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The sketch shows a dwelling house which was built over ten years ago - Leaving Cert Construction Studies - Question 2 - 2013
Question 2
The sketch shows a dwelling house which was built over ten years ago. The external walls of the house are 300 mm concrete block walls with an un-insulated cavity. It... show full transcript
Worked Solution & Example Answer:The sketch shows a dwelling house which was built over ten years ago - Leaving Cert Construction Studies - Question 2 - 2013
Step 1
Insulating the cavity
Answer
To insulate the cavity of the external walls of the house, the following steps should be taken:
- Drilling: Holes of 22 mm diameter are drilled through the external leaf of the wall, either at the window headers or the top of the wall.
- Spacing: The holes are spaced at 800 mm horizontally and 1350 mm vertically.
- Extra Holes: Additional holes are drilled beneath window sills and above door headers to ensure proper filling of the cavity.
- Insulation Injection: The insulation material, typically polystyrene beads, is pumped into the cavity by a specialist company.
- Sealing: After the insulation is pumped in, a light coating of glue is applied to the beads.
- Finishing: The holes are then filled and painted to blend with the existing wall finish.
The insulation material used is usually polystyrene beads.
Step 2
Adding a system of insulation to the inside of the walls
Answer
To add insulation to the inside of the walls, follow these steps:
- Batters Installation: Fix 50 mm x 50 mm battens to the inside surface of the cavity wall, spaced 400 mm apart.
- Insulation Placement: Place insulation material, such as fibreglass or foam, between the battens. A vapor barrier should be included in this system.
- Plasterboard Application: Fit plasterboard of 12 mm thickness to the battens, which may also form part of the plaster slab.
- Skim Coat: Apply a skim coat of plaster over the plasterboard for a smooth finish.
In this approach, materials such as fibreglass, polyurethane, or cork can be used for insulation, enhancing thermal performance.
Step 3
List two advantages of improving the insulation properties of the external walls of the house
Answer
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Reduces Heat Loss: Improved insulation in the walls significantly reduces heat loss, keeping the interior warmer in the winter, which enhances comfort and reduces heating costs.
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Enhances Energy Efficiency: Better insulation improves the building's overall energy efficiency, reducing energy consumption and lowering utility bills, thus benefiting the environment.