At the chimney, two elements that behave differently meet: the roof covering and the vertical structure. The flashing must take over the water flowing down from above and direct it onto the sheet metal. It is not enough to cover the gap. What matters is the arrangement of the aprons, the connection to the wall and maintaining an unobstructed drainage path. The detail must be adapted to the specific chimney and profile. First, the chimney type, its finish and its position relative to the sheet metal ribs are established. The detail looks different at a masonry stack than at a system penetration. The requirements for distance from combustible materials depend on the chimney type and its documentation. The sheet metal around the penetration does not replace these clearances.

In Poland, trapezoidal sheet for a carport roof is selected to suit the specific structure and loads, not merely the roof area. Readers should check the support spacing, roof pitch, location of the structure and the degree to which it is sheltered by walls, because an open carport responds to wind differently from a closed building. The structural designer or person responsible for the project should select the profile for snow and wind loads, also taking into account deflection and the method of joining sheets. Before buying, describe the carport's actual function to the seller rather than giving only its dimensions.