KCSE 2015 Building and Construction Paper 1 with Marking Scheme

SECTION A (40 marks)
Answer ALL the questions in this section in the spaces provided.

1.    
   1. State two requirements for safe storage of each of the following items: (2 marks)
      
      1. tools;
      2. materials.
   2. Explain the following terminologies as used in setting out: (2 marks)
      
      1. baseline;
      2. site datum.
2.    
   1. Distinguish between tamping and screeding as used in concreting. (2 marks)
   2. State one disadvantage of using each of the following materials for damp-proofing: (2 marks)
      1. polythene paper;
      2. bituminous felt.
3.    
   1. Draw a pictorial sketch of a stepped foundation. (3 marks)
   2. Sketch and label a vertical cross section through a reinforced strip foundation. (4 marks)
4.    
   1. State the type of climate where each of the types of buildings in Figure 1 is used. (2 marks)
      
   2. Sketch and label a cross section of a hogsback coping stone. (2 marks)
5. Sketch and label a flat arch. (4 marks)
6.      
   1. State one function of each of the following fixings: (2 marks)
      
      1. architrave;
      2. skirting,
   2. State the recommended pipe size for supplying water to the following sanitary fittings: (2 marks)
      
      1. wash hand basin; ...........
      2. bath tub. ........
7. State two functional requirements of each of the following:
   
   1. doors; (2 marks)
   2. walls. (2 marks)
8. Differentiate between pointing and jointing as used in wall finishes. (2 marks)
9.    
   1. State the function of each of the following parts of a scaffold: (2 marks)
      
      1. base plate;
      2. guard rail.
   2. State two activities that a contractor must carry out at the end of a construction project. (2 marks)
10. Figure 2 shows orthographic views of a block drawn in 1s angle projection.
    
    To a scale of 1:1, draw the block in oblique projection with F as the face nearest to the viewer.(3 marks)

SECTION B (60 marks)
Answer question 11 on the A3 paper provided and any other THREE questions from this section in the spaces provided. Candidates are advised NOT to spend more than 25 minutes on question 11.

11. Figure 3 shows a pictorial view of a machine bracket.
    
    To a scale of 1:1, draw the following orthographic views in third angle projection:
    1. Front elevation in the direction of arrow F. E;
    2. End elevation in the direction of arrow E. E;
    3. Plan. (15 marks)
12.    
    1. Outline the procedure of laying a cement/sand floor screed on an old floor slab. (6 marks)
    2. Use a labelled sketch to show how hot water is supplied from a hot water cylinder to a bath tub. (4 marks)
    3. With the aid of a labelled sketch, explain the use of a marginal draft in stone dressing. (5 marks)
13.    
    1. State two advantages of each of the following classes of paints: (4 marks)
       1. oil-based paints;
       2. water-based paints.
    2. Using pictorial sketches, distinguish between header bond and stretcher bond in brickwork. (6 marks)
    3. Sketch and label a vertical cross section to show timbering in loose soils. (5 marks)
14.    
    1. State four reasons for choosing stones as a building material over other materials. (4 marks)
    2. State three functions of the following finishes in buildings: (6 marks)
       1. plaster;
       2. floor screed.
    3. Sketch and label a roof detail at the ridge for a roof covered with galvanized corrugated iron (GCI) sheets. (5 marks)
15.    
    1. Sketch and label a vertical section through a manhole. (9 marks)
    2. Sketch the following carpentry joints:
       1. corner mortice and tenon joint;(3 marks)
       2. half lap dovetail tee joint. (3 marks) 

MARKING SCHEME

1.    
   1. Safety requirements in:
      1. Storage of tools:
         • Tools should be cleaned and oiled
         • Small tools should be kept in lockable cabinets
         • Tools hanging in open shelves should either be silhouetted or numbered
         • Doors to tools store should be lockable Keep inventory of tools
      2. Storage of materials:
         • Materials to be stacked in an orderly manner.
         • Materials like metal pipes to be kept off the ground in stacks.
         • Galvanized iron bars and pipes to be kept in weather proofed stores or sheds
           Any (2 x 2 x 1/2) = 2 mark
   2.    
      1. Baseline:
         This is a grid line set on site from which all the other lines will be established when setting out.
      2. Site datum:
         This is a fixed point on site from which all measurements are taken.
         2 x 1 = 2 marks
2.    
   1. Tamping is done using a tamping rod to eliminate air pockets in the concrete. It is also referred to as compaction. Screeding is an operation done by use of a straight edge on freshly laid concrete to achieve the proper grading and slope on the concrete surface.
      (1 x 2 = 2 marks)
   2. Disadvantage of using the following materials as dpc
      1. Polythene paper
         • It is easily punctured
         • it tears easily
           Any 1 x 1 = 1 mark
      2. Bituminous felt
         • it is expensive
         • It is not easily available
           Any 1 x 1 = 1 mark
3.    
   1.   
      
