Paul Beaulieu works on the new tree house he is building for his 9-year-old daughter, Kali, 9, and 6-year-old son, Justin, not pictured, at their house on Niskayuna Street in Auburn on Sunday afternoon. “The kids have been asking for a tree house for quite a while,” said their mother Shannon. “Once they are done, mom gets to decorate it,” said Shannon Beaulieu. “I keep telling them to keep their feet clean,” said Shannon. “The roof was the hardest part,” said Paul, who started the project three weeks ago.