<p>Housing construction very close to the lake Mälaren has become very popular today. One potential problem with these houses is the influence of the sea climate. Unprotected buildings are affected by strong winds and precipitation. So for that reason, it is very important to make an accurate climate investigation and use it for decision-making during the planning of the new settlement.</p><p>It is very important with a good moisture protection regarding pelting rain, that is the combination of wind and rain. This is more important for buildings close to a lake, as this location normally means a higher exposure to wind. The location of the main bodies of the houses has an effect on the wind force between the houses. Some house parts are affected more than other, for instance curtain walls, bays, balconies and so on. These are problematic because of water and moisture that are moving in into joints and cavities in connections.</p><p>Bigger efforts than climate investigations are needed to get rid of the moisture problem.</p><p>The different actors that are involved in the construction project need to cooperate and focus on potential moisture problems during the complete construction process, not only during the production phase. It is also important that the construction workers have the knowledge on how to construct buildings that are moisture safe in practice.</p><p>According to investigations made, it appears that many of the moisture damages in buildings originate from the production phase because of incorrect construction components that are moisture-sensitive. But approximately 50% of the moisture problems derive from the planning process. The reasons are mainly lack of easily available tools, (for instance descriptions of moisture protection), insufficient knowledge, lack of time and lack of interest. These early mistakes results in later problems during the production phase. It is of great importance that the project members have good communication with the building contractors. They need to inform them on how to calculate dry times for different construction components and what type of inspections that shall be performed.</p>

Housing construction very close to the lake Mälaren has become very popular today. One potential problem with these houses is the influence of the sea climate. Unprotected buildings are affected by strong winds and precipitation. So for that reason, it is very important to make an accurate climate investigation and use it for decision-making during the planning of the new settlement. It is very important with a good moisture protection regarding pelting rain, that is the combination of wind and rain. This is more important for buildings close to a lake, as this location normally means a higher exposure to wind. The location of the main bodies of the houses has an effect on the wind force between the houses. Some house parts are affected more than other, for instance curtain walls, bays, balconies and so on. These are problematic because of water and moisture that are moving in into joints and cavities in connections. Bigger efforts than climate investigations are needed to get rid of the moisture problem. The different actors that are involved in the construction project need to cooperate and focus on potential moisture problems during the complete construction process, not only during the production phase. It is also important that the construction workers have the knowledge on how to construct buildings that are moisture safe in practice. According to investigations made, it appears that many of the moisture damages in buildings originate from the production phase because of incorrect construction components that are moisture-sensitive. But approximately 50% of the moisture problems derive from the planning process. The reasons are mainly lack of easily available tools, (for instance descriptions of moisture protection), insufficient knowledge, lack of time and lack of interest. These early mistakes results in later problems during the production phase. It is of great importance that the project members have good communication with the building contractors. They need to inform them on how to calculate dry times for different construction components and what type of inspections that shall be performed.

One purpose of this work was to examine if a modification of the exterior insulation finishing system can lower the number of outer walls damaged by damp. The modification is the cut of the cellular plastic which is 45 degrees instead of a horizontal cut. One other purpose was; is cellular plastic or mineral wool better as insulation to minimize the dampness in this type of outer walls? A third purpose was to examine if there is any difference of dampness in the outer walls if using a gravel bed or concrete stones next to the outer wall. To examine these three purposes a laboratory experiment with three test walls with an exterior insulation finishing system was built. The difference between the three walls was the insulation. One wall was built with mineral wool with a horizontal cut, one with cellular plastic with a horizontal cut and the third with cellular plastic with a cut of 45 degrees. Simulations of pelting rain and measurements of dampness were carried out for 21 days. The measurements were taken at the same time every evening. After 21 days small samples of tree from the walls was weight, dried in an oven and then weight again to get the quantity of moisture in the samples before they were dried. A diffusion calculation of two outer walls, one with cellular plastic and one with mineral wool, was completed to examine the difference between the relative humidity in the walls. An identical calculation without a plastic film was executed too. The result of the calculations showed a minimal difference in the walls built with a plastic film. When the film was removed the result presented critical values. The result of the laboratory experiment indicates that the test wall with the cut of 45 degrees is better than the walls with a horizontal cut of the insulation. The differences were minimal but possible to read. Some critical, too high, values regarding the moisture content in wood were found and they came from the sills in the walls that had insulation with horizontal cuts. Of the two insulation types the result of calculations and laboratory experiment shows a minimal difference but they both indicates a better result for the mineral wool. The conclusion of this work indicates that cellular plastic with a 45 degree cut is slightly better than the horizontal cut. The comparison of cellular plastic and mineral wool indicates that the mineral wool is better. Another conclusion of this work is that the material on the ground next to the outer wall did not alter the dampness in the wall.