new build PROJECT OVERVIEW: Building type: 270 sqm detached two storey masonry house Location: 1 Magner Avenue, Churchfield, Castlemagner, Mallow, Co Cork Completion date: May 2013 Budget: €270,000 (including finishes) Passive house certification: pending Space heating demand (PHPP): 14 kWh/m2/yr Heat load (PHPP): 9 W/m2 Primary energy demand (PHPP): 74 kWh/m2/yr Airtightness: 0.54 ACH at 50 Pa BER: 52.83 kWh/m2/yr Thermal bridging: Last two courses of deadwork are Quinn Lite blocks, 50mm edge insulation strips, no internal partition foundations (stud work only), low thermal conductivity cavity wall ties – Ancon TeploTie 2, thermally broken window frames – Ecotherm Plus Passiv certified windows and doors, insulated reveals (no cavity closing blocks, no wallplate closing blocks, door threshold bridging detailing. Y-value (based on ACDs and numerical simulations): 0.08 W/mK Ground floor: Standard strip foundation using Quinn Lite thermal blocks in the last 2 rows of deadwork, 50mm edge insulation strips, 200mm Kingspan Thermafloor insulation: Uvalue: 0.112 Walls: 100mm external block, 300mm cavity using Ancon TeploTie 2 basalt wall ties, 100mm inner block, hard coat and skim finish. U-value: 0.106 Roof: Cupa H5 Natural slates externally on 50x35 battens/counter battens, followed underneath by breathable roofing underlay, 450mm cellulose on flat of attic: U-value: 0.096 Windows: Passive House Institute certified Munster Joinery Ecotherm Plus Passiv windows, with PVC frame and aluminium cladding internally and externally. Subject to window size, U-values range from 0.47 to 0.78 Heating system: Nilan Compact P air to air heat pump combining heat recovery ventilation, 2 KW in duct booster heat element, active cooling module, 180 litre domestic hot water tank. Secondary heating system is an Extraflame Duchesa wood chip pellet stove with back boiler feeding 5 radiatiors throughout the house.
On the subject of build cost, he has this to say. “For a standard A-rated build, you’re looking at €80 or €90 a square foot. If you were to take that same building and make it passive, you’re looking at between €90 and €100 a square foot. There could be little or no difference, or there could be quite a difference depending on the design of the house.” SELECTED PROJECT DETAILS Client: Larry O’Donoghue Architect (design & planning): Feargal Sheahan Civil & structural engineering: TGL Consulting Engineers Energy consultant: Passive House Design Contractor: Magner Homes Mechanical contractor: Kevin O’Donoghue Plumbing & Heating Services Electrical contractor: A&J Electrical
Airtightness installer: Magner Seal Airtightness tester: Collins Energy Consultants Cavity wall insulation: Envirobead Cellulose insulation: Warmcel Floor insulation: Kingspan Airtightness products: Siga, via McMahon Building Suppliers Windows and doors: Munster Joinery Air source heat pump & ventilation: Nilan Wood pellet stove: Kerry Biofuels
Ventilation: Nilan Compact P air to air heat pump combining heat recovery ventilation, 2 KW in duct booster heat element, active cooling module, 180 litre domestic hot water tank
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(above) Siga tapes and Intello membranes help to ensure the house is airtight, one of the main objectives in the build; (p43, top to bottom) thermal bridging strategies included the omission of a cavity closer; TeploTie basalt wall ties; and insulated window reveals.
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