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Application of Expansion Elements

Expansion Elements for the roof drainage system…

Semmler Expansion Elements are ready-to-install expansion compensating units for roof drainage systems and for all types of gutters; water gutters, inserted box-type gutters, parapets, coping, flat roof skirting and wall joints.

…available in all metals generally used for roofing

We have been producing Semmler Expansion Elements for over 35 years. They are made from a high-quality rubber (EPDM) and can be employed in combination with all metals generally used for roofing, e.g. Titanium Zinc, Copper, Aluminium, Stainless Steel, Uginox FTE, pre-weathered Zinc etc. More detailed information about the various types of Semmler Expansion Elements and their application possibilities will be described on the following pages.

International distribution

Semmler Expansion Elements are in use not only in Germany but throughout Europe and in many other parts of the world. For an overview of application possibilities and our reference projects, please click on to Project Gallery. You will find detailed installation guidelines for Semmler Expansion Elements at Downloads.



Why use expansion elements?

Compensation of changes in length

All roofing materials are exposed to extreme fluctuations in temperature. A sudden rise or drop in temperature can occur within minutes, as caused by approaching thunderstorms or when the bright spring sunlight turns quickly to night frost. Building components expand or contract; each material reacts differently according to its natural properties. The location of the building plays a vital part. How much sunshine and how much shade are the building materials subjected to? The elements of nature change the make-up of the building components, they begin to creak and groan. Materials expand at different rates. The average expansion per metre at a difference in temperature of 100°C is as follows:

Concrete 1,2 mm Titanium zinc 2,2 mm
Sheet steel 1,2 mm Aluminium 2,4 mm
Copper 1,7 mm

Practical experience has shown that the soldered or bonded joints in bitumen roof-sheeting are especially vulnerable where such expansion is concerned. The use of expansion joints, which have an elastic central part, can systematically compensate for all such undesired changes in length.