I might (just might) disagree with my esteemed colleage, Helen, BUT ONLY on the "one time" issue. My position focuses on your INTENT - if your intention was to go into business then it belongs on a business return but if your intention was investment oriented then it might fly on Schedule D - MY emphasis is on might.
I also have some concern on your use of "WE". Unless you're in a community property state AND in business with your wife, the business activity likely does NOT belong on a Schedule C, but rather Form 1065 - if you were a defacto partnership - or a corporate return - if you incorporated.
Helen is quite correct though in her reference to IRC Sec. 263A costs. These are intricate and will most certainly require the help of pro.
You may also have to consider a different method of accounting besides cash. In the construction industry Completed Contract or Percent of Completed Contract are commonly used. In any case you need to consider matching your income with your revenue - the vast majority of my contructions clients accumulate construction costs as WIP (sort of like inventory) and then deduct the costs in the year of sale (or closing).
You really do need professional help.