Market value is right, but I'd say it's not the value of the house that matters - it's the cost of restoring it to its original state. Cleaning up a footprint takes a few minutes; you could hire someone to do it for well under $100. Rebuilding a house takes months of effort and tons of material; it'll cost you tens of thousands of dollars to restore it, plus the cost of renting another home in the meantime. Those are the damages.
The cost to restore even very cheap items to their original state can be exorbitant. And in some cases, even if you restore something to its original state, additional harm is still done (like the cost of renting another home in the meantime). You have to sum all the actual damages fairly attributable to the act. It's actually not as simple as "cost to restore" or "market value".
There are also lots of cases where figuring out if damages are "fairly attributable" to a wrongful act can be tricky. For example, a doctor mistakenly tells a patient a certain type of harm cannot happen from a procedure she is considering. She has the procedure and suffers that harm. Assume it is agreed that she would have had the procedure anyway. If she suffers the harm, is it fairly attributable to the doctor's erroneous statement?
Or suppose a railroad negligently sends a person to the wrong destination. They apologize and put them up in a hotel overnight to send them to where they were supposed to go the next day. If the hotel catches on fire and their property is damaged, is that harm fairly attributable to the railroad's negligence?
It's remarkably subtle and you can find lots of examples where it's tricky to determine. That's what courts are for.