Roof renovation for sheet metal roof (trapezoidal sheet or corrugated sheet) in industry
Sheet metal roof renovation, here using the example of a 10,000 m² warehouse.
The task was to insulate the roof as part of a change of use and to install 52 skylight domes, designed as SHEVS, as part of the building requirements.
Of particular importance here was the prevention of condensation under the trapezoidal sheet metal roof.
Before the renovation work, the roof was not insulated. The unimpeded effects of heat and cold meant that some of the fastening screws had broken off due to shear forces resulting from longitudinal elongation of the sheets. Other screws pulled elongated holes in the sheets due to the same effect. There were countless small leaks.
After installation of the skylight domes, the roof was foamed in several layers with in-situ polyurethane foam.
The skylight domes were installed and foamed on properly and professionally. The foaming eliminated all leaks.
In order to coat the roof profile evenly with foam, the sheets are foamed on from two sides. It is particularly important that the first layer is coated with the direction in which the sheets are laid. The outside temperature plays an important role in the foaming process. The higher the ambient and substrate temperature, the better the foam.
Particularly in the case of sheet metal roofs, care must be taken to ensure that the substrate temperature is high enough, at least 12°C. Otherwise, the reaction heat of the foam taken from the cold sheet metal prevents optimum foaming.
A liquid plastic in the color silver-gray or gray was sprayed onto the finished foam surface to protect it from UV exposure and to protect it from "bird pecking".
In this project in Hamburg, in addition to the unpredictable weather there, the situation was aggravated by the fact that the humidity, which should not exceed 70 % rel. during foaming, rarely fell below the limit values.