Dear forum members,
Since 2015, we have been living in a prefabricated house (timber frame construction). Recently, we had an external stainless steel chimney retrofitted.
For this, a wall opening with a diameter of about 20-25 cm (8-10 inches) was created.
A Schrader Coolblock was installed for the chimney pipe. The chimney pipe passes through this block.
We had to cut through the vapor barrier for this. Now my question is, how can I properly seal this barrier again?
The barrier is installed about 3 cm (1 inch) deep from the interior wall. First comes the drywall, then a chipboard panel, and then the vapor barrier.
We would essentially need to close it around the chimney pipe. The opening was made cleanly, meaning the vapor barrier edges would have to be exposed by carefully removing drywall and chipboard to reveal some of the membrane, so that an additional piece of vapor barrier could possibly be glued on with sealing tape.
After that, a round piece of drywall and a round piece of chipboard (in the shape of a donut) would need to be installed. Here I am wondering how I can properly install and bond these two pieces?
Lots of questions — from the outside, the opening is well insulated, but the inside work must be done by us.
P.S. Currently, the vapor barrier is open over a 20 cm (8 inch) area. Moisture shouldn’t be a problem. I assume it needs to be sealed as soon as possible, right?
Best regards
Since 2015, we have been living in a prefabricated house (timber frame construction). Recently, we had an external stainless steel chimney retrofitted.
For this, a wall opening with a diameter of about 20-25 cm (8-10 inches) was created.
A Schrader Coolblock was installed for the chimney pipe. The chimney pipe passes through this block.
We had to cut through the vapor barrier for this. Now my question is, how can I properly seal this barrier again?
The barrier is installed about 3 cm (1 inch) deep from the interior wall. First comes the drywall, then a chipboard panel, and then the vapor barrier.
We would essentially need to close it around the chimney pipe. The opening was made cleanly, meaning the vapor barrier edges would have to be exposed by carefully removing drywall and chipboard to reveal some of the membrane, so that an additional piece of vapor barrier could possibly be glued on with sealing tape.
After that, a round piece of drywall and a round piece of chipboard (in the shape of a donut) would need to be installed. Here I am wondering how I can properly install and bond these two pieces?
Lots of questions — from the outside, the opening is well insulated, but the inside work must be done by us.
P.S. Currently, the vapor barrier is open over a 20 cm (8 inch) area. Moisture shouldn’t be a problem. I assume it needs to be sealed as soon as possible, right?
Best regards
karlleutz schrieb:
Hello everyone,
thank you for your contributions.
So, I’ve made some progress...
- The company I hired has an excellent reputation, and they are usually reluctant to provide offers for prefabricated houses.
- I looked up the silver foil, and the material also seems reliable in terms of quality. Here are the product’s features:
Advance offers a wide range of foil tapes with acrylic adhesives that increase their adhesion over time but can be removed if left on only for a short period.
Our tapes have been developed for various applications and guarantee additional performance and resistance to extreme temperatures.
Advantages:
• Provide excellent adaptability
• Are water-repellent and offer a complete vapor barrier
• All Advance foil tapes have a white silicone-coated release liner and unwind very easily
• All Advance tapes are fully tempered and as soft as the manufacturing processes allow
• All adhesive tapes are easy to tear
... I can understand well why hardly anyone wants to make penetrations through a wall structure with thick external thermal insulation composite systems (ETICS). We had to create several penetrations in the exterior wall ourselves during the shell construction phase (for example, for the controlled residential ventilation system, externally on the wall up in the first insulation layer). This required a massive effort using separate boxes made of film-faced plywood, which were then sealed vapor-tight and additionally foamed. The same had to be done again because our electrician, unfortunately, failed to inform us in time: we should install a drainage pipe (e.g., a sewer pipe) from the technical room to the utility room for the thick electrical cables since they are not allowed to run under the bathroom otherwise. (Of course, as homeowners coordinating the work ourselves, we are to blame here, but it would have been nice if he had told us in time.) So, again, building boxes around the pipe, etc. That’s the story...
Regarding your tapes, everything sounds fine, but I see nowhere that they are approved or suitable for attachment onto finished external render/plaster. That is exactly the crucial point: how can a smooth tape create a watertight seal on the crumbly texture of exterior plaster? Well, it can’t. That only works in combination with, for example, the cartridge sealant I mentioned earlier (which is also used for vapor barriers) plus the tape. Whether the whole system then appeals to the home builder as a complete solution is another matter. If the warranty becomes void because of this (which I currently assume) and if you then have moisture or heat damage at that spot – well, good luck dealing with that.