Hi!
I'm working on decorating the upstairs. I realized a bit too late that the electrician didn't bother to seal all the conduits of the flex pipes through the age-resistant plastic. Now I've already put up all the drywall and almost all the ceilings, and I have a nagging feeling that I should have done this. What do you think? Is it necessary to take down all the drywall and ceilings to tape, or how critical is this?
What type of age-resistant tape should be used in that case? I can't find one that really matches the need. How do you handle the penetration of the smoke pipe? Does it get too hot for the tape if you tape against the pipe?
Grateful for any help!!
I'm working on decorating the upstairs. I realized a bit too late that the electrician didn't bother to seal all the conduits of the flex pipes through the age-resistant plastic. Now I've already put up all the drywall and almost all the ceilings, and I have a nagging feeling that I should have done this. What do you think? Is it necessary to take down all the drywall and ceilings to tape, or how critical is this?
What type of age-resistant tape should be used in that case? I can't find one that really matches the need. How do you handle the penetration of the smoke pipe? Does it get too hot for the tape if you tape against the pipe?
Grateful for any help!!
Hi,kungkokos said:
a few counter-questions:
- Is it a new build?
- Is it an insulated chimney pipe?
If it's a new build, I'm quite convinced that you should have taped or sealed penetrations. If I were in your shoes, I wouldn't pay the electrician what he asked for, but ask for a price reduction. Granted, you've been a bit too hasty putting up drywall and ceiling panels, but in my eyes, a competent electrician should seal the penetrations he makes without you, as a layman, having to remind him of it. So, in other words, I think it's primarily his blunder, not yours.
Further, you should probably forget about taping around the chimney. If you have a similar type of chimney to mine (insulated pipe), you should use a heat-resistant rubber membrane as a seal between the chimney pipe and the vapor barrier. Unfortunately, I received my rubber membrane late due to my supplier's ignorance, so I had to cut it apart to fit it onto the chimney pipe which was already installed. It worked out fine after much ado, but I had to use a lot of silicone and other tricks to make it work. The simplest way, of course, would have been to slip the rubber membrane on during the installation of the chimney pipe, not afterward. I recommend you call and consult both your local chimney sweep, who will eventually issue the burning permit, and also the manufacturer of the chimney.
It's not an ideal situation you've found yourself in and I hope you don't have too many penetrations upward through the ceiling.
Finally, regarding tape: I have used an age-resistant tape (3M) which can be bought at Beijerbygg. It's good but very expensive. Additionally, I'm somewhat disappointed that it comes off too easily from the construction film. But, once you've put up ceiling insulation and the inner roof, it should press on and thus hold.
Hello! It's a new build with an unfinished upper floor, but with a sparse and plastic-covered spray-insulated attic within the total contract. In hindsight, I might have rushed things a bit with installing drywall and the ceiling. I've spent time looking at photos, and I think I don't need to worry too much about the electrician's work in the ceiling, but I am quite certain there are some penetrations in the slanted ceiling outward. These are probably not sealed because they are not the penetrations in the bathroom where I haven't installed the aquapanel.
However, I have just discovered that the carpenters have plasticized the ceiling very sloppily, so now insulation is leaking in one spot in the ceiling... not great! So now it's not sealed anyway. I wonder how it looks in all the other places where I've installed the ceiling...
Then I read on Gyproc's website that a spackled and sealed drywall constitutes a "vapor barrier" in itself because it is so tight. No air can migrate. So maybe the external penetrations will resolve themselves? Should I still remove the drywall to be sure?
The chimney pipe and the ventilation duct are probably uninsulated, but this only matters for the distance to combustible material, right? I saw that Contura recommends their diffusion protection + aluminum tape. The chimney sweep has already issued a permit for use in the existing condition. The ventilation duct is also approved even though it's sparsely a maximum of 1 cm from the pipe. According to the requirements, it should be 3 cm from ventilation ducts to combustible material. How should one seal that penetration?
Sigh!
How should I proceed now?
However, I have just discovered that the carpenters have plasticized the ceiling very sloppily, so now insulation is leaking in one spot in the ceiling... not great! So now it's not sealed anyway. I wonder how it looks in all the other places where I've installed the ceiling...
Then I read on Gyproc's website that a spackled and sealed drywall constitutes a "vapor barrier" in itself because it is so tight. No air can migrate. So maybe the external penetrations will resolve themselves? Should I still remove the drywall to be sure?
The chimney pipe and the ventilation duct are probably uninsulated, but this only matters for the distance to combustible material, right? I saw that Contura recommends their diffusion protection + aluminum tape. The chimney sweep has already issued a permit for use in the existing condition. The ventilation duct is also approved even though it's sparsely a maximum of 1 cm from the pipe. According to the requirements, it should be 3 cm from ventilation ducts to combustible material. How should one seal that penetration?
Sigh!
How should I proceed now?
Hello again.
I get a little confused when I read your email, it feels like there are some things that haven't been properly done. It also seems there is quite a difference between municipalities in Sweden regarding what the chimney sweeps consider okay or not. Mine was adamant that the distance between the extraction channel and combustible materials should be 30mm and that there should be a fireproof mat around the pipe where it goes through the intermediate joist and up to the roof vent. The same with the chimney, but there the requirement was 50mm to combustible materials and stone wool instead of regular yellow fiberglass insulation.
