NATIONAL CERTIFICATE (VOCATIONAL) CARPENTRY AND ROOF WORK NQF LEVEL 2 SUPPLEMENTARY 2010

Transcription

1 NTIONL ERTIFITE (VOTIONL) RPENTRY N ROOF WORK NQF LEVEL 2 SUPPLEMENTRY 2010 ( ) 18 March (X-Paper) 09:00 12:00 alculators may be used. This question paper consists of 7 pages, 1 table sheet and a 1-page diagram sheet.

2 ( ) -2- N300(E)(M18)V TIME: 3 HOURS MRKS: 100 INSTRUTIONS N INFORMTION nswer LL the questions. Follow LL the instructions given in the question paper. Read LL the questions carefully. Keep the subsections of questions together. Sketches should be neat, clear and done in PENIL. RULE OFF across the page on completion of each subsection. Start each question on a NEW page. LL work you do NOT want to be marked must be clearly crossed out. Number the answers according to the numbering system used in this question paper. Write neatly and legibly.

3 ( ) -3- N300(E)(M18)V QUESTION 1: GENERL 1.1 State THREE requirements with which the roof of a building must comply, as per National uilding Regulations: Part L. (3) 1.2 What are the 'deemed to satisfy rules' in the National uilding Regulations based on? (2) 1.3 Refer to the TLE SHEET, TLES 1 and 2: SNS The are specific national standards that apply to the construction of roofs. Study the descriptions below and write only the required specification next to the question number ( ) in the NSWER OOK The maximum truss centres for concrete tiles using 38 mm x 38 mm battens (1) The maximum purlin centres for metal ribbed sheets using 50 mm x 76 mm on edge (1) The maximum truss centres for fibre-cement slates using 38mm x 38 mm battens (1) The maximum batten centres for concrete tiles using 38 mm x 50 mm battens on flat (1) The maximum truss centres for metal ribbed sheets using 38 mm x 76 mm on edge (1) The wall plate size for a metre span (1) The maximum truss centres for profiled metal tiles using 38 mm x 38 mm battens (1) The maximum truss spacing for natural slate using 38 mm x 38 mm battens (1) The maximum truss centres for concrete tiles using 38 mm x 50 mm on flat (1) The maximum truss centres for fibre-cement sheets using 50 mm x 76 mm on edge (10 x 1) (1) (10) [15]

4 ( ) -4- N300(E)(M18)V QUESTION 2: TERMINOLOGY IN ROOF WORK 2.1 State TWO characteristics of a competent person in this context. (2) 2.2 escribe the characteristics of a timber roof truss. (3) 2.3 ompare nail plate trusses with prefabricated trusses by listing ONE advantage and ONE disadvantage of each method. (4) 2.4 Give THREE reasons for using rational design. (3) 2.5 What is the difference between verges and eaves? (2) 2.6 Using simple line drawings, sketch and label FIVE different types of trusses. (5) 2.7 Make a neat sectional sketch of a Howe roof truss and indicate the following: The wall The wall plate Top chords ottom chords King post randering Purlins/battens (7) [26] QUESTION 3: ROOF ONSTRUTION 3.1 nswer the following questions: Why does a building have a roof? (1) What is the purpose of a wall plate? (2) Name TWO types of live loads. (2) 3.2 efine the following terms: pex Run Truss span Rise Pitch (5 x 1) (5)

5 ( ) -5- N300(E)(M18)V 3.3 omplete the following paragraph by filling in the missing words. hoose the answer and write only the word(s) next to the question number ( ) in the NSWER OOK. hoose the words from the box given below. nails; right angles; shear; flush; washers The National Home uilder s Registration ouncil requires that (3.3.1) should be driven at (3.3.2), to the face of the timber, in order to prevent (3.3.3) and to a depth so that the heads of the nails are (3.3.4) with the timber surface. Nuts should be tightened so that the (3.3.5) bites into the surface of the timber. (5 x 1) (5) 3.4 State the sizes of TWO types of battens used for concrete tiled roofs. (2) 3.5 Why is a tilting batten used on a concrete tiled roof? (1) 3.6 What is the purpose of temporary bracing? (1) 3.7 Indicate whether the following statements are TRUE or FLSE. hoose the answer and write only true or false next to the question number ( ) in the NSWER OOK The chords of a truss are effectively supported laterally (side to side) by battens and purlins If ceiling brandering is installed in roofs clad with metal sheeting, then tie beam bracing should be installed Purlins, battens and brandering do not assist in the bracing of a roof Gable walls should be used to stabilise the roof structure Top chords are in tension Gable-to-gable roofs are more stable than hipped roofs. (6x1) (6) [25]

6 ( ) -6- N300(E)(M18)V QUESTION 4: GLE ROOF ONSTRUTION 4.1 Various options are given as possible answers to the following questions. hoose the answer and write only the letter ( ) next to the question number ( ) in the NSWER OOK Nails and bolts should NOT be located closer than, from the edge of the timber. 20 mm 25 mm 30 mm 32 mm (1) The skew nail should NOT be closer than from the edge of the timber. 20 mm 25 mm 30 mm 32 mm (1) Top chord bracing on gable-to-gable roofs with battened roofs, with spans of more than 6,6 metres... are fixed to the gable wall. are fixed to the apex. are fixed to the wall plate. are fixed to the heel shelf. (1) On a concrete tiled roof of up to an 8,5 metre span, the top chord bracing is fixed in the middle of the top chord. on the bottom side of the top chord. on the top side of the top chord. on the end of the chord. (1) The National Home uilder's Registration ouncil stipulates that LL bolts should have a head? coach slotted machine hexagonal (1)

7 ( ) -7- N300(E)(M18)V 4.2 omplete the following paragraph by filling in the missing words. Write only the word(s) next to the question number ( ) in the NSWER OOK. hoose from the list in the box below. steel straps; heel; tied; steel wires; supporting Trusses shall only be supported at the (4.2.1) joints and not on (4.2.2) walls. ll trusses shall be (4.2.3) down to the supporting walls by means of galvanised (4.2.4) or (4.2.5) (5 x 1) (5) 4.3 escribe TWO ways of manually handling roof trusses. (2) 4.4 carpenter is required to do the setting out of a roof truss for a gable-to-gable building covered with natural slate. SPEIFITIONS: The roof pitch is 30º. The clear span is 8 metres. The wall plate size is 114 mm X 38 mm. alculate the height of the kingpost using simple trigonometry. Use the formula: tan Θ = O/. (5) HINT: raw a sketch to help you in your calculations. 4.5 The IGRM SHEET shows sketches of roof bracing. Label the parts as indicated in the sketches. Write only the correct name and/or part name next to the question numbers ( ) in the NSWER OOK. (10) 4.6 Roof trusses for a gable-to-gable roof should be level. Explain how a truss is levelled. (3) 4.7 Explain why roof anchors should be pulled taut? (1) 4.8 What is used to ensure that the apexes of roof trusses are in line? (1) 4.9 How can one ensure that the rafters and tie beams are straight? (1) 4.10 How is the plumbness of a truss ensured? (1) [34] TOTL: 100

8 ( ) -8- N300(E)(M18)V TLE SHEET TLE 1 SNS TLE 2 SNS 10243

9 ( ) -9- N300(E)(M18)V IGRM SHEET