Hi!
I need some help with a vapor barrier...
Background information:
I am in the process of replacing all the ceilings in our stone house built in 1960. "Above the ceiling" consists of rough boards, roofing felt, and then wood shavings insulation in the attic, and under this, we are going to install wood paneling and plasterboard.
Questions:
1. We should have a vapor barrier towards the attic, right? I plan to add more insulation later this year, but I have to wait until the radon mitigation is done (mechanical ventilation).
2. In some places, we will lower the ceiling with framing. On which side of the framing should the plastic be placed? Towards the attic or towards the room?
3. When you put up the plastic, it inevitably gets holes from staples or screws. Should you seal it in some other way there?
4. We are going to install spotlights in the hallway ceiling, cutting openings in the attic so that we don't have to lower the ceiling too much. How should you handle the plastic around the openings?
Grateful for answers!
/Elin
I need some help with a vapor barrier...
Background information:
I am in the process of replacing all the ceilings in our stone house built in 1960. "Above the ceiling" consists of rough boards, roofing felt, and then wood shavings insulation in the attic, and under this, we are going to install wood paneling and plasterboard.
Questions:
1. We should have a vapor barrier towards the attic, right? I plan to add more insulation later this year, but I have to wait until the radon mitigation is done (mechanical ventilation).
2. In some places, we will lower the ceiling with framing. On which side of the framing should the plastic be placed? Towards the attic or towards the room?
3. When you put up the plastic, it inevitably gets holes from staples or screws. Should you seal it in some other way there?
4. We are going to install spotlights in the hallway ceiling, cutting openings in the attic so that we don't have to lower the ceiling too much. How should you handle the plastic around the openings?
Grateful for answers!
/Elin
Simple basic rule. Warm air holds more moisture than cold. When warm air meets cold air, moisture is released from the warm air. Example: Warm air travels through a metal pipe outdoors, resulting in condensation inside the pipe (like a car exhaust pipe, which is why you might see water dripping from it sometimes).
Similarly, you get condensation on the outside of a glass with ice water. The moisture in the warm room condenses on the cold glass.
1. Yes!
2. The plastic should be as close to the lower floor as possible, directly above the ceiling covering.
3. You don't need to be overly meticulous. Small holes are not a problem in these contexts.
4. Tape the plastic to the cups.
/CC
Similarly, you get condensation on the outside of a glass with ice water. The moisture in the warm room condenses on the cold glass.
1. Yes!
2. The plastic should be as close to the lower floor as possible, directly above the ceiling covering.
3. You don't need to be overly meticulous. Small holes are not a problem in these contexts.
4. Tape the plastic to the cups.
/CC
kloka_elin and chris47. Here are some comments and more responses.
1: It is absolutely correct that there should be a diffspärr.
2: And it is also absolutely correct that the plastic should be as close to the inner panel as possible. It is fine to place the plastic under any glespanel, allowing you to run electrical conduits, etc., without making holes in the plastic.
3: Here, I don't quite agree. One should be very careful with the plastic and make sure that overlaps have a proper overlap and that the overlaps are clamped between the truss and the stud. There is no reason to tape, as there is no tape where the adhesive is age-resistant, so it doesn't do any good after a number of years anyway.
4: Try to get the plastic to go over the kopp, so there are no holes. Even small holes allow warm, moist indoor air to rise into the attic and can then condense, making the construction a risk factor.
5: You haven't asked this question, so I'm doing it for you. How should the ventilation be arranged? When the conditions of the house change and it is additionally insulated, etc., the demands for functional ventilation increase. Simply put, we can say that you should have negative pressure on all floors of the residence and a very slight positive pressure in the attic. There are several aspects to consider in achieving this, but with a little more information about the house, I'm happy to help. Write here on the forum, and the answers might come.
Tartan
1: It is absolutely correct that there should be a diffspärr.
2: And it is also absolutely correct that the plastic should be as close to the inner panel as possible. It is fine to place the plastic under any glespanel, allowing you to run electrical conduits, etc., without making holes in the plastic.
3: Here, I don't quite agree. One should be very careful with the plastic and make sure that overlaps have a proper overlap and that the overlaps are clamped between the truss and the stud. There is no reason to tape, as there is no tape where the adhesive is age-resistant, so it doesn't do any good after a number of years anyway.
4: Try to get the plastic to go over the kopp, so there are no holes. Even small holes allow warm, moist indoor air to rise into the attic and can then condense, making the construction a risk factor.
5: You haven't asked this question, so I'm doing it for you. How should the ventilation be arranged? When the conditions of the house change and it is additionally insulated, etc., the demands for functional ventilation increase. Simply put, we can say that you should have negative pressure on all floors of the residence and a very slight positive pressure in the attic. There are several aspects to consider in achieving this, but with a little more information about the house, I'm happy to help. Write here on the forum, and the answers might come.
Tartan
I would like a little clarification on question 3!
If you first have 95mm insulation in the wall, add a vapor barrier, and then attach 45x45 mm studs horizontally for additional insulation + the possibility to run electrical wiring, etc. When mounting the 45x45 studs, the vapor barrier is punctured. Does this need to be sealed, or can you get away with it since there is wood on both sides and the hole that results when nailing?
//Klas
If you first have 95mm insulation in the wall, add a vapor barrier, and then attach 45x45 mm studs horizontally for additional insulation + the possibility to run electrical wiring, etc. When mounting the 45x45 studs, the vapor barrier is punctured. Does this need to be sealed, or can you get away with it since there is wood on both sides and the hole that results when nailing?
//Klas
Thank you for the answers!
However, I don't quite understand how the following should be done practically:
1 drill holes in the roof deck
2 attach the cups upstairs in the attic
3 run VP pipes and electricity (on the room side of the ceiling)
4 install battens
5 install a vapor barrier
6 install drywall and mount spotlights?
How then can I get the plastic to go over the cups??
As for the ventilation, it will probably be a supply/exhaust system with air supply in some rooms and extraction in the kitchen and bathroom. Then a heat exchanger in the attic between the systems. The installation guy said that you aim for a slight negative pressure in the house itself, but he didn't say anything about the attic.
/Elin
However, I don't quite understand how the following should be done practically:
I musttartan said:
1 drill holes in the roof deck
2 attach the cups upstairs in the attic
3 run VP pipes and electricity (on the room side of the ceiling)
4 install battens
5 install a vapor barrier
6 install drywall and mount spotlights?
How then can I get the plastic to go over the cups??
As for the ventilation, it will probably be a supply/exhaust system with air supply in some rooms and extraction in the kitchen and bathroom. Then a heat exchanger in the attic between the systems. The installation guy said that you aim for a slight negative pressure in the house itself, but he didn't say anything about the attic.
/Elin
Am I blind/have a poor screen resolution/being blinded by the dazzling white snow outside?? All options are possible, but I don't see any plastic over the jars. Have you taped it around the buckets?
/Elin
/Elin