Air gap behind liner

[PhantomAndy]

Most builders size the liner so that it will have a tight fit (meaning that it will have to stretch to truly fit all the walls and corners).

It will take some time for it to get it's final fit, but you will be fine. Undersizing the liner a little helps to prevent wrinkles during the liner installation and is a normal practice.

[tonyl]

I'm with Andy...having just replaced our liner....

During filling I wondered if the corners would EVER fit.... they absolutely did, so never underestimate the power of wate pressure.

Had some anxieties during filling...even halfway up the walls, I had corners hanging out 6"or more, they are now now maybe 1/2" away, AT THE MOST.

Now that it's filled, we couldn't be more pleased with the fit. No wrinkles and the liner stays in the bead throughtout.

Better to have a tight fit when it comes to liners.

Hope this helps, Tony