I've been a PHP developer for about 6 years now - the last two years I have been pretty inactive though. Just recently though, I have been reading resources on all the different programming patterns (Factory, Singleton, Registry, Observer, MVC, etc) to try and get my head around good programming techniques.

For myself though I find that I can only truly understand how these methods work when I am forced to do them myself.

I have a large project I am doing at my workplace (me only) that involves building a very complex PHP application.

I would like to know your professional opinion; should I spend the extra time to program this PHP application myself and really, properly learn all these different programming patterns? Or, should I just build on top of a PHP framework like the Zend Framework for speed's sake (and flexibility/features)?

I have found understanding exactly how the Zend Framework works hard, just because I haven't been exposed to using these programming patterns myself. I hate that - I want to fully understand exactly what is happening in my application and know exactly how each part relates to others.

Thanks in advance!

If I was in your shoes I would use the Zend framework. You can use it without knowing all gory details but you have access to them anytime. So you can understand how it works whenever you have time to spend on that. When designing your own classes that reflect business logic the programming templates will be useful anyway.
I think you are better off in the long run if you get used to a common framework.
(Myself I was working with PHP about 5 years then had to switch mod_perl, then to Java. So I don't have more experience than you but I heard from more experienced colleagues that zend framework was their favourite choice...)

Thanks for the advice j-ray.

I think I will go with the Zend Framework. I've been using it on and off for a couple of years and have found it to be really good.

I am also starting up a project at home that I will code myself - framework and all - purely to help me understand all the different patterns by having to write them.