Replacing a Rotted Floor Under the Toilet

For minor rot, a flange support is a quick fix

Minor wood rot around a toilet flange doesn’t always mean you have to replace the subfloor. Solve the problem with a metal flange support instead.

By the DIY experts of The Family Handyman Magazine

Install the flange support

If only the area directly below the flange is rotted, you can install a two-piece steel closet flange support. It goes under the flange and transfers the load of the flange and toilet (and you) out onto more solid surrounding wood. But if your floor is severely rotted, say more than an inch beyond the flange, you're stuck replacing the flooring around the toilet.

Flange supports are available at home centers and plumbing supply stores for either cast iron, plastic or brass flanges.

Back to Top

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Adjustable wrench
  • Corded drill
  • Drill bit set
  • Rags

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Metal flange support
  • Stainless Steel screws
  • Wax ring