Stor förvirring råder kring hur lufttätheten ska mätas i flerbostadshus. De metoder som finns och de resultat som erhålls vid täthetsprovning av småhus är inte alltid applicerbara på flerbostadshus även om mätenheterna är de samma. Detta föranleder problemställningen för detta examensarbete: Varför och hur kontrolleras lufttätheten i ett flerbostadshus på ett praktiskt tillämpbart sätt, som också gör det möjligt att jämföra resultat från olika objekt? Metoderna som används för att undersöka detta är litteraturstudier och samtal med erfarna personer, samt demonstration av en mätmetod i fullskala. En diskussion med initiativtagarna till detta examensarbete leder fram till en rekommenderad metod och en mall för hur detta ska utföras. Byggnadsskalets luft-, diffusions- och vindtätning har stor betydelse för en byggnads energianvändning, fuktsäkerhet, termiska komfort och hygien, luftkvalitet, ljudmiljö, spridning av brand samt spridning av luftföroreningar utifrån och in. Lufttätheten är en avgörande faktor både för konstruktionens beständighet och för en god innemiljö i moderna byggnader. Lufttäta hus är dessutom lönsamma i längden för de inblandade aktörerna. På lång sikt även för miljön. Studier som gjorts visar att en byggnads energiåtgång för uppvärmning minskar med nästan 30 % om lufttätheten (egentligen luftgenomsläppligheten) förbättras från 0,8 l/s·m2 till 0,4 l/s·m2. En så stor minskning av energianvändningen kunde inte åstadkommas med andra energiförbättringsåtgärder som undersöktes. I Boverkets Regelsamling för byggande, BBR 2008 har kravet på lufttäthet tagits bort till förmån för ett funktionskrav för energianvändningen, under vilken lufttätheten faller in. Regelsamlingens allmänna råd hänvisar till standarden, SS-EN 13829 för bestämning av luftläckage. De metoder som idag finns att tillgå för att mäta lufttätheten hos byggnader är spårgasmetoden, täthetsprovning med provisorisk vägg, det egna ventilationssystemet, med mottryck i angränsande utrymmen samt med tryckdörr. Den sistnämnda metoden provades på flerbostadshus i Umeå med goda resultat. Observera att resultatet för denna rapport är en mall för mätningsförfarandet och den rekommenderade metoden för att mäta lufttäthet inom NCC i Umeå. Den beskriver en praktiskt tillämpbar metod där resultatet går att jämföra mellan olika objekt. Även en intern mätstorhet som beskriver ytterväggens täthet är framtagen. Mätstorheten och standardens relevans diskuteras. Ändringen i BBR från specificerade krav till funktionskrav anses vara kunskapsdrivande. Det förfarande som beskrivs i resultatet har bedömts vara det mest optimala under rådande förhållanden med den standard som finns. En förändring av standarden skulle kunna leda till en bättre metod som ger mer informativt resultat. / There is a great perplexity about how air permeability should be measured in multiple-unit dwellings. The methods available and the obtained results for determination of air permeability in single-dwelling houses are not applicable for multiple-unit dwellings, even if the derived quantities are the same. This causes the problem for this report: Why and how should the air permeability be determined for a multiple-unit dwelling in a functional and applicable way, which also makes it possible to compare the obtained results from different dwelling units? The methods used to explore solutions are literature studies, conversation with professionals and a full-scale demonstration of one of the methods. A discussion with the initiators of this report leads to the recommended method and a model for how it should be performed. The air-, diffusion- and windtightness of the building envelope are of big importance to the building. The use of energy, moisture transfer, thermal comfort and hygiene, air quality, noise, spreading of fire and spreading of air pollutions are all affected by it. The air tightness is a crucial element for the durability of the building and to secure a good indoor environment. Air tight buildings are also cost-effective in the long run for the involved participants. They are also good for the environment. A study that have been made show that the energy-use for heating buildings will be reduced with almost 30 % if the air permeability improves from 0,8 l/s·m2 to 0,4 l/s·m2. Such a big reduction of the energy use could not be accomplished with any other energy improvement-move that was investigated in the study. The Swedish building regulations, Boverkets Regelsamling för byggande BBR, used to have a demand for the air tightness of buildings. It has been removed in favor of a demand of the function for the energy use, which also include the air tightness. The common advices in BBR refer to the standard, SS-EN 13829 for determination of air permeability. The methods available for determination of air permeability in buildings are the tracer-gas method, determination with a temporary wall, the ventilation system, with corresponding pressure in adjacent spaces and determination with a Blower Door. The last method was demonstrated in multiple-unit dwellings in Umeå, Sweden, with good results. Note that the result of this report is a methodology and how the method should be performed within buildings erected by NCC in Umeå. It describes a functional and applicable method where the results can be compared between different objects. An internal quantity which describes the air permeability of the external wall has been developed. A discussion of the relevance if the derived quantity and the standard has been made. The change in BBR to demands of the function for the energy use has been considered to be a driving force for knowledge. The procedure described in the results has been considered to be the optimum procedure for existing conditions with the standard available. A change in the standard would lead to a better method which would give more informative results.

