Hello,
We are considering insulating the interstory floor when we move into our newly purchased old 2-story townhouse since the ceiling will be replaced anyway. (today, there is barracuda-ceiling almost everywhere, brrr)
On the walls in the living room, you can see blackish discolorations on the wallpaper at the ceiling molding against the outer wall. According to the inspector we hired, this is due to cold drafts.
Is additional insulation of the interstory floor the right way to tackle the problem, and should a vapor barrier also be installed? Or should a vapor barrier only be placed against, for example, outer walls and roof beams? (i.e., against unheated spaces). In addition to improved energy efficiency, we also want to achieve better soundproofing between the floors.
I have tried to search for information on the matter but can't find the answers.
We are considering insulating the interstory floor when we move into our newly purchased old 2-story townhouse since the ceiling will be replaced anyway. (today, there is barracuda-ceiling almost everywhere, brrr)
On the walls in the living room, you can see blackish discolorations on the wallpaper at the ceiling molding against the outer wall. According to the inspector we hired, this is due to cold drafts.
Is additional insulation of the interstory floor the right way to tackle the problem, and should a vapor barrier also be installed? Or should a vapor barrier only be placed against, for example, outer walls and roof beams? (i.e., against unheated spaces). In addition to improved energy efficiency, we also want to achieve better soundproofing between the floors.
I have tried to search for information on the matter but can't find the answers.
A vapor barrier is applied only to exterior walls and roofs, not in intermediate floors.
The barrier definitely does no benefit in the intermediate floor, but it doesn't necessarily cause any harm there either. The 1 1/2 story houses that are sold with an unfinished upper floor often have an uninsulated upper floor and instead an insulated intermediate floor and thus the vapor barrier there as well. As far as I know, this vapor barrier is often left in place when the attic is later insulated and furnished, without it seeming to cause any major problems.
The barrier definitely does no benefit in the intermediate floor, but it doesn't necessarily cause any harm there either. The 1 1/2 story houses that are sold with an unfinished upper floor often have an uninsulated upper floor and instead an insulated intermediate floor and thus the vapor barrier there as well. As far as I know, this vapor barrier is often left in place when the attic is later insulated and furnished, without it seeming to cause any major problems.
Thanks Mikael 
. Any thoughts on how to deal with the draft then? Will the insulation help mitigate it?
Anyone with tips on insulation material choice?
. Any thoughts on how to deal with the draft then? Will the insulation help mitigate it?Anyone with tips on insulation material choice?
Isolation will hopefully curb the cold draft.
Cold draft is due to cold surfaces, and you might also refer to drafts as cold drafts.
So you simply need to
-get everything sufficiently insulated.
-Make everything airtight (with plastic, wind protection fabric, wind paper, or something else that stops wind and drafts).
Also, check the seals in windows. Windows create a cold surface = cold draft under the window, better windows = less cold draft.
Suggestions for insulation...
Mineral wool, i.e., roxull, paroc, isover, and whatever more the different brands are called.
At Bauhaus and Byggmax, they probably have something non-Swedish, but they still work equally well.
Watch out for the cheap roll insulation from Byggmax and Bauhaus (and possibly other places as well) that has a lambda value exceeding 0.037. It is flimsy and quite poor and clearly offers worse insulation because it has too low density.
I've used some of the cheap mat from Byggmax in some places, but would never put it where a good insulation value was important.
However, there's nothing wrong with the regular Byggmax board.
Cold draft is due to cold surfaces, and you might also refer to drafts as cold drafts.
So you simply need to
-get everything sufficiently insulated.
-Make everything airtight (with plastic, wind protection fabric, wind paper, or something else that stops wind and drafts).
Also, check the seals in windows. Windows create a cold surface = cold draft under the window, better windows = less cold draft.
Suggestions for insulation...
Mineral wool, i.e., roxull, paroc, isover, and whatever more the different brands are called.
At Bauhaus and Byggmax, they probably have something non-Swedish, but they still work equally well.
Watch out for the cheap roll insulation from Byggmax and Bauhaus (and possibly other places as well) that has a lambda value exceeding 0.037. It is flimsy and quite poor and clearly offers worse insulation because it has too low density.
I've used some of the cheap mat from Byggmax in some places, but would never put it where a good insulation value was important.
However, there's nothing wrong with the regular Byggmax board.