[picture shows the back of a PAX wardrobe that has been glued, nailed and screwed ensuring that it will never come off - this is the BEST PAX HACK that you can do to ensure the integrity and longevity of your new closets]
Chapter 1 - PAX Hacks and 'Peak Furnishings'.
If you have been to IKEA then like me you likely have a slight fetish for well organized and functional closets - PAX. I will not be writing about the DESIGN aspect of those closets - you know exactly what you like and how you want things to look.
The PAX system, in my opinion, is a great example of the phenomenon of 'peak furnishings' - meaning there exists a closet, which when properly designed, installed and hacked [hacked, well, because it is an IKEA product] will produce satisfactory results in 99% of the cases. AND it will last well beyond the 10 years that IKEA provides warranty for. I have been installing PAX the traditional way - free standing - or more popular, building them in, for I say 10 years, including calls to 'fix, adjust, and re-install'. And over the course of those ten years I have noticed similar challenges coming up. Two important points to remember - the PAX system is designed to be manufactured in centralized location [the efficiency reduces the cost] and then distributed; it is meant to be assembled by the end user [the actual design of the box has to be accessible to average DIY-selfer].
Why would you want to go through the process that I will outline below? I see two reasons:
A] You want to extend the life of the PAX - traditionally installed PAX [as per IKEA instructions] will last you about 10 years. Beyond that, the use of it will become cumbersome and challenging - it may start bothering you when the doors will rub against each other; the pull out drawer/tray/hanger mechanism may become annoying; shelves will sag and back may become loose OR worse come off completely; the entire box may lose its rigidity and feel 'wobbly' [that's how my customers describe the well worn out PAX box]. You may end up thinking, 'Hey! I did everything right, I followed the instructions, this is the end and I need to replace my closets.' And this point I want to stop you and say 'Wait! Before you discard that PAX, if you follow my instructions, you can breathe another 10 YEARS OF USE into that box! SAVINGS!
B] You want to build-in that box to make it look fancy. PAX boxes are fairly plain - they have a great selection of affordable styles of doors - both hinged and sliding - BUT that box is just SO PLAIN! As a conscious shopper, seeking good value for your hard earned dollar you want to take advantage of the affordable functionality and skip the 'custom closet route', which I assure you, is very expensive! You want to give your closets personality and flair - you want some side panels, you want some bottom trim to cover that little kick, you want a crown moulding that matches your house decor. SO, if you are going to go through all the trouble of fabricating all the custom pieces you might as well make it last. MORE - another important point to remember is the fact that when you built-in things [at least when I do] - they become PERMANENT. That is precisely the reason why I go through all hacking of the PAX that I work on - that closet is built-in and DONE. You will not be able to pull that box off the wall to fix a loose back; if that top is sagging and pulling in the doors [so they rub against each other] - there will not be an easy fix to straighten it out. The FIRST STEP in building in the PAX, is addressing all the issues/challenges that will arise during the lifespan of the closet - once those are addressed, your closet will function well YEARS beyond that 10 year mark.
Chapter 3 - Are you ready? Boring technical stuff... that you need to know.
PAX gables are super light. That is not a sign of any deficiency - opposite, that is a sign of high-end design. That vertical is a high-end sandwich - torsion box - designed to be light weight and perform as intended - the joinery on the box is strong, it will resist bending and twisting AND it will allow for great many hardware changeovers that you may desire over the lifespan of the closet. There are no benefits of using a solid core panels....unless you want you closet to be heavier.... but that never really enters into the closet equation. I've never heard anyone brag about 'how heavy their closets' are, BUT, I did hear people bragging about how functional their closets were!
Chapter 2 - The BOX