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The sketch shows portion of the roof and external wall of a single-storey dwelling house - Leaving Cert Construction Studies - Question 1 - 2014
Question 1
The sketch shows portion of the roof and external wall of a single-storey dwelling house. The house has an internal span of 6.0 metres. The external wall is of timbe... show full transcript
Worked Solution & Example Answer:The sketch shows portion of the roof and external wall of a single-storey dwelling house - Leaving Cert Construction Studies - Question 1 - 2014
Step 1
To a scale of 1:10, draw a vertical section through one external wall and one rafter length.
Answer
To construct the vertical section:
- Draw the External Wall:
- Represent the outer leaf as a rendered concrete block (200 mm) and the inner leaf as a timber frame (200 mm).
- Indicate insulation within a 60 mm service cavity.
- Show the Roof Structure:
- Draw the prefabricated trussed rafters, making sure they are pitched at 30 degrees.
- Include the slate coverings and show three courses of slate at the eaves.
- Include Key Dimensions:
- Dimensions should be appropriately marked on the drawing adhering to the 1:10 scale.
- Detail from 400 mm below the ceiling joists up to the ridge level.
- Indicate Ventilation Paths:
- Draw openings for ventilation leading to the roof space, ensuring they are adequately sized to promote airflow.
- Final Touches:
- Label all components clearly and ensure the overall section is neat and proportionate.
Step 2
Indicate clearly the design detailing to ensure airtightness at the junction of the ceiling and the external wall.
Answer
To ensure airtightness at the junction:
-
Use of Vapour Barrier:
- Install a vapour barrier at the ceiling level that overlaps the wall insulation, preventing moisture ingress.
-
Seal Junctions:
- Use continuous sealing tape or mastic to seal all joints between the ceiling and the wall, ensuring a tight connection.
-
Insulation Continuity:
- Ensure insulation extends continuously from the ceiling into the wall cavity, avoiding gaps that could compromise airtightness.
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Attention to Detail:
- Incorporate details such as skimming finishes and plasterboard sealing at this junction to enhance the airtightness of the overall structure.