How to Price Outdoor Space (Deck, Balcony, Garden) and Basements

Outdoor space is calculated in different ways, depending on the type of space you're discussing. In my opinion, I believe that terraces you can look out on to from inside your unit are far more desirable than roof terraces you have to walk up a flight of stairs to access. I don't think there's a huge difference between a garden vs. a terrace, as that is purely a matter of choice - some people really like enclosed gardens where you dig down into the earth and plant large or very permanent greenery, while others love terraces higher up where your view (hopefully) is open sky and unobstructed.

In general a wrap terrace of decent square footage (read: useful - not four foot deep by 30 feet wide juliet balconies), perhaps 200 square feet minimum (something like 8 x 25 feet) is a good basic starter terrace. A medium sized terrace to me is something like 10 x 35 feet. Really generous terraces (over 500 square feet and well laid out) that wrap a unit are most desirable.

My calculations for a wrap terrace of this type are to take comp calculations of the price per interior square foot and muliply by a factor of .2 (20%) to .5 (50%) to arrive at the price per square foot the terrace is worth. Things like how high you are, the light, the views, the layout, how well planted and structured, the flow from inside to outside, the noise level, the quality of the unit and the building itself, location, privacy, etc. all contribute to being on the high end or low end of the 20%-50% multiplier.

As to basement value, I have absolutely no clue.

I agree with poster #2's range of 20% - 50% of the indoor per square foot price depending on the factors mentioned, maybe leaning toward the lower end. I bought a co-op on the UWS with a 200 sq ft terrace that is structured and planted relatively well, and the terrance was appraised at 50K as an adjustment to non-terraced comps. It is a private terrace with an ok view on the second floor of a duplex. No idea on basements, either.

pseudonym/unnamed - thanks for the feedback. I've dug up similar benchmarks from past posts, and there's consistency around the 20-50% range.

Thanks for the info pseudonym and unnamed posters. Helpful info!