Underline or mark the main ideas of Text 12A and retell it in English.
19. Skim Text 12B "Drywall" and try to understand what it is about and what information is already known to you.
• TEXT 12B
Drywall is the term used for a common method of constructing interior walls and ceilings using panels made of gypsum plaster pressed between two thick sheets of paper, then kiln dried. Many such panels are made with fiberglass instead of paper to prevent mold growth, which is common with paper that has been exposed to water due to plumbing leaks or floods. Drywall construction is used globally for the finish construction of interior walls and ceilings. Drywall construction became prevalent as a speedier alternative to using plaster-based interior finish techniques, which involved forcefully spreading a substrate of coarse plaster, known as the base made up of the scratch coat and brown coat, onto the wall lath-work before finally applying the smoother finish coat, each layer added in succession and all by hand. Drywall, by contrast to plaster, requires hand finishing only at the fasteners and joints. The drywall process requires less labour and drying time, lending its name to the panels used in the assembly.
As opposed to a week-long plaster application, an entire house can be drywalled in one or two days by two experienced drywallers, and drywall is easy enough to use that it can be installed by many amateur home carpenters. In large-scale commercial construction, the work of installing and finishing drywall is often split between the drywall mechanics, or hangers who install the wallboard and the
tapers and mudmen, or float crew who finish the joints and cover the nailheads with drywall compound.
Drywall is cut to size using a large
T-square by scoring the paper on the front
side (usually white) with a utility knife
breaking the sheet along the cut, scoring
Example of drywall the paper backing, and finally breaking
hung vertically with the sheet in the opposite direction. Small
joint compound features such as holes for outlets and light
switches are usually cut using a keyhole
saw or a small high-speed bit in a rotary tool. Drywall is then
fixed to the wall structure with nails, glue or drywall screws. Drywall
fasteners are gaining popularity in both residential and commercial
construction. Drywall fasteners are used for supporting interior
drywall corners and replacing the non-structural, wood or metal
blocking that traditionally was used to install drywall. Their function
serves to save on material and labour expenses, to increase energy
efficiency, and to make plumbing installation simpler.
After the sheets are secured to the wall studs or ceiling joists,
the seams between drywall sheets are concealed using joint tape,
and several layers of the compound sometimes called mud. This
compound is also applied to any screw holes or defects.
Alternatively, for a better finish the entire wall may be given a
skim coat, a thin layer of finishing compound, to minimise the
visual differences between the paper and mudded areas after painting.
Another similar skim coating is always done in a process called
veneer plastering, although it is done slightly thicker. Veneering
uses a slightly different specialised setting compound (finish plaster)
that contains gypsum and lime putty. This application uses blueboard
which has special treated paper to accelerate the setting of the gypsum
plaster component. This setting has less shrinkage than the air-dry
compounds used in drywall, so it only requires one coat. Blueboard
has square edges rather than the tapered-edge drywall boards. The
tapered drywall boards are used to countersink the tape in taped
272 Английский язык для студентов строительных специальностей
UNIT 12. FINISHING THE INSIDE
5) Finish plaster contains
c) gypsum and lime putty.
22. Read Text 12C "Plasterwork" and find the answers to these questions. Discuss them with your groupmates.
a) What does plasterwork refer to?
b) What is the process of creating plasterwork called?
c) Why is plasterwork regarded as one of the most ancient of building techniques?
d) What were a plasterer's tools in Egypt?
e) Where was plaster of a fine white lime stucco used?
f) What are the changes in modern plasterers' tools?
g) What are specific features of drywall and plaster?
h) What are the differences between veneer plastering and the drywall method?
• TEXT 12C
Plasterwork refers to construction or ornamentation done with plaster, such as a layer of plaster on an interior wall or plaster decorative moldings on ceilings or walls. This is also sometimes called pargeting. The process of creating plasterwork called plastering has been used in building construction for centuries.
Plasterwork is one of the most ancient of building techniques. Evidence shows that the dwellings of primitive man were erected in a simple fashion with sticks and plastered with mud. The pyramids in Egypt contain plasterwork executed at least four thousand years ago, probably much earlier, and yet hard and durable at the present time. From recent discoveries it has been ascertained that the tools of the plasterer of that time were practically identical in design, shape and purpose with those used today. For their finest work the
Egyptians used a plaster made from calcined gypsum just like plaster of Paris of the present time, and their methods of plastering on reeds resemble in every way our lath, plaster, float and set work. Hair was introduced to strengthen the material.
Very early in the history of Greek architecture plaster of a fine white lime stucco was used, such has been found at Mycenae. The art had reached perfection in Greece more
than five centuries before Christ, and plaster was frequently used to cover temples externally and internally, in some cases even where the building was of marble. It formed a splendid ground for decorative painting.
Tools and materials include trowels, floats, hammers, screeds, scratching tools, utility knives, laths, lath nails, lime, sand, hair, plaster of Paris, a variety of cements, and various ingredients to form colour washes. While most tools have remained unchanged over the centuries, developments in modern materials have led to some changes. Trowels constructed from steel are available in a polycarbonate material that allows the application of certain new acrylic-based materials without staining the finish. Floats traditionally made of timber are often finished with a layer of sponge or expanded polystyrene.
There are two main methods used in construction of the interior walls of modern homes, drywall and plaster. In drywall a specialized form of sheet rock known as greenboard (yclept because on the outer paper coating is greenish) is screwed onto the wall-frames (studs) of the home to form the interior walls. At the place where the two edges of wallboards meet there is a seam. These seams are covered with mesh tape and then the seams and the screw heads are concealed with the drywall compound to make the wall seem as one uniform
274 Английский язык для студентов строительных специальностей
UNIT 12.FINISHING THE INSIDE 275
piece. Later this is painted or wallpapered over to hide the work. This pro-cess is called taping and those who use drywall are known as tapers.
Veneer plastering differs from the drywall method in a number of ways. The two most notable differences are that a thin plaster coat covers the entire wall and not just the seams, and secondly the drywall compound is a thick paste where plaster method uses a great deal of water and is applied very wet. Another difference is that walls intended to be plastered are hanged with blueboard (named as such for the industry standard of the outer paper being blue-grey in colour). This type of sheet rock is designed to absorb some of the moisture of the plaster and allows it to cling better before it sets. Plastering is also a one-shot one-coat application; taping usually requires sanding and then adding an additional coat since the compound shrinks as it dries. From a supply side the cost of plaster and drywall are approximately the same, but the labour cost of plastering is usually much greater.
SECTION 4 LISTENING AND SPEAKING
23. Listen to the Text "Interior Finishes of Residential Buildings".
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