Replacing 'sad' lawn with play area

Hi everyone, just looking for someone with experience to advise. My generally sensible husband is often a bit clueless when it comes to gardening. He's decided to replace a shabby, mossy corner of our lawn with a play area - probably 7m x 3m - as he is fed up of maintaining it (and for some reason forbids me to try).

His approach is one I don't entirely trust as it seems too easy! He simply plans to lay down a weed membrane then pour a huge amount of play-grade wood chip over the top, retaining it all with sleepers.
He expects this to last for about 5 to 8 years.

Is that going to work? I can't specifically pick fault with it, but wonder if he should be doing something more to prepare the ground.

 

Probably

I'd kill whatever is there with weedkiller first - to reduce the amount of "stuff" underneath the membrane that wants to "have a go" ... but other than that the only other problem is that Bark (or even Gravel) over weed membrane provides some anchor for weed seedlings. But they are very easy to remove (as they aren't rooted into the ground), but it gets harder the longer they are left. So keep on top of that (but it will be minutes-a-month at worst