Missfärgningar av träfasader : En studie av tre områden i Gävle

Sammanfattning: Building façades can be affected by mould, algae and cyanobacteria which, through their dark pigments in the cells, can cause discoloration on the façade. These organisms are affected, among other things, by the availability of water and the air humidity. Discoloration generally does not cause any damage to the building, just presents as an aesthetic problem. There are various ways to prevent the emer-gence of these organisms. However research has shown that with the wrong methods used an opposite effect can be received. The methods that are used can also present a hazard for the environment. A field study of three different areas in Gävle, Sweden was carried out, here an ocu-lar inspection was made to identify buildings affected by discoloration. The areas studied were Lexe, Brynäs and Bomhus. In total 50 building facades with discolo-ration were found displayed on 25 different buildings. In Lexe and Bomhus several houses were found with facades that were classified as having the degree of discolo-ration “very”. The degree of discoloration was based on how widespread the discolo-ration was and how clearly it was visible to the naked eye. It was divided into three categories: “little”, “moderate” and “very” discoloured. A theory why these two areas were highly affected is the fact that they contain more vegetation compared to Brynäs. The proximity to water and roads was also considered to have had an effect. But it has not been possible to indicate how much these three aspects have affected. North and west façades were affected to a greater extent compared to south and east facades. A survey was distributed to everyone in the area. In the survey, respondents had to answer questions about discoloration. This to study how house owners feel about the problem. The response rate was low and only 33 responses were received. Hence, the survey not being as reliable as the sample size is small. But from the re-sponses that came in, it could be deduced that the majority wasn’t worried about di-scoloration. Even if they personally had been affected or currently dealt with the problem of discoloured building facades. Six pictures of building facades were also shown, this to find out how many of the respondents would take action to fix the facade in question. The results showed that the answer generally did not depend on the size and extent of the facade that was affected but rather how visible the discolo-ration was. Which mainly is affected by the colour of the facade and the type of org-anism.