Refurbish a building built in 1959 that had received an addition on the west end in 1969, gutting the structure and removing several walls in favour of larger, more open spaces and replacing windows, some larger. The roof insulation and the 240-mm masonry walls were not up to today’s energy and living standards.
Open the roof and install a vapour-permeable, retarding membrane over the exterior face of the interior boarding and up and over the rafters into the next cavity, plus GUTEX Thermoflex® (120 mm), a flexible batten insulation, between the existing rafters. GUTEX Ultratherm®, installed over the rafters, forms a rain- and wind-tight sub roof. GUTEX Ultratherm® was also used to insulate the dormers. GUTEX Thermowall® ETICS with 140-mm insulation was the choice to clad and insulate the existing masonry. White-painted render finished the exterior wall faces.
Additional improvements included a heating system fired by oil or split firewood with radiant floor heating; 10 m² solar thermal collectors with 1,000-litre storage capacity; modern wood-burning stove and a new electrical system.
Building footprint: 158 m²
Heated house volume: 713 m3
Net floor area: 228 m2
Annual primary energy source usage (as per EnEV abbr.: QP): 25.8 kWh (m2a)
Annual heating usage* Qn: 70.45 kWh/ m2a
Heat transfer/loss (HT): 0.31 W/ (m2K)
Windows U-value: 0.9 W/ (m2K)
Roof U-value: 0.177 W/ (m2K)
Walls U-value: 0.252 W/ (m2K)
* Annual heating usage = loss through roof, windows, exterior walls + energy required to heat cold air due to ventilation – internal heat gain via solar, appliances, etc.
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