<p><strong>Abstract</strong></p><p>This report intends through a case study to investigate if lightweight concrete is</p><p>appropriate as main material in the outer wall of a seven storey residential building.</p><p>A technical design is carried out in accordance with the definitions and requirements</p><p>for passive houses, given by FEBY’s1 <em>“Demand specification for passive houses”</em>.</p><p>A literature review is also carried out for a comparison between regular bolt wall and</p><p>light weight concrete wall, with a focus on the safety of moisture.</p><p>The lightweight concrete block used in the report is as a celblock produced by the</p><p>company H+H Sweden AB.</p><p>The methods used have resulted in compliance with requirements and</p><p>recommendations from authorities. Calculations of energy, noise and moisture risk</p><p>assessment has been carried out.</p><p>The work has resulted in the conclusion that the lightweight concrete itself is not</p><p>able to isolate in the extent necessary to obtain chosen U-value of 0,1 W/m2 ° C,</p><p>without getting to thick. Therefore additional insulation is needed. There are few</p><p>relevant reference objects built with only light weight concrete. A villa in Lomma,</p><p>Sweden, has been designed but is not yet built. The house has no additional</p><p>insulation and the climate screen consists only of light weight concrete and plaster.</p><p>The multi storey building designed within this report has generally large windows,</p><p>also to the north, which in passive house context is unusual. The large window areas</p><p>result in greater thermal bridges around the windows and greater losses of heat</p><p>through transmission.</p><p>As compensation a very low U- value of 0,1 W/m2 ° C was set as a prerequisite from</p><p>the start ensuring a positive energy balance. This action has proved necessary when</p><p>implemented energy balance calculation resulted in the heating demand of 42</p><p>kWh/m2 per year. Maximum allowable energy for a passive house is according to</p><p>FEBY under 50 kWh/m2 per year.</p><p>There are several advantages identified when using light weight concrete. All</p><p>problems related to moister are avoided with this completely mineral material. Light</p><p>weight concrete offers good thermal insulation by its porosity. It has heat storing</p><p>properties during the winters. The material is fireproof and free from chemicals.</p><p>Together with additional insulation a quiet and healthy indoor environment is</p><p>derived.</p><p>It has been difficult to find potential risks of using concrete in the climate screen of</p><p>a passive house. Passive house technology is relatively new, and passive house</p><p>technology with concrete is even newer. In fact, the villa in Lomma is said to be the</p><p>first in Sweden carried out in light weight concrete. A minor estimation upon the</p><p>costs of a the insulated light weight concrete wall, contra a wood bolt wall has proved</p><p>the light weight concrete wall to be twice as expensive. Perhaps the future will prove</p><p>risks that have not yet been revealed?</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:hj-12877 |
| Date | January 2010 |
| Creators | Sundemo, Sörensson, Malin, Frederic |
| Publisher | Jönköping University, JTH, Civil Engineering |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, text |
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