planning:refurbishment_with_passive_house_components:the_enerphit_standard_applied_to_large_complex_existing_buildings
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planning:refurbishment_with_passive_house_components:the_enerphit_standard_applied_to_large_complex_existing_buildings [2016/06/06 11:56] – [The EnerPHit Standard applied to large, complex existing buildings] kdreimane | planning:refurbishment_with_passive_house_components:the_enerphit_standard_applied_to_large_complex_existing_buildings [2025/01/06 16:50] (current) – jgrovesmith | ||
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- | ====== The EnerPHit Standard applied to large, complex existing buildings ====== | + | ====== |
- | **Author: Steven Stenlund, BRE** | + | Author: Steven Stenlund, BRE |
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- | **Introduction** | + | |
- | \\ The Passive House Standard often cannot be feasibly achieved in existing buildings due to various difficulties as a direct consequence of the existing structure and orientation etc. Refurbishment to the EnerPHit Standard using Passive House components for all relevant structural elements in such buildings leads to extensive improvements with respect to thermal comfort, structural integrity, cost-effectiveness and energy requirements. | + | |
- | In terms of the UK EuroPHit case study building, Wilmcote House, it was decided that the first step would be to thermally upgrade the walls, windows and roof to a standard that will achieve a maximum specific heating demand of not more than 20 kWh/(m2.a) for a warm-temperate climate. | + | ===== Introduction ===== |
+ | The Passive House Standard often cannot be feasibly achieved in existing buildings due to various difficulties as a direct consequence of the existing structure and orientation etc. Refurbishment to the [[certification: | ||
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+ | In terms of the UK [[https:// | ||
Wilmcote House, built in the 1960s and owned by Portsmouth City Council, is a large residential building containing 100 three bedroom maisonettes above 7 ground floor one bedroom flats (and other ancillary accommodation) arranged in three towers linked with common stair cores. | Wilmcote House, built in the 1960s and owned by Portsmouth City Council, is a large residential building containing 100 three bedroom maisonettes above 7 ground floor one bedroom flats (and other ancillary accommodation) arranged in three towers linked with common stair cores. | ||
- | The decision to pursue a step-by-step approach to achieving the EnerPHit Standard allows for the provision of external wall and roof insulation and replacement glazing to be installed alongside the structural repairs, thus reducing overall costs. | + | The decision to pursue a **step-by-step approach to achieving the EnerPHit Standard** allows for the provision of external wall and roof insulation and replacement glazing to be installed alongside the structural repairs, thus reducing overall costs. |
The main feature of the external wall insulation is the enclosure of the external balcony approach to the upper floor dwellings. It was decided that to attempt to maintain the existing external balcony approaches to each property would lead to many difficult construction details that would cause many issues with regards to both achieving low levels of thermal bridging and a highly airtight building. In essence this has led to a designed ‘exoskeleton’ of steelwork being provided to encapsulate the entire building into which external wall insulation is provided in numerous layers to ensure that thermal bridging caused by the main steel structure is kept to a minimum level. | The main feature of the external wall insulation is the enclosure of the external balcony approach to the upper floor dwellings. It was decided that to attempt to maintain the existing external balcony approaches to each property would lead to many difficult construction details that would cause many issues with regards to both achieving low levels of thermal bridging and a highly airtight building. In essence this has led to a designed ‘exoskeleton’ of steelwork being provided to encapsulate the entire building into which external wall insulation is provided in numerous layers to ensure that thermal bridging caused by the main steel structure is kept to a minimum level. | ||
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The refurbishment works proceeded with the challenge of not being able to move residents out of the building during the construction works, due to the shortage of other 3 bedroom homes within the Council’s housing stock. | The refurbishment works proceeded with the challenge of not being able to move residents out of the building during the construction works, due to the shortage of other 3 bedroom homes within the Council’s housing stock. | ||
- | **Detailed design and implementation** | + | ===== Detailed design and implementation |
- | \\ Works commenced to Block A during 2015, and by September the steelwork exoskeleton had been erected to enclose the balcony approaches to each entry level to all properties. | + | Works commenced to Block A during 2015, and by September the steelwork exoskeleton had been erected to enclose the balcony approaches to each entry level to all properties. |
