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The sketch shows a portion of a closed-string wooden stairs in a dwelling house - Leaving Cert Construction Studies - Question 5 - 2022
Question 5
The sketch shows a portion of a closed-string wooden stairs in a dwelling house. The rise of each step is 170 mm. (a) To a scale of 1.5, draw a vertical section thr... show full transcript
Worked Solution & Example Answer:The sketch shows a portion of a closed-string wooden stairs in a dwelling house - Leaving Cert Construction Studies - Question 5 - 2022
Step 1
To a scale of 1.5, draw a vertical section through the centre of the bottom three steps of the stairs.
Answer
To begin, set the scale to 1:5 on your drawing board. Draw a vertical section of the three steps, maintaining the dimensions provided:
- String: 250 mm wide and 50 mm thick.
- Treads: 250 mm deep and 25 mm thick.
- Risers: 170 mm high and 20 mm thick.
In your drawing:
- Clearly indicate the string, treads, and risers using appropriate line weights.
- Mark three typical dimensions using dimension lines, ensuring the measurements are legible.
- Include a joint between the tread and riser, noting that the minimum nosing projection should be 16 mm.
- Add a horizontal wedge for stability, with glue blocks of size 60 mm x 60 mm positioned on the string.
- Ensure the pitch line does not exceed 42 degrees.
Step 2
On your drawing, show one design detail to prevent creaking when the stairs is in use.
Answer
To illustrate a design detail that prevents creaking, incorporate a block joint in the drawing. This can be shown as follows:
- Use of horizontal and vertical wedges: This detail helps to tightly secure the connection between the riser and tread, minimizing movement.
- Label these joints and their positions clearly to emphasize their function.
- Optionally, you can depict another suitable detail in compliance with Building Regulations if space permits, ensuring clarity in the drawing.