Inverkan av skruvars installation på fuktinträngning i trä

Sammanfattning: Wood and wood-based materials are common materials used in buildings, both in- and outdoors. However, wood is vulnerable to water and moisture which is why it is essential to keep it dry and prevent moisture from getting into the wood. Thus, there are multiple methods to protect the wood against moisture, such as using paint, oil, impregnation, or different metal profiles. Fasteners penetrating wood can act as a passage for water to be absorbed deeper into the material and increase the moisture content which results in decreased durability and reduced mechanical properties. This report investigated if differences in the installation depth of screws and the moisture content of the penetrated wood correlate. It was executed by measuring moisture content continuously on 48 small samples made of spruce that had been placed on a roof where the samples were exposed to the weather for two years. These specimens had one screw each which was installed in three different ways, either with the screw head being above, flush, or below the wooden surface. The results were then analyzed and compared with precipitation to find patterns. The results were scattered and inconclusive which made it difficult to draw a conclusion. Even though the results were inconclusive, some results made it clear that poor installation led to an increase in moisture content. The scattered results could be due to variations in the wood, practical problems with the sensors, or a limited testing period. Thus, more testing is needed with more samples.