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A suspended timber ground floor abuts a 300 mm concrete block external wall of a dwelling house - Leaving Cert Construction Studies - Question 4 - 2007
Question 4
A suspended timber ground floor abuts a 300 mm concrete block external wall of a dwelling house. (a) Using notes and freehand sketches show the construction details... show full transcript
Worked Solution & Example Answer:A suspended timber ground floor abuts a 300 mm concrete block external wall of a dwelling house - Leaving Cert Construction Studies - Question 4 - 2007
Step 1
Using notes and freehand sketches show the construction details of the wall and the suspended timber ground floor from foundation to finished floor level.
Answer
To construct a suspended timber ground floor abutting a 300 mm concrete block wall, follow these steps:
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Foundation Preparation: Start with a solid foundation, ensuring proper leveling. The footing should be poured to a minimum depth of 1 meter to support the wall structure.
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Concrete Block Wall: Construct a 300 mm external concrete block wall. Ensure that blocks are laid according to relevant construction codes, making sure to allow for insulation.
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Installation of Radon Barrier: Position a radon barrier (Damp Proof Membrane) on top of the foundation level. This layer serves as a protective barrier against radon gas penetration.
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Timber Floor Joists: Install timber floor joists on top of the radon barrier, spaced according to structural requirements (usually 400 mm to 600 mm apart). Joists should be treated timber, adhering to IS 444.
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Flooring and Insulation: Use plywood or chipboard for the flooring, supported by the joists. Include appropriate insulation (e.g., rigid insulation) between the joists to aid in thermal resistance. The top surface of the floor should be at least 10 mm higher than the highest part of the ground adjacent to the external wall.
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Ventilation: Ensure provision for air ventilation by incorporating voids or vents which allow air to travel underneath the floor, reducing moisture build-up.
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Finishing Touches: Finally, ensure that all connections and joints are secure, and cover with a finished floor material, such as laminate or tile, maintaining a moisture barrier.
Step 2
Discuss in detail two functional requirements of a suspended timber ground floor for a domestic dwelling.
Answer
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Resistance to Dampness: One of the critical requirements of a suspended timber ground floor is its ability to resist dampness. This is typically achieved by placing a continuous layer of impervious material (a Damp Proof Membrane or DPM) within the construction. This prevents moisture from rising through the floor from the ground below, minimizing the risk of decay in the timber.
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Thermal Insulation: A suspended timber ground floor should also provide adequate thermal insulation to maintain comfortable indoor temperatures. This is accomplished by incorporating insulating materials between the joists, which help to reduce heat loss. The use of rigid insulation boards or other insulating materials aids in providing a warm living space and promotes energy efficiency.