Ex. 9. Text 1 has no conclusion. Suggest one or more sentences to conclude the description of the building material under consideration.

Ex. 10. Give summary of the text. For each of the parts give the key statement and support it with the chosen additional information.

Ex. 11. Insert into the sentences the right word or word group from the box.

Cost advantages; an external loadbearing wall; internal use; compressive strength; a variety of additives; binder; floors and roof; totally resistant; facing bricks; cement and aggregate; moderate exposure

1. To support floors and roof is one of the basic functions of the external wall of the house.

2. The basic requirements for an external loadbearing wall are strength and stability, weather protection, good thermal insulation, fire protection and durability.

3. By using special manufacturing techniques and adding a variety of additives, bricks of various colours and strengths can be produced.

4. Engineering bricks are dense bricks with high compressive strength and low rates of water absorption.

5. Some bricks are totally resistant to frost attack while others are quite vulnerable.

6. Bricks suitable for moderate exposure are classified F1.

7. Class FO bricks are generally intended for internal use only.

8. Concrete bricks are made from dense aggregate with a binder .

9. Coloured facing bricks are manufactured by blending different aggregates or by adding special pigments.

10. Blockwork has become very popular because of its cost advantages over brickwork.

11. Most blocks are made from cement and aggregate and have different strengths and levels of insulation.

Ex. 12. Complete the sentences.

1. In order to fulfil its functions the external loadbearing wall has such requirements as strength and stability, weather protection, good thermal insulation, fire protection and durability.

2. The majority of bricks are made from clay using special manufacturing techniques and adding a variety of additives, bricks of various colours and strengths can be produced.

3. Common bricks are suitable for general building work where the face of the brick will be covered with plaster or other finish.

4. Engineering bricks are dense bricks with high compressive strength and low rates of water absorption.

5. Class F2 bricks are suitable for use in any part of an external wall including situations where they may be saturated and have to undergo repeated cycles of freezing and thawing.

6. Class F1 bricks are normally durable in the outer face of a building as long as … .

7. Calcium silicate bricks are generally exposure is not severe and appropriate measures have been taken in the design of the wall to prevent saturation.

8. Most concrete blocks are equivalent in size to F0 .

Floors

Floors belong to one of the most important functional components of a building. They influence the acoustics of a room: it depends on whether a hard or soft flooring is used. Floors also react in various ways with light. Some flooring materials are known to produce mirrorlike reflection. Dark flooring materials, on the contrary, absorb light and this absorption makes a room darker. The light materials reflect light and help create a lighter and brighter room.

Floors are subject to moisture, dirt, and dust. They are also subject to the action of feet and the load of furniture. That’s why they require more cleaning and maintenance work than any other components of a building.

Basically, there are two kinds of floors for interiors: those that are an integral part of the structure and those that are applied after the structure is completed (floor finishes). The former are a careful selection of hard, dense material such as broken brick or stone which is chemically stable. They can be strengthened by compaction to form a firm foundation for the structure. The latter are designed at a later stage and are often changed in the course of a building's life. In areas of higher traffic harder surfaces may be used – for example, cut stone tiles of marble or granite. Floor finishes in commercial and institutional uses make considerable use of synthetic-fibre carpeting.

Synthetic floor coverings are usually classified as resilient floors. The resilient flooring materials include linoleum, cork, and vinyl. Basically, resilient floor tiles are excellent flooring materials that are both economical and easily maintained. The tiles can be plain or they can imitate stone, brick, mosaic, or other materials.

Ceramic and quarry tiles are made not only for such areas as bathrooms but are suitable for almost any space. Installation usually requires a cement bed over the existing subfloor, making this material difficult to use in existing buildings. Like other natural materials, quarry-tile floors possess a natural beauty and have the additional advantage of easy maintenance.

Ex. 13. Agree or disagree with the following statements.

Date: 2016-01-05; view: 966