Outside Peak

Family's outdoor retreat takes fun to the summit. 

By Gina Parsons

Photography by Kim Dillon


Tommy and Tara Holstein built a mountain—complete with a waterslide and a waterfall—in the back yard of their Wentzville home. “We wanted to make our back yard as fun as possible,” Tara says. “It keeps us young too.” The family loves to entertain, and wants plenty of awesome spaces to accommodate guests, including their kids, grandkids and everyone’s friends.

    When they bought the home in 2019, the only backyard feature was a small deck on the side of the house toward the driveway. The house’s lower level had no walk-outs, and the yard was bare.   

    Tommy wanted to recreate the feel of the back yard at his childhood home, which was in a rural area of northern Florissant. “Growing up, friends always wanted to hang out there,” Tommy says. You felt like the only person in world when back there. The rest of the world would melt away.”

    Since buying the house in Wentzville, they’ve added one outdoor project every year. Their back yard now has two walkouts from the lower level, a deck that wraps around the entire back of the house with stairs leading down to the back. Earlier this year they added a motorized louvre roof above the deck. “All the louvres actually open and close, which is so nice especially when you want to sit out and the sun is out,” Tara says. They’ve created a conversation area with a fire pit in the center, and a 24-by-50-foot, 45,000-gallon pool. The crowning jewel is a 17-foot mountain, complete with a waterfall, and a waterslide that drops into the 8-foot-deep end of the pool.   

    They created the mountain and the fire pit by using foam core construction. For the process, they shape the Styrofoam, then apply and hand carve several layers of concrete to the outside of the foam.

    The advantages of using foam core construction over actual rock include that it can be molded into whatever shape is desired, it’s much lighter and it’s still extremely strong, Tommy explains. “It’s a lot easier than bringing in boulders,” Tara says.

    “To build with foam core construction is significantly less disruptive because we’re carrying in bags of cementitious materials, versus hundreds of thousands of pounds of stones that would be required to replicate that same build,” Tommy adds. “If you go to the zoo or amusement parks. They don’t use large boulders, it’s all built and hand carved.”

    The Holsteins don’t stop with their own yard. Through their outdoor living company, Solid Ground, the Holsteins also transform the back yards of others, creating whatever the homeowner dreams up. “Tara and I have focused on the feeling you get from a space. What is the homeowner trying to achieve,” Tommy says. “Just building a pretty deck, or a patio or a fireplace, that’s nice, but it really is about that emotion or that feeling that we’re trying to hone in on. We’re helping them create memories.” 



Solid Ground