A below-grade full bathroom addition in Seattle, WA, featuring shower relocation, multi-layer waterproofing, custom tile work, recessed lighting, and complete fixture installation.
This basement bathroom project in Seattle required coordinating four trades in sequence, rough plumbing, waterproofing, tile, and electrical, before any finish materials could go in. Seattle’s wet climate and older housing stock make below-grade moisture management especially critical, so waterproofing was treated as the foundation of the entire scope, not a finish-phase add-on. Customer finish selections, including tile, fixtures, and vanity, should be confirmed before the waterproofing and tile phases begin to avoid scheduling gaps.
The shower was relocated to a new position in the floor plan, which required adjusting the hot and cold supply lines, moving the drain, and re-routing waste lines to meet the updated floor plan. Stop valves in both the bathroom and the adjacent laundry room were replaced at the same time. Full bathroom enclosure framing was also completed at this stage, including partition walls, ceiling soffit, and a dedicated furnace closet separation. All framing is built plumb, level, and compliant with the Seattle Residential Code.
Waterproofing was installed as a system. That means a liquid membrane on all wet-area surfaces, a sealed shower pan liner, waterproof cement backer board, and anti-mold treatment before any tile is set. Every seam is taped per manufacturer spec. In a Seattle basement where ground saturation and humidity run high year-round, epoxy grout on all wet surfaces is standard practice, not an upgrade. Cement grout in a below-grade shower is a long-term moisture problem waiting to happen.
Tile installation covers the shower walls, shower pan, built-in niche, and main bathroom floor. The pan was set to a minimum 1/4-inch-per-foot slope toward the drain. Epoxy grout is used throughout all wet surfaces, with sealant applied on the pan. Metal edging was applied at all exposed tile transitions.
GFCI-protected outlets are installed per code, along with recessed LED lighting wired as part of the overall basement lighting plan. Non-tiled wall and ceiling surfaces received moisture-resistant drywall, taped, mudded, and textured to match the rest of the finished basement. Final fixture installation includes the bathtub or shower base, vanity, toilet, faucet set, showerhead, and valve trim. All supply lines, wax ring, drain covers, and caulking are included.
Project type
Basement Remodeling
Timeline
3-5 weeks
Budget range
$80,000 – $120,000
Trades Involved
Plumbing, Tile, Electrical, Framing, Drywall
Location
We handle basement bathroom additions across Seattle and the greater King County area. From rough-in to final fixture, fully permitted to Seattle Residential Code.
