Your other question requires a contractor and estimates, perhaps an architect as well. email@example.com is a talented & knowledgeable architect, but finding a qualified builder is important - get quotes... Hope this helped.
The appraised value is an estimate of how much a buyer would be willing to pay for the house in todays market. This is different than the replacement value which is how much it would cost to rebuild the if it were destroyed (like in a fire).
You may already know all this. Here in many parts of Brooklyn, especially in Park Slope, the market value is much higher than the actual replacement value because of the high demand for homes in the area. This holds true even in a down market.
Most people would be safe. With a $675000 replacement value estimate, in the end it also depends on how expensive your tastes are ! :)
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