Land value appreciation is not part of GDP. Buildings on land typically depreciate instead of appreciate, but upgrading or remodeling are definitely GDP.
While land value appreciation (which gp cited) isn't part of GDP, rent (and imputed rent) are part of GDP, so that still flows through to GDP (at least to the extent that rent and property values are related).
Exactly, rent and loans/mortgages interests linked to the appreciation of assets are all included in the GDP.