Overcoming Below-Grade Issues When Installing a Basement Bathroom

By Matt Weber, Photos By Hal Jones

Creative thinking combined with innovate building products give rise to a beautiful basement bathroom.

Hal Jones, online media director of the Extreme How-To, was adding a new bathroom in the partially finished basement of his family’s lake house. Working in his favor was the fact that the unfinished space gave him a fresh canvas on which to install the bathroom amenities. However, working against him was limited square footage because the adjacent areas had already been partitioned into finished rooms. Plus, the area of construction was located on a solid concrete slab, with no drain system in place. Here’s how Hal employed traditional techniques, state-of-the-art fixtures and new DIY-friendly materials to conquer those obstacles and create a bathroom to brag about.

Fixture Fix-Up

The plumbing fixtures provide the function and focal points of a bathroom, and Hal chose Kohler fixtures to outfit the project. Kohler’s Revival Series white, porcelain pedestal-style sink provided a sleek look while economizing space. Kohler’s matching Revival Top-Trip high-efficiency toilet featured two interesting top-of-the-line attributes, a bidet (AKA dog water fountain) and an electronically heated seat, making this water closet top contender for “Most Lavish Toilet in Winston County, Alabama.” The bathtub was Kohler’s triangular Cornerstone Whirlpool Bath complete with soothing water jets and comfortable armrests to relax in a spa-like atmosphere. Hal was definitely making the most of this project.

Ever seen a bidet in action?

The supply valve beneath the toilet tank has a T-fitting to provide the bidet feature.

Drain Platforms. The first order of business for the plumbing fixtures was to determine a game plan for addressing the lack of drain plumbing. The solution: Raise the fixtures. Rather than cut into the concrete with a slab saw or jackhammer to make clearance for drain lines, Hal took an alternative approach. He constructed joisted a plywood platform for the toilet, similar to building a miniature deck, which elevated it several inches off the floor and provided just enough space to install the necessary drain lines. The toilet was then installed as usual with a flange and wax ring atop the platform. Hal also built a platform and knee-wall that encased the bathtub drain lines, which were also routed above the slab. Naturally, the fixture platforms reduce headspace when someone is standing on top of them, but Hal decided it was a logical compromise for easier installation on this project.

The toilet was installed atop the platform as usual. Shown here, Hal Jones is drilling the platform for the toilet drain.

For this bathroom, elevated platforms were constructed beneath the tub and toilet to provide clearance for drain lines. The platforms were leveled with shims as needed.