För att skapa ett bra inomhusklimat i flerbostadshus ställs höga krav på ventilationssystemet för att ta hand om den fukt som skapas. Det finns således anledning att undersöka om Boverkets byggreglers krav för minsta luftflöde är tillräckligt ur fuktsynpunkt. Syftet är att uppmärksamma problem med ökande fukttillskott i nyproducerade flerbostadshus vilket skulle kunna förändra projekteringen av ventilation i framtiden. För att kunna undersöka om Boverkets byggreglers krav är tillräckligt ur fuktsynpunkt analyseras relativ fuktighet och fukttillskott i fyra flerbostadshus i Jönköping. Det framgår att flera lägenheter erhöll höga värden för fukttillskott och relativ fuktighet vilket kan skada byggnaden och påverka människors hälsa. Boverkets byggreglers krav för minsta luftflöde var otillräckligt ur fuktsynpunkt i flera av de undersökta flerbostadshusen. / To create a good indoor climate in apartment buildings, high demands are made on the ventilation system to take care of the moisture that is created. There is therefore reason to investigate if Boverket, the Swedish National Board of Housing, Building and Planning, requirements for minimum airflow are sufficient from a moisture point of view. The purpose is to rise awareness about increasing additional moisture in newly built apartment buildings, which could change the project planning of ventilation systems in the future. In order to investigate whether requirements of the Boverket building regulations are sufficient from a moisture point of view, relative humidity and additional moisture were analyzed in four apartment buildings in Jönköping. Several apartments received high values of additional moisture and relative humidity which could damage the building and affect human health. The requirements of Boverket building regulations for minimum airflow should therefore be reviewed.

Purpose: Villas built before 1960 represent around 45% of the dwelling in Sweden. Since the average U-value in their walls is around 0,5 W/m2K, there is a great concern to improve  these values. The Swedish government's goal is to reduce energy intensity in the country by 2020 by 20 % from 2008’s values. The aim of this study is to reach phase renovation proposals taking into account energy and moisture on houses consisting of standing shelves. With this, the authors wish to contribute and encourage renovation of existing villas, which in turn can lead to reduced energy consumption. Method: This work is based on a case study of a 1940’s wooden house located in Skillingaryd. Measurements and parameters have been taken in order to calculate the house's specific energy usage in the BV2 analysis program. Document analyses and interviews have been used to get a deeper knowledge of existing conditions, and to suggest ways to utilise the material that the market offers nowadays. This should serve the purpose of creating as energy-efficient phase resolution as possible. Result: The study shows that an outer wall of a massive wooden house should keep a U-value of 0,15 W/m2K to meet the specific energy consumption of 90 kWh/m2 and year, when the other house is additional insulated. The study presents two refurbishment proposals supported by interviewed experts in the insulation and consulting industry. The first option leaves large parts of the old facade untouched, adding new insulation layers of the desired thickness. The second option advises to tear away all old panels into the shelf frame, thus re-building with new materials. Both proposals address the issue of how the facade should be refurbished in order to make it moisture proof. They mostly solve the problem by refurbishing it outwards and by eventually placing a vapor barrier for a maximum of one third in of the insulation. This vapor barrier may or may not be a watershed according to the experts. Some think it is unnecessary when the plank is considered sufficiently diffusion-proof; some believe that it will help to identify where a possible condensation might occur in the wall.  Consequences: The study shows that by means of additional insulation, BBR 24 recommended values ​​can be achieved for an exterior wall while keeping the façade moisture proof. One strength the study shows that the two reported renovation proposals achieve the same end result, although the interference on the facade varies in size. Therefore the authors of the above study recommend to tear down the old facade and build a new control wall with a finishing facade disc. This is when you face a vapor barrier on the façade with a vapor barrier that is laid on the old baselayer of the roof. Then a new roof construction could be built up with roof beams, shavings and roof tiles. As a result, a windy, yet proportional, construction can be created.   Restrictions: The study assumes that the entire house would be refurbished in order for the specific energy use to be possible. Furthermore, the work is based of a shelf shelter located at a particular geographical site. Due to this, the study also offers suggestions on wooden facades only.  Keyword: Plank body, Phase renovation, Specific energy use, diffusion, convection, U-value, air density.