Soil pipe through / over joists?

[Tommy Gilchrist]

When you need to start with "I know this is probably a stupid question but..." you probably already know the answer.

I need to install a new bathroom upstairs which, due to a builder letting us down, I'm going to have to plumb myself although I am going to get a plumber in to QA the work before running water.

One question. I'm sticking the toliet beside an external wall with easy access to an existing soil pipe. However the joists in the floor run parallel to the external wall and there's one tight against the wall.

I assume this means the soil pipe will have to go through the wall above the floor level? Will the smaller waste pipes i.e. from the bath and basin be able to go through the joists - they're about 200mm deep.

thanks

tommy

[John Rumm]

Your toilet probably has a horizontal outlet anyway - designed to be taken straight through the wall at a height of about 190mm above the finished floor level.

The other pipes are probably simpler taken out above floor level as well. Typically you should not make hole through joists that are more than 10% of their total depth, although close to a wall, or in cases where the joist span is relatively short you can.

[Christian McArdle]

That is the normal method of installation. To make the hole, ensure that you hire a quality SDS drill with suitably sized diamond tipped core drill. This will make a nice clean hole for you.

Christian.

[Kalico]

Take any waste pipes (inc soil) above the joists. Water pipes can go below.

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[Tommy Gilchrist]

Thanks for the feedback - the advice makes sense but do the waste pipes for the bath and the shower (only doing the bath at this stage) not need to be below the level of the plug hole?

Would this not mean you would have to raise the level of the plug hole or are they far enough above ground level anyway?

In case you haven't guessed I'm no expert on plumbing and wouldn't be at this at all if it wasn't an emergency (very pregnant wife / no reliable plumber available for weeks)

Tommy

[Tommy Gilchrist]

W/C soil pipes are 110mm I believe? Can you get a drill bit this size or do you drill lots of smaller holes?

Thanks

tommy

[chris French]

In message , Tommy Gilchrist writes

You can get large core drills - basically like a hole saw for walls for this sort of thing - but you won't do it with your B&D.

[Kalico]

No worries about experience - we all started somewhere and I learn something every single day. Often of not much value though.

From the bath plug hole, use a proper thing called a 'bath trap'. This has a low profile so that the pipe that runs from it can be kept above floor-board level.

Of course, this can then be dropped below floor level and run along the floor/ceiling void if that is possible. Depends on the direction of your joists/boards. DO NOT cut joist to run the waste from the bath though. If they are not in-line to the direction you want to go then run above floor.

Hope that helps. Rob

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[Lurch]

On Thu, 26 Aug 2004 18:34:16 +0100, Tommy Gilchrist strung together this:

Yes, if you're hiring one then the hire centre will be able to sort you out with one of the correct size. Just tell them you want a diamond core drill for a 110mm soil pipe.

[Tommy Gilchrist]

Indeed it does. Thanks to all for the info.

tommy