So, I have a car I value at ten grand. But it turns out I only get five grand for it when I sell it. That's a five grand loss (clearly). I then buy a new car, paying ten grand for it. Total cost of that car: 15 grand.
If, on the other hand, I value my car at minus five grand, get five grand for it, and buy a new one for ten grand – well! The new car is – actually – free.
No it's like a house, your house is destroyed by a earthquake, you buy another house, you 'lost' the value of your old house and spent the value of your current house.