I'm dealing with a long (2 m+) waste pipe coming from a bathtub. It's currently completely unsupported and is bowing in the middle.

What's the best way of supporting its weight when full of water?

The chipboard above has tiles laid directly on top so screws will be troublesome.

long pipe


2 Answers 2


Use the joists.

I see a joist to the far side of the pipe, I assume there is one on the camera side of it too. Screw plastic or nylon straps between the joists, just taut enough to do what you want.

Or, put wood blocks between the joists above the pipe and use metal pipe hangers from the blocks.

  • An easy way to do this is to cut the cross-blocks long so they fit at roughly a 45 degree angle. Then just screw through square with the joists using 70mm screws.
    – isherwood
    Jun 1 at 13:43
  • Perfect and obvious answer, thanks. What do I need to search for to find this straps? Jun 1 at 14:08
  • "pipe strap" or "hanger strap".
    – isherwood
    Jun 1 at 14:21
  • …or just 'zip tie', if you put a brace above.
    – Tetsujin
    Jun 1 at 14:34
  • 1
    Or... put wood blocks between the joists below the pipe and let it fly lose so you don't hear it popping back and forth over a hanger or strapping when it expands and contracts from heat. Plumber should've ran it along one of the joists. Needs blocking. Strapping optional, and in some cases undesirable. Fix the tile where it meets the tub so you stop growing mold. Also, 'chipboard' w/ no sub flooring?
    – Mazura
    Jun 1 at 23:43

If unsightliness isn't an issue , I would pocket screw (i.e. drive it at an angle) a 2x2 into the board next to it. It should be close enough to pick up the load of the pipe.

  • Sorry do you mean sideways into the joist next to it? I kind assumed you didn't want to put sideways load onto but if you put a buffer bit of wood to marry it up perhaps okay? And what hardware would you use to go around the pipe? Jun 1 at 12:32
  • 1
    If you have a power screwdriver (impact driver, drill, etc.) then take a 2.5-3" screw and drive it at, say, a 45 degree angle through a short piece of 2x2 into the 2x4 next to the pipe. If you have a pocket screw jig, just add a pocket screw hole first. Avoids having to support it from the ceiling. I wouldn't do anything to the pipe itself. It shouldn't be able to roll off the 2x2 if you make the board long enough
    – Machavity
    Jun 1 at 12:35
  • Oh I see, you're just supporting it with a wooden shelf made from 2x2? Jun 1 at 12:38
  • More or less. I would assume a 2x2 sticking out every 6" or so should give it the support it needs.
    – Machavity
    Jun 1 at 12:42
  • 2
    Blocks spanning the entire cavity are a much better strategy. Cantilevered supports usually sag.
    – isherwood
    Jun 1 at 13:45

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