Since we are self-builders, we could afford to be meticulous with the vapor barrier. We have been careful with overlaps, taped properly, and used approved tape. We have both siliconed and taped the fittings. The reason for all this (maybe somewhat excessive fussing with the vapor barrier) is that I have perceived it as important to avoid future mold problems. We have both designed and built a modern wooden house in turn-of-the-century style with a proper insulation shell and reduced the house's energy consumption to 80kWh/m2, which can be considered very low. The downside of this is that nothing other than the sun will be able to heat up the attic and keep it dry. So that's why I felt that the attic should be protected from warm and thus humid air that can seep up from below. I have also made sure that the attic ventilation is generous.
The reason I am explaining all this is that I want you to understand my approach and why I think it's important to have a good vapor barrier shell for our house. As for your house, it seems there are quite a few gaps and holes in the vapor barrier shell. So it feels a bit overwhelming in my eyes to tear everything up at this point. You might want to monitor the situation in the attic over the next few years and take action if mold starts. There are ready-made anti-mold systems for attics. I can't remember the brand, but you apparently need to plug the ventilation holes and install a dehumidifier that then keeps the attic dry.
That's that. Good luck with your decision, and I'm sorry if I haven't given you the help you wanted. Maybe someone else can?
I get a little confused when I read your email, it feels like there are some things that haven't been properly done. It also seems there is quite a difference between municipalities in Sweden regarding what the chimney sweeps consider okay or not. Mine was adamant that the distance between the extraction channel and combustible materials should be 30mm and that there should be a fireproof mat around the pipe where it goes through the intermediate joist and up to the roof vent. The same with the chimney, but there the requirement was 50mm to combustible materials and stone wool instead of regular yellow fiberglass insulation.
Since we are self-builders, we could afford to be meticulous with the vapor barrier. We have been careful with overlaps, taped properly, and used approved tape. We have both siliconed and taped the fittings. The reason for all this (maybe somewhat excessive fussing with the vapor barrier) is that I have perceived it as important to avoid future mold problems. We have both designed and built a modern wooden house in turn-of-the-century style with a proper insulation shell and reduced the house's energy consumption to 80kWh/m2, which can be considered very low. The downside of this is that nothing other than the sun will be able to heat up the attic and keep it dry. So that's why I felt that the attic should be protected from warm and thus humid air that can seep up from below. I have also made sure that the attic ventilation is generous.
The reason I am explaining all this is that I want you to understand my approach and why I think it's important to have a good vapor barrier shell for our house. As for your house, it seems there are quite a few gaps and holes in the vapor barrier shell. So it feels a bit overwhelming in my eyes to tear everything up at this point. You might want to monitor the situation in the attic over the next few years and take action if mold starts. There are ready-made anti-mold systems for attics. I can't remember the brand, but you apparently need to plug the ventilation holes and install a dehumidifier that then keeps the attic dry.
That's that. Good luck with your decision, and I'm sorry if I haven't given you the help you wanted. Maybe someone else can?
Thank you for your post! I really appreciate having a sounding board. I completely share your view on vapor barriers, which is why I started this thread. My only problem is that I trusted that the carpenter, construction coordinator, and inspector were doing their jobs properly. My construction coordinator is coming here today to take a look at everything, so it will be interesting to hear his opinion. Regarding perforations in the exterior walls, he didn't think one needed to worry about sealing these. The vapor pressure outward behind plastered drywall is minimal. However, in the bathroom, you absolutely must not overlook this anywhere. Moreover, the tightness of the ceiling is more important because heated moist air travels upwards. Therefore, we will put extra energy into this and ensure that the large hole I found is sealed now that I am installing the ceiling. I have now acquired age-resistant tape to seal the holes, but I am still wondering how to seal around the duct and flue. The mineral wool on the vent is unlikely to act as a vapor barrier, especially around the flue where the air heats up directly and travels upward through the insulation.
Our house is also designed for 80kW/m2 excluding household electricity.
Our house is also designed for 80kW/m2 excluding household electricity.
Hello,
I will try to explain how I did it.
The chimney pipe (NVI 2000)
Through the intermediate floor, I have nothing at all, just mineral wool and at least 50mm to combustible material. Where the chimney pipe goes through the upper floor, I built a square frame around the pipe with 45x45 studs. The minimum distance is also 50mm to the pipe this time. I built the frame for two reasons: partly to have something to attach the ceiling to closest to the chimney pipe, but also to have something to attach the rubber sheet to. The rubber sheet was square with a hole in the middle that had a significantly smaller diameter than the chimney pipe, to ensure it seals properly. The outer dimensions of the rubber sheet were about 50x50cm if I remember correctly. Since I received the rubber sheet after the chimney was installed, pressure tested, and approved, I didn't want to disassemble the pipe sections to put on the sheet. So I had to cut the sheet and slide it on from the side. While I was at it with the scissors, I slightly increased the diameter to make the sheet somewhat easier to work with. We fastened the sheet against the pipe with straps and applied a generous amount of silicone to minimize the risk of leakage. That was the rubber sheet against the pipe. After this, it was time to attach it to the frame I built. There were two of us for this task since the rubber, for some reason, always wants to return to its original shape. So after a few curses, we managed to attach the rubber sheet to the stud frame in a stretched position and stapled it with a staple gun. After this, I smeared more silicone on the outside and then folded the vapor barrier over the rubber sheet and stapled it as well. I cut the vapor barrier about 50mm around the pipe, but it probably could have gone all the way forward.
