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A front porch with a flat roof projects 1.5 metres from the external wall of a house, as shown - Leaving Cert Construction Studies - Question 1 - 2016
Question 1
A front porch with a flat roof projects 1.5 metres from the external wall of a house, as shown. The roof of the porch is insulated, and is covered with layers of bit... show full transcript
Worked Solution & Example Answer:A front porch with a flat roof projects 1.5 metres from the external wall of a house, as shown - Leaving Cert Construction Studies - Question 1 - 2016
Step 1
To a scale of 1:5, draw a vertical section through the porch, showing the external wall, the flat roof and the window of the porch.
Answer
Begin your drawing by establishing the scale of 1:5. Start with the external wall of the house with the porch projecting 1.5 meters outwards. Clearly indicate the flat roof above the porch that uses layers of bituminous felt and plywood decking supported by 200 mm × 40 mm roof joists. Include the window frame within the section, which is triple-glazed and thermally broken. Make sure to represent the cavity wall construction behind the porch with 400 mm concrete block and the insulated plasterboard below the roof joists.
Add the following dimensions:
- Height from the base of the window frame to the top of the flat roof.
- Distance from the external wall to the front edge of the porch.
- Depth of the wall and porch construction.
- Measurement of the flat roof where it meets the external wall.
Each part of the drawing should be labeled appropriately for clarity.
Step 2
Show the typical construction details from a level 300 mm below the fixed frame of the porch window, through the walls, the window head, lintels, and flat roof to a level 400 mm above the abutment of the flat roof and the front wall of the house.
Answer
Detail the construction specifics starting from 300 mm below the window frame and continuing through to 400 mm above the flat roof abutment. Indicate lintels positioned to support the window head and detail how the frames integrate with the head and wall junction. Clearly include the vapor barriers and thermal insulation methods along with the air tightness measures, specifying materials such as galvanized steel wall brackets. Make sure to show how the flat roof is extended and how drainage is facilitated to avoid water pooling at the junctions.
Also, highlight the use of firestop materials and fixtures to ensure the seal is watertight at the meeting point of the flat roof and the main wall of the house.