Wood wool vapor barrier mandatory or not?

[moby25]

Bonjour à tous

I had parts of cold walls in my attic.
The day before yesterday I decided to delve to see what it is.

A strip of insulation was missing behind the ba13.

So I filled this strip of 30 * 90 with wood wool that I had left.
By cons I did not put a vapor barrier.

My configuration is from the inside to the outside

BA13
Insulators
Tile battens

I don't have a rain screen or under-roof screen.
In my config, is it mandatory? because in my opinion the wool can "breathe" since there is no screen under the roof.

[aerialcastor]

The insulation should not touch the battens. Wood being less breathable than wood wool there will be condensation. If there is a small air gap no problem.

The vapor barrier is not only used to solve condensation problems, it also serves to ensure air tightness

[moby25]

wood wool does not touch the battens, however it touches a chevron on the sides

[minguinhirigue]

In your configuration, as long as the tiles are intact, no risk but if your wool is not treated against humidity (emulsion of paraffin or bitumen), the slightest leak can create mold.

By cons, as is, I do not think you need a vapor barrier (inside). But after the possible addition of a rain cover (outside) during repair of the tiles, that can change ...

[Obamot]

It's always the same. We answer without knowing the house in question, its location, etc. Answer to be taken with tweezers since the questions are made with a ladle.