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Thermal envelope continuity is essential to ensure a dwelling house is thermal bridge free - Leaving Cert Construction Studies - Question 9 - 2019
Question 9
Thermal envelope continuity is essential to ensure a dwelling house is thermal bridge free. The drawing shows an outline section through the external door of a singl... show full transcript
Worked Solution & Example Answer:Thermal envelope continuity is essential to ensure a dwelling house is thermal bridge free - Leaving Cert Construction Studies - Question 9 - 2019
Step 1
Using notes and freehand sketches, show best practice design detailing that will prevent the formation of a thermal bridge at each location circled on the drawing.
Answer
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Location 1 (External Door Frame):
To avoid thermal bridging, ensure that the door frame is designed with a thermal break. This can be achieved by using insulated materials around the frame to reduce heat transfer. Incorporate a flexible sealant at the junction between the door frame and the wall to eliminate any gaps that may lead to cold spots. -
Location 2 (Cavity Wall Junction):
Implement a continuous layer of insulation extending from the walls into the door frame area. The external wall should be insulated with full-fill insulation batts to maintain a thermal barrier along the entire perimeter of the door opening. -
Location 3 (Roof Junction):
When connecting the traditional cut roof to the external wall, employ a thermal break in the roof trusses or rafters. Insulation should be placed in contact with the roof structure and carried down into the wall section to mitigate cold bridging. -
Location 4 (Ground Floor Junction):
Introduce a continuous insulated layer in the ground floor that meets the wall insulation, ensuring that there are no thermal gaps. The insulation should wrap around the edge of the ground floor to form a thermal envelope around the dwelling.
Step 2
Discuss two negative impacts of thermal bridging as a result of poor design detailing.
Answer
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Mould Growth and Health Risks:
Thermal bridging can result in cold spots in the internal environment, leading to condensation. This moisture creates a perfect environment for mould growth, which can be inhaled and cause respiratory health issues in occupants. -
Energy Inefficiency:
Areas of thermal bridging can lead to increased energy consumption as the heating system works harder to maintain comfortable temperatures in the dwelling. This not only raises utility costs but also contributes to a higher carbon footprint, making the building less environmentally sustainable.