What is chimney flashing? The GZK system explained


11th Nov 2020 Property

What is chimney flashing? The GZK system explained

Professionally executed chimney flashing should guarantee a tight connection between roofing and a chimney duct. Moreover, an important issue is the aesthetic execution of the flashing, which will affect the final appearance of the roof surface. Particularly noteworthy are new solutions in roofing work, which guarantee aesthetics and tightness, such as the GZK system chimney flashing. What is worth knowing about the GZK system and how to properly perform chimney flashing?

The tightness of the roofing depends on the flashing of the chimney, therefore you should pay great attention to the precise installation. Chimney flashing not only protects the chimney duct against rainwater, but also protects the interior of the house against leakage.

Which material should you choose for chimney flashing?

The flashing of a chimney is most often performed using flat sheets made of copper, steel, aluminium, galvanized or titanium-zinc. When choosing a material for connecting the chimney with the roof, it is worth considering the type of roofing both in terms of aesthetics and functionality. In case of roofs covered with sheet metal or tile roofing, it is advisable to use chimney flashings made of the same materials, which will have the same durability. However, if the roof has been finished with ceramic tiles, whose durability is estimated to be even 100 years, for flashing it is worth choosing a material that will be equally durable. In this situation, it is best to use high-quality thick coated sheets. GZK system chimney flashing will also be a good choice. The chimney flashing system creates a flexible sealing flashing made of aluminium sheet and protected by modified polyester, which guarantees high durability and resistance to the destructive effects of atmospheric factors. 

How to perform a flawless chimney flashing?

The chimney flashing consists of four elements – the front, rear and two side strips, all of which form one or two layers of sheet metal. The sheet metal work starts with putting tar paper or pre-coating foil on the chimney. Then, from the strips of a metal sheet a flashing is formed, which should protrude at least 15 cm above the roofing. The fragment of the flashing on the roofing must be at least 10 cm wide and at least 20 cm from the rooftree side. Sealing is done by cutting holes in the chimney duct walls and placing the prepared strips of sheet metal in them. Tight chimney flashing is guaranteed by the use of roof sealant where the chimney is connected to the flashing. Correctly performed chimney flashing involves precise adjustment of the shapes and sizes of metal strips to the shape of the chimney duct and roofing. Finishing the connection between the chimney and the roof with metal sheets is quite a demanding task, so it is worth commissioning such works to an experienced roofer.

How to perform GZK system chimney flashing?

Easy and quick to install GZK system chimney flashing guarantees both tight and aesthetic connection of the chimney duct to the roof. The flashing can be used for roofs with a pitch between 15 and 70 degrees, covered with any type of roofing. The GZK system provides universal and fixed chimney flashing. In the first case, thanks to adjustable elements of the system flashing, we can apply to chimneys with a maximum width of 95 cm and length of 180 cm. The GZK chimney flashing, on the other hand, is used to seal chimney ducts with fixed dimensions – a width of 38 cm and a maximum length of 100 cm or a width of 51 cm and a maximum length of 100 cm. The use of the GZK system chimney flashing is also possible in case of chimneys longer than 180 cm. Then an additional GZK lengthening module should be used, which allows to increase the length of flashing by at least 100 cm.

Chimney flashing is one of the most difficult and at the same time most important roofing works. The place where the chimney duct is connected to the roof is particularly exposed to the occurrence of leaks, through which rainwater or snow can get into the building. That is why it is so important to have a reliable and tight chimney flashing, where it is worth applying modern system solutions.