In a 4 story multi-owner house in Rotterdam, the Netherlands there is an 80mm semi-rigid aluminum duct like the one shown in the image below which contains the water heater exhaust of my neighbors who live below. Since I have made structural changes to the roof this duct needs to be extended. Ideally, it can connect with a rigid pipe that can then connect with the roof exhaust.
I cannot find a piece to provide a mechanical connection from this semi-rigid pipe to a rigid pipe. Do you have any suggestions?
Is there any reason why the following hack wouldn’t work?
The 80m semi-rigid pipe is placed inside a minimum of 50mm distance inside a 90mm rigid aluminum pipe. Griffon HBS-200 (a universal, durable, water and airtight and protective sealant) is used to seal the connection. Vaster Aluminium Tape then wraps the entire connection. This detail is sketched in the image below.
Questions
- What connection should I use (if you can share products from other countries I can look for their equivalent in the Netherlands)?
- Is my hack a stupid idea and why?