How big a space does a 'Prairiefire' crabapple need?

I have a space that is 18 feet from the building to the sidewalk and at least twice that wide, and was thinking of planting a 'Prairiefire' crabapple there. Is that enough space for the roots? More specifically, will the roots damage the concrete sidewalk or the foundation of the building?

They're not known to disturb pavement. At maturity they get to about 15 x 15, although I've seen one, grown in ideal conditions, nearly 20 x 20. They like, but don't need, acid soil. They will adapt to a wide variety of soils. This is a disese resistant cultivar used in municipal street tree plantings. The fruit persists into winter and is attractive.

http://davesgarden.com/guides/pf/go/74858/

Crabapples, like most any other tree, will form woody roots that increase in diameter over time. If there is hospitable rooting zone beneath pavement, they will grow there, increase in diameter, and eventually lift pavement. There are many examples of just this condition around Louisville KY, but it will take longer the farther away from pavement that you plant the tree. More vigorous and rapidly growing trees generally will have roots that increase in diameter more quickly. There are standard size crabapples (that are about 15 years in place) heaving pavement and pavers in the Old Louisville neighborhood near Central Park in Louisville.

Standard size crabapples (of which 'Prairifire' is one) will reach a mature size of 20' x 20' and really only need normal conditions, not optimal, to reach this size. The pictures I contributed to PlantFiles (linked above) are in the 25-30' range of spread, and have had no particular extra care since they were established nearly 30 years ago. The Bernheim collection of crabapples, in fact, is one of the best places in the midwest to see and evaluate a lot of Malus simply because they were not pampered, but allowed to grow under the conditions of soil and climate found there.

The space suggested in the original post will support a crabapple for quite a long time (9' to building and 9' to sidewalk). I doubt that the building foundation is any jeopardy, but the sidewalk might be. Plan to prune off branches that are growing toward the sidewalk so that you allow for pedestrians to use that facility without ducking or being poked in the eye. If the sidewalk is of recent standard municipal construction, it should be fine. If it is older and/or without much compacted aggregate base under it, you may eventually need to deal with upheaval.

There probably aren't many/any other trees that would tolerate this type of planting site that I would recommend instead. You should be able to grow a crabapple there for 15+ years or more before any of your worries may become an issue. That's not bad for an urban situation.

snapple45 and ViburnumValley - Thanks for your input! Very helpful!