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The detailed drawing above provides an indication of how complex the existing structure is and how a new insulated façade was provided. In the section, the tie-back steel channels are shown as dashed lines. As the the main steelwork is positioned within the insulation build-up, it was also necessary to provide insulation to the underside of the existing concrete walkway even though the walkway would become enclosed within the thermal envelope as the steel tie-back channels would act as a significant thermal bridge. | The detailed drawing above provides an indication of how complex the existing structure is and how a new insulated façade was provided. In the section, the tie-back steel channels are shown as dashed lines. As the the main steelwork is positioned within the insulation build-up, it was also necessary to provide insulation to the underside of the existing concrete walkway even though the walkway would become enclosed within the thermal envelope as the steel tie-back channels would act as a significant thermal bridge. | ||
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The additional benefit of providing the steel exoskeleton is that the living accommodation on the upper floors (between entry levels), where extended outwards up to the new external wall line, provides for an enlarged lounge and a sun-room. This additional private space can be utilised for clothes drying or other uses in-lieu of the now removed balconies. | The additional benefit of providing the steel exoskeleton is that the living accommodation on the upper floors (between entry levels), where extended outwards up to the new external wall line, provides for an enlarged lounge and a sun-room. This additional private space can be utilised for clothes drying or other uses in-lieu of the now removed balconies. | ||
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Although the provision of the new external wall brought many benefits to the overall design of the building, there have been secondary consequences that have had to be addressed. Before the external wall was built, the kitchen windows opened directly onto the access walkways. However, with the introduction of enclosed walkways the kitchen windows had to be replaced with fixed fire rated window units allowing for a protected means of escape in event of a fire. It was also necessary to provide ‘purge’ ventilation to the kitchens using intermittent extract fans (in addition to the MVHR ventilation) with ducting through to the external to purge pollutants. This did pose a challenge to achieving the airtightness requirements of the building but a solution was found through fitting an in-line damper within the extract ductwork so when the intermittent fans were not in use, the ductwork would be sealed and airtight. | Although the provision of the new external wall brought many benefits to the overall design of the building, there have been secondary consequences that have had to be addressed. Before the external wall was built, the kitchen windows opened directly onto the access walkways. However, with the introduction of enclosed walkways the kitchen windows had to be replaced with fixed fire rated window units allowing for a protected means of escape in event of a fire. It was also necessary to provide ‘purge’ ventilation to the kitchens using intermittent extract fans (in addition to the MVHR ventilation) with ducting through to the external to purge pollutants. This did pose a challenge to achieving the airtightness requirements of the building but a solution was found through fitting an in-line damper within the extract ductwork so when the intermittent fans were not in use, the ductwork would be sealed and airtight. | ||
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- | **Concluding remarks** | + | |
- | \\ As of the time of writing (March 2016), Block A is nearing completion of the external works, while a significant number of dwellings have remained in occupation, for the most part throughout. Below is a render image of what Block A (left) and Block B (right) will look like upon completion, expected to be later this year (with the completion of Block C in 2017). | + | ===== Concluding remarks |
+ | As of the time of writing (March 2016), Block A is nearing completion of the external works, while a significant number of dwellings have remained in occupation, for the most part throughout. Below is a render image of what Block A (left) and Block B (right) will look like upon completion, expected to be later this year (with the completion of Block C in 2017). | ||
In terms of the EuroPHit project, the step-by-step approach, and ensuring that the fabric is upgraded first, the modelling of the proposals in PHPP v9 shows that each block meets the EnerPHit Standard in terms of specific heating demand as follows. | In terms of the EuroPHit project, the step-by-step approach, and ensuring that the fabric is upgraded first, the modelling of the proposals in PHPP v9 shows that each block meets the EnerPHit Standard in terms of specific heating demand as follows. | ||
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Further improvements will be investigated as part of the step by step approach for future implementation, | Further improvements will be investigated as part of the step by step approach for future implementation, | ||
- | **See also** \\ | + | ====== |
[[planning: | [[planning: | ||
[[phi_publications: | [[phi_publications: |
planning/refurbishment_with_passive_house_components/the_enerphit_standard_applied_to_large_complex_existing_buildings.1465206988.txt.gz · Last modified: by kdreimane