Question: After the scene in which the death eaters attack Harry and Ginny, everyone runs back to The Burrow which is being burnt down. My question is why does everyone look so sad? It's not like they're going to be homeless. They could have used the spell aguamenti to extinguish the flames, and any further damage could be fixed with the spell reparo. I've heard of fiendfyre in the Harry Potter series, but this just looked like normal fire to me.
kristenlouise3
19th Jan 2013
Harry Potter and the Half-Blood Prince (2009)
Answer: It should also be noted we have only seen reparo repair broken items. We've never seen it restore anything that is completely destroyed to nothing or to ashes. Given there are limitations to what magic can fix (like wands and brooms), it wouldn't surprise me if it can't bring something back that was destroyed to ashes or to nothing, especially given there are things that can incinerate very quickly even in a regular fire, such as pictures. As someone whose family went through a devastating house fire, losing pictures was one of the saddest things to lose, as you can't replace those no matter what and they are gone fast in a fire. Given we know magical limitations exist, it wouldn't surprise me if irreplaceable items in the Burrow were destroyed beyond reparo.
Answer: According to Gamp's Law of Elemental Transfiguration, you cannot create all things with magic, so some things would definitely be lost in a fire - magical or otherwise.
kristenlouise3