I am building a guest apartment in what used to be an unfinished loft above a garage/tool shed in a house built in the 1930s. I have a carpenter helping me with most of the technical work, but he is on vacation and I don't want to disturb him. In the walls, I have a variable vapor barrier (ISOVER Vario Xtra), but now that I am starting to lay the floor, I'm a bit confused. It seems like there are many different opinions on whether to have a barrier/blocker downwards or not, depending on whether you have a crawl space/slab/floor heating, etc.
Under the apartment, there is an uninsulated garage + tool shed. The structure between the garage and the apartment is 145 mm and constructed as follows (from below): double gypsum > insulation (145 mm) > old plank floor > 22 mm floor chipboard. I now want to lay gray card paper and oak parquet. Do I also need to put down a vapor barrier/blocker under the paper?
Thanks in advance for the response.
Under the apartment, there is an uninsulated garage + tool shed. The structure between the garage and the apartment is 145 mm and constructed as follows (from below): double gypsum > insulation (145 mm) > old plank floor > 22 mm floor chipboard. I now want to lay gray card paper and oak parquet. Do I also need to put down a vapor barrier/blocker under the paper?
Thanks in advance for the response.
The situation can be compared to a joist over a crawl space. Typically, there is no form of vapor barrier above the insulation in that case. If you were to use one, probably nothing dramatic would happen.
Thank you for the response!
I'm considering how one should reason. The barrier is there to prevent humid indoor air from seeping into the walls, meeting the cold, and condensing. Is the idea that the humid indoor air tends to rise, and therefore the floor isn't a problem?
I'm considering how one should reason. The barrier is there to prevent humid indoor air from seeping into the walls, meeting the cold, and condensing. Is the idea that the humid indoor air tends to rise, and therefore the floor isn't a problem?
Vapor barriers began to be used at the same time as mineral wool insulation, primarily because condensation reduced the insulation's efficiency. This problem was not as evident when using sawdust or wood shavings as floor insulation. While it is true that the warm air (and therefore also the most humid) in a room is at the top, this is hardly an explanation. There are situations when a moisture barrier in the floor is important. There is absolutely nothing wrong with having a vapor brake under the floorboards.