Shower Drains - Danger Of Using New Top Flange With Old Bottom Flange
Remodeling or building a new shower can be a risky job. Most showers are exposed to more moisture than the roof of the home. You want to make sure everything is done correctly to avoid any costly repairs down the road because of a leaky shower. We have learned over the years of doing thousands of shower pans that the drain is the most leak prone area. The most common reason for a leak around the drain is because the old drain is not completely switched out. We highly encourage the installation of a complete new drain; that is the top and bottom flange of the drain assembly.
When the shower sits on slab concrete it can be cumbersome and costly to switch out the entire drain set because it may involve breaking up the surrounding concrete. This added cost can make it tempting to only switch the top half of the drain. This is not recommended. Often the top half and its bolts are not an exact match for the old bottom flange. The threading and/or the bolt holes can be slightly off. This can prevent a tight seal between the top and bottom drain flanges cause a leak when water backs up. This is why we HIGHLY recommend the installation of a new complete drain set.