Right felt for terrace against concrete wall?

[cleverton]

Hello,

We are building a deck that is attached to the house wall, which is made of concrete elements with insulation. The builders have used this underlay:

https://bmisverige.se/produkter/und...ffusionstät,på ovansidan och sandad undersida.

Seems sturdy, but I became a bit nervous since one side is sanded and the other is a weldable diffusion-tight top side:

"YEP Plåtrems is aging-resistant and diffusion-tight,
with a vapor transmission resistance Zv 4000x103 s/m
(Sd 100m).
The product has a tear-resistant core of polyester felt that
is impregnated and coated with asphalt with added
polymers (SBS). The top side is coated
with a weldable film and the underside is sanded."

If OK, which side should face the concrete, or does it matter?

 

[surris]

I had driven the sanded side against the concrete.

 

[cleverton]

Seems like there's a mix here, in some places sanded towards concrete, in others the "plastic" side.
Do you think it's a problem?
It can probably still be fixed but will probably take a few hours of work...