It might just be me, but I find whenever I take on a DIY project I become so engrossed in the job at hand any of my Health and Safety or Manual Handling techniques go completely out the window. (Usually we me following quite literally behind it!)
Tackling the Health and Safety aspect, doing minor DIY jobs with both my boys around ensure I stay on the safer side of things, without them has seen me demolish walls and ceilings in the house with minimal protection and in one case a massive 9 inch nail in bedded in some two by four swinging around and impaling me in the stomach. I did soldier on, it in fact gave me some of that old Viking rage, which meant I leveled the place in about 2 minutes flat!
So what about manual handing how can you ensure your not going to do yourself a mischief? I once had to move solid stone blocks that had been left out after we had a chimney stack removed, I did this by hand and afterwards I felt burning pain in my back! Thinking about it, if I had been in the workplace I would have insisted in purchasing equipment to make the job at hand safe and easy, something like a sack truck or platform truck would have made the job effortless!
Knowing how much work is still left to do in the house, two chimneys to remove and loads of rooms needing plastering having a truck in my DIY arsenal will be an investment well spent! So I will have more time for the exciting jobs like painting and laying the flooring. I am fairly certain the Mrs will have something to say about this, as when I over did it with moving the stones around I had to take to the couch living her to look after both the little monsters on her own!