Calculating the time for a pressure change

[Sam1010]

I've been searching and it seems I am not smart enough to find the solution for this...

Let say I have a fully closed box made of concrete left in air. The pressure inside the box is 0.01atm. Since it is left in air, the air will come inside the box through concrete walls(since concrete is porous) and the pressure inside the box will go up to 1atm eventually(same as outside pressure).

If I have the permeability coefficient of the concrete and the dimensions for the box, how can i calculate the time required for the inside of the box pressure to go up to 1 atm from (0.01 atm)?

 

[BvU]

Hello Sam, $\qquad$ $\qquad$!

This looks a lot like an exercise or homework, and at PF that means an effort from your side is required:
What is the meaning of a permeability coefficient in this context ?