Hi, 18x40, 6ft steps, vermiculite bottom, live in PA. How long can you store a liner before installing? I would like to buy the liner now while on sale and install in the spring, will it hurt the liner if I store it in the house to sit that long? Also when installing what do you do for the opening at the stairs when fitting the liner using the shop vac to suck out all the air? Also if I have to patch the bottom what is the vermiculite to cement ratio for mixing?

Thanks, Terry