   2. REINFORCED STRIP FOUNDATION
      
4.    
   1.    
      1. Hot climate
      2. Cold climate (2 marks)
   2.   
      
5.   
   
6.    
   1. Functions of
      1. Architrave:
         • (Seals) hide joint between frame and wall
         • Provide a beautiful finish
      2. Skirting:
         • (seals) hide joint between wall and floor
         • provide a beautiful finish
         • prevent water splashing on lower wall when washing the floor.
           (1 x 2 x 1 = 2 marks)
   2. Recommended pipe sizes for
      1. wash hand basin = Φ 12 mm (1 mark)
      2. bath tub = Φ 20 mm (1 mark)
7. Functional requirements of
   1. Doors
      • Properly hung to open and close with ease
      • Sufficient fire resistance
      • Sufficient sound insulation
      • Strong
      • Weather resistance
        (Any 2 x 1 = 2 marks)
   2. Walls:
      • Strong and stable
      • Carry their own weight and loads from above
      • Adequate fire resistance
      • Adequate sound insulation.
      • Weather resistance
        (Any 2 x 1 = 2 marks)
8. Pointing is a finish on masonry joints done after the walling is complete while jointing is a finish on masonry joints done as the work proceeds. (2 x 1 = 2 marks)
9.    
   1. Functions of parts of a scaffold:
      1. Baseplates
         • It distributes the weight of standard
         • It supports the standard
         • It is for adjusting heights in adjustable baseplates
         • It is for swivelling on sloping ground
      2. Guard rail
         • It prevents the workers from falling off
         • It prevents materials from falling off.
           (Any 1 x 2 = 2 marks)
   2. Activities at the end of a construction project
      • handing over the site
      • making good the surrounding
      • removing machines used
      • demolishing the site huts
        (Any 2 x 1 = 2 marks)
10.   
    
11.   
    
12.    
    1. Procedure of laying a floor screed
       1. Hack the surface of the old floor slab
       2. Brush off the dust and sprinkle water
       3. Pour cement slurry on the floor surface
       4. Mix mortar to predetermined ratios
       5. Pour, spread, consolidate and level the screed
       6. Finish the surface to the desired finish
          (1 x 6 = 6 marks)
    2.   
       
    3. 
       
       Accept either of the sketches
       A marginal draft is a strip of approximately 20 - 40 mm that is dressed flat and square around a surface of a stone to give guidance as to the depth and dimensions when dressing a stone.
       Sketch - 2 marks
       Explanation - 3 marks 
       = 5 marks
13.    
    1. Advantages of:
       1. Oil - based paints
          • Easy to clean the surface
          • They are resistant to fading / don't fade
          • They are attractive
          • They are durable
            (Any 2 x 1 = 2 marks)
       2. Water - based paints
          • Ease clean up
          • Have stable colour over time
          • Dry quickly
          • They are odour free
            (Any 2 x 1 = 2 marks)
    2. 
       
       Headerbond consists of entire headers showing on the face of the wall while stretcher bond has an arrangement showing only stretchers on the face of the wall.
       Sketching - 2 x 2 = 4 marks
       Explanation -  2 x 1 = 2 marks
       = 6 marks
    3. 
       
       Correct sketch = 2 marks
       Any 3 correct labels= 3 marks
       = 5 marks
14.    
    1. Advantages of stones
       • Readily available
       • Available in different colours and textures
       • Can be dressed to the desired shape and size
       • They are durable
       • They have good thermal and sound insulation properties
         (Any 4 x 1 = 4 marks)
    2. Functions of the following:
       1. Plaster
          • Is a background for other finishes that are more durable like paint etc
          • Provides an attractive surface / aesthetics
          • Provides a weather and water resistant surface
          • Provides a surface that is resistant to chemical attack
            (Any 3 x 1 = 3 marks)
       2. Floor screed
          • Provide a hard surface finish
          • Provides a surface for other finishes like tiles etc
          • Provides adequate thermal insulation
          • Provides adequate acoustics (beauty).
            (Any 3 x 1 = 3 marks)
    3.   
       
15.    
    1.  
        
    2.    
       1. Corner Mortise and Tenon
          
       2. Half lap dovetail tee joint
          
          Sketch = 3 marks