Regarding the ventilation duct and the sealing between the fire mat and the sloped ceiling's vapor barrier, it was not as easy to seal and make the sealing good. It’s kind of in the nature of things that it becomes difficult to seal against the fire mat's "chicken wire." But I made it simple for myself. I took a rectangular piece of leftover construction plastic and wrapped it around the fire mat that was already on the ventilation duct. I made sure that the piece of construction plastic went a bit into the ceiling before I taped it tightly against the fire mat. Then it was just a matter of taping the vapor barriers together, i.e., the construction plastic in the sloped ceiling with the ventilation duct's as I described above. Finally, we put on gypsum and fiberglass fabric and painted it white. In hindsight, perhaps I should have done it differently? But is it possible to get it 100% tight everywhere? Surely there must be a limit of reasonableness somewhere - right? There ought to be someone here in the forum who has done this a few times and who can share this knowledge with us....
I will try to explain how I did it.
The chimney pipe (NVI 2000)
Through the intermediate floor, I have nothing at all, just mineral wool and at least 50mm to combustible material. Where the chimney pipe goes through the upper floor, I built a square frame around the pipe with 45x45 studs. The minimum distance is also 50mm to the pipe this time. I built the frame for two reasons: partly to have something to attach the ceiling to closest to the chimney pipe, but also to have something to attach the rubber sheet to. The rubber sheet was square with a hole in the middle that had a significantly smaller diameter than the chimney pipe, to ensure it seals properly. The outer dimensions of the rubber sheet were about 50x50cm if I remember correctly. Since I received the rubber sheet after the chimney was installed, pressure tested, and approved, I didn't want to disassemble the pipe sections to put on the sheet. So I had to cut the sheet and slide it on from the side. While I was at it with the scissors, I slightly increased the diameter to make the sheet somewhat easier to work with. We fastened the sheet against the pipe with straps and applied a generous amount of silicone to minimize the risk of leakage. That was the rubber sheet against the pipe. After this, it was time to attach it to the frame I built. There were two of us for this task since the rubber, for some reason, always wants to return to its original shape. So after a few curses, we managed to attach the rubber sheet to the stud frame in a stretched position and stapled it with a staple gun. After this, I smeared more silicone on the outside and then folded the vapor barrier over the rubber sheet and stapled it as well. I cut the vapor barrier about 50mm around the pipe, but it probably could have gone all the way forward.
Regarding the ventilation duct and the sealing between the fire mat and the sloped ceiling's vapor barrier, it was not as easy to seal and make the sealing good. It’s kind of in the nature of things that it becomes difficult to seal against the fire mat's "chicken wire." But I made it simple for myself. I took a rectangular piece of leftover construction plastic and wrapped it around the fire mat that was already on the ventilation duct. I made sure that the piece of construction plastic went a bit into the ceiling before I taped it tightly against the fire mat. Then it was just a matter of taping the vapor barriers together, i.e., the construction plastic in the sloped ceiling with the ventilation duct's as I described above. Finally, we put on gypsum and fiberglass fabric and painted it white. In hindsight, perhaps I should have done it differently? But is it possible to get it 100% tight everywhere? Surely there must be a limit of reasonableness somewhere - right? There ought to be someone here in the forum who has done this a few times and who can share this knowledge with us....
Your setup regarding the smoke pipe sounds good! I understand that a "gypsum drum" is a common solution, but it's very difficult to fit in afterward. The rubber membrane you mention might be what I'm looking for. I wonder what material it's made of that isn't flammable.
A similar rubber membrane should be able to run against the ventilation duct, right? As I understand it, one shouldn't let the regular vapor barrier go near the pipes as it can melt with heat. The whole setup with the vapor barrier would break if it's taped around this close to the duct. I hope someone else has some ideas. And just like you say, maybe you have to be lenient in some places
- or maybe that's precisely what you should NOT do. A perfectly airtight house where the air doesn't escape through incorrect paths except around the ventilation duct, which might then lead to a larger hot air flow right at this spot, which in turn means a higher moisture load at one and the same spot?
A similar rubber membrane should be able to run against the ventilation duct, right? As I understand it, one shouldn't let the regular vapor barrier go near the pipes as it can melt with heat. The whole setup with the vapor barrier would break if it's taped around this close to the duct. I hope someone else has some ideas. And just like you say, maybe you have to be lenient in some places
- or maybe that's precisely what you should NOT do. A perfectly airtight house where the air doesn't escape through incorrect paths except around the ventilation duct, which might then lead to a larger hot air flow right at this spot, which in turn means a higher moisture load at one and the same spot?