 |  | Carpentry for Vocational Schools - A Teacher's handbook (GTZ, 252 p.) | ||
 |  | 15. OUTSIDE CLADDING | ||
|  | (introduction...) | ||
| | 15.1. Timber weather boards | ||
| | 15.2. Fibre cement boards | ||
| | 15.3. ''V'' crimp iron | ||
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TOPIC: 15. OUTSIDE CLADDING
INTRODUCTION: This topic teaches students the different types of weather boards and other materials walls can be covered with.
OBJECTIVES:
15.1. Students should be able to state use and characteristics of weather boards. They also should know how weather boards are nailed and joined correctly.
15.2. Students should be able to describe what fibre cement boards are and how they are joined and nailed to the wall.
15.3. Students should be able to define what "V" crimp iron is and how it is joined and nailed to the walls.
METHOD: Prepare samples of different types of weather boards, fibre cement boards and joints, and V - crimp iron and display it in the classroom.
Explain the advantages and disadvantages of each type of wall cladding in the classroom and if there are houses with different types of cladding near the school they can be inspected for better understanding.
NOTE: At the end of this topic prepare again a worksheet for the students to complete as their homework. Worksheets are collected later, corrected and assessed.
There are several types of material used for cladding the exterior walls of timber framed buildings. The most common types in P.N.G. are timber weatherboards, fibrecement boards or "V" crimp metal sheets. The main purpose of the outside cladding is to protect the timber framed buildings from rain and wind.
Solid timber, in the form of weatherboards, is a widely used type of cladding in P.N.G. Usually the boards are moulded to overlap and look attractive. Normally soft textured timbers are used to reduce the wear on cutters during the moulding process. The use of naturally resistant or pressure treated timber is essential.
a) There are different profiles of weatherboards:
Figure
b) Fixing the boards:
When fixing the boards to the frame only one nail is used in each stud for each board. The nail must be placed near the lower edge of the board as the top edge will be held in place by the next board. Only galvanized 50 mm jolthead nails are used as they do not rust. Each nail has to be punched immediately, taking care not to leave a hammer head impression on the boards.
Figure
c) Joining weatherboards at external and internal corners:
- External corner
Figure
- Internal corner
Figure
The fibre cement boards are manufactured in a standard thickness of 4.5 mm and have different heights and widths. The studs should be spaced according to the width of the sheets. Where special size sheets are required, as over doors or under windows, sheets may be cut with a fibre cement cutter.
a) Nailing: - The sheets should be nailed along all edges to studs or noggings approximately 400 mm apart and 10 mm from the edges with clouthead nails. Where joints occur on a stud, plastic joints must be used .
Figure
These boards are made from 0.8 mm metal sheet and are crimped "v" shape to strengthen the sheet. It is possible to buy it in different lengths. Only vertical nailing is possible with these boards. For nailing, only clouthead nails are used and are nailed at every corrugation.
Figure
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