14/08/2014 12:51 BST | Updated 22/05/2015 06:12 BST

The Reluctant House Dad: Why Is My Tweenage Daughter So Incredibly Messy?

I have the most perfect 11-year-old stepdaughter. Bright, funny, charming, beautiful, kind, caring, confident, popular. Perfect in every way. Except one. She is the messiest, most untidy, bordering on slovenly, person I have ever met in my life.

It is THE only issue (so far) that causes conflict between us and it's pushing me dangerously towards the end of my wits.

It's not just her bedroom (which could easily feature in one of those documentaries about hoarders), it's her absent-minded dedication to leaving a never-ending trail of rubbish, and litter, and filthy clothes in her wake.

No matter how much I nag, nor cajole, nor motivate with promises of untold rewards or threats of yet-to-be-conceived punishments, nothing ever – ever – gets through to her Tweenage brain to PICK UP THAT CRISP PACKET, PUT THAT BANANA SKIN IN THE BIN, PUT YOUR WORN PANTS IN THE WASHING BASKET, LOAD YOUR DIRTY PLATE IN THE DISHWASHER – AND STOP, JUST STOP, PLEASE, FOR MY SANITY'S SAKE STOP, DUMPING YOUR P.E. KIT IN THE MIDDLE OF THE LIVING ROOM AND THEN WALKING AWAY FROM IT.

OK, it's only mess. It won't kill anyone. And once it's cleaned up, it will get dirty again, so what's the point tidying in the first place? And with different DNA in my body, I could perhaps have sympathy with that point.

But I'm a house dad. I both live and work at home. It is both my office and my prison. I have no escape from it. And therefore, I prefer, nay demand, that it is in a certain state of order and cleanliness so that I don't feel I'm existing on a council tip.

As a result, I have spent a lot of the last couple of years tidying aka maintaining a status quo of sanitary sanity. I pick up cups and clothes and empty packets and pieces of this, that and lots of the other.

But I don't want to do it any more. I can just about forgive my eight-and-five-year-old sons for their debris dropping – for theirs is nothing to compare with their big sister's and it is high time she led by example.

When I've quizzed her on this, gently, not menacingly, over a cup of hot chocolate, she doesn't deny her messy ways, but mounts the defence of: "If you think I'm bad, you should see my friends' bedrooms – they're even WORSE than mine!"

Which makes me shudder to think!

But after some pleading on bended knee, she always promises to be more considerate – and then always fails.

What's that about? Perhaps she genuinely can't see the trail of devastation she moults like a Labrador's coat? Perhaps her head is so filled with other more interesting stuff (like handbags and scarves bearing moustahce motifs) that her brain doesn't computer untidiness? I turned to the trusty t'internet for advice and found some interesting theories as to why 'Tweenage and Teenage Girls Never Clean Their Rooms'.

Reason Number 1: "Too much stuff, not enough stuff-holders Teenage girls like to buy things," goes the theory.

No arguments there. Over the last year, my stepdaughter has gone from a shrugger at all things consumerist to an avid shopaholic. But there simply isn't enough storage space in her room to accommodate it all.

So, here's a tip: "Buy your daughter some more storage units. A chest of drawers, a book shelf, even an extra crate or end table. If her stuff has a designated home, the stuff is less likely to end up in a pile on the headboard of the bed."

Reason 2: Ownership. "When teenagers live in their parents' house, there isn't much that truly belongs to them. Parents often use this fact to their advantage: 'As long as you live in my house, you follow my rules!' 'When YOU pay the mortgage, YOU can do whatever YOU want!'

"But a girl's room is not just a dumping room for her stuff. It's the one place in the house that she can be herself, that she can relax and not have to worry about following other people's rules. Her messy room is an outpouring of her personality and of her busy life. It's where she doesn't have to pretend to be neat if she's not."

Reason Number 3: Different priorities. "While parents may put cleanliness and orderliness near the top of their priority lists, (most) teenage girls do not. And it's really hard to get a girl (or anyone!) to do something when she feels like she has more important things to get done. Like homework. Or play rehearsal. Or tennis practice. Or shopping. Or sleeping. No one wants to feel like she is wasting her time."

Reason Number 4: Futility. "If it's hard to do something that isn't high on the priority list, it's even harder to do something when you know it's a pointless effort. We know that our rooms are going to get messy again, probably very soon, so it's quite difficult to force ourselves to clean them. Why do something if you're just going to have to repeat yourself a week or a month later?"

Well, they all sound like sound enough excuses, sorry, reasons! But regardless of the reasons, I've decided I won't be treated as her sweeper-upper slave any longer. So what can I do about it?

According to Dr Robert Epstein, author of 'TEEN 2.0: Saving Our Children and Families from the Torment of Adolescence': "Get to the root of the problem Sometimes it's just an inability to purge memorabilia or a simple case of laziness.

"However, if your teen's goals, commitments or grades are suffering due to his mess, then it's time to insist on change. "Chances are he may need help, but it's important for her to take ownership of this overhaul. Help her realise that the mess is making things more difficult for her.

"Many young people don't know where to begin, and their tendency to be impulsive doesn't help either. Set realistic expectations – and don't expect that she won't have setbacks or need reminders.

"The initial clean up should be done in stages. He can start with the floor; then move to the closet on another day. If the task is in manageable pieces, it will be less daunting.

"So be a great role model. Show them how to do it. Sometimes it's helpful to take them shopping for organizational aids, such as storage cubes or shelves.

"Always watch for any signs, even small signs, of neatness – and praise and reward like crazy."

All of this is great advice that I'll follow, but if it doesn't work, I've got another solution up my sleeve. When my stepdaughter starts secondary school in September, we're going to stay giving her pocket money. But she's going to have to earn it – by working in lieu for it.

Thus, she will be given an allowance of £10 a month – but for every stray pair of tights, discarded apple core or dumped school bag, she will be docked 50p ahead of payday.

I've a feeling our shopaholic Tween is soon to become Little Miss Tidy.