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A four panel solid wooden door and doorframe are fixed in the external wall of a dwelling house, as shown in the accompanying sketch - Leaving Cert Construction Studies - Question 4 - 2008
Question 4
A four panel solid wooden door and doorframe are fixed in the external wall of a dwelling house, as shown in the accompanying sketch. The doorframe is 120 mm x 75 m... show full transcript
Worked Solution & Example Answer:A four panel solid wooden door and doorframe are fixed in the external wall of a dwelling house, as shown in the accompanying sketch - Leaving Cert Construction Studies - Question 4 - 2008
Step 1
Draw a vertical section through the external wall, doorframe and door.
Answer
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Begin by sketching the external wall, ensuring to note its thickness as 300 mm. Include the following:
- A 19 mm external render on the outer face.
- The outer concrete block leaf, which is 100 mm thick.
- Indicate a residual cavity of 40 mm to accommodate insulation.
- Draw the concrete block inner leaf, ensuring it is 100 mm thick as well.
- These details should be clearly depicted in the vertical section.
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Illustrate the doorframe:
- The frame width should be 120 mm and the height referenced from the provided dimensions.
- Draw the door with a width of 120 mm and a height of 75 mm, with details for the top rail showing its dimensions (120 mm x 50 mm).
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Indicate the pre-stressed concrete lintel above the door, along with the necessary steel reinforcement to comply with building regulations.
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Ensure the insulation details comply with current building regulations, particularly around the cold bridge effect.
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Add internal plaster, denoting the thickness of 15 mm on the inner face of the concrete block leaf, where applicable.
Step 2
Include on your drawing a design detail to ensure that moisture does not penetrate to the inner leaf of the wall at the door head.
Answer
Add a design detail to your drawing to prevent moisture ingress:
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Include a stepped Damp Proof Course (DPC) at the door head, ensuring that it is installed between the inner and outer leaf of the wall.
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Clearly label the DPC in your drawing, detailing its position relative to both leaves.
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Ensure that the DPC slopes away from the door frame, which helps to direct moisture away from the wall structure.
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Use terms such as "Stepped DPC" to highlight the purpose of this feature, following good building practices.