Runnung bathroom waste under floor, through joists.

What the contractor said is correct.

If you want to put the waste in the ceiling void, you will need to arrange the layout to run the waste parallel to the joist.

Depends.

What size are the joists? How long are they? Where would the holes be in relation to the ends of them?

"Correct" is an over simplification... It *might* be correct - but we can't tell from the information given.

For holes drilled through the joists, the hole must be at least 0.4 x joist span from the end of the joist, and the hole can be no lager than

So say you had a 2m joist, and it is 200mm tall, then you can drill a hole up to 50mm as long as it is 800mm from the ends.

Notches can be nearer the end but not at the very end. So 0.07 x span to

Depending on the above - possibly.

Running waist above the floor, adjacent to the wall, and then boxing in with skirting on the front is another option, or running a pipe out through the wall and routing it externally is another.

Along the lay of the joists. Or by strengthening the floor

Could a joist be reinforced with a metal plates or plywood in order to accomodate a larger hole?

Of course.

There are many ways to solve that problem, none of which are known to

Typo - that should be 100mm apart

-- Cheers,

John.

/=================================================================\ | Internode Ltd -

There's a typo with lager, too. Maybe too much? :)

That may mean a step up into the shower, though.

The bathroom is roughly square.

The wall with the current WHB backs onto the landing. The waste currently runs under the bath.

The bath takes the full available length of the side away from the door opening.

The outside wall is mainly window, past the end of the bath.

The side wall on the door side has a towel radiator.

I would have to lift a floor board to measure the joist depth and spacing.

Our requirement for the shower tray replacing the bath is no upstand, and preferably low profile. This is to cover the expected future requirement to be able to shuffle in and out of the shower. Certainly not a 100mm upstand plus the depth of the shower tray (minimum

One alternative would be to move the WHB to where the radiator is, and move the radiator to the internal wall where the WHB currently is. Allowing the waste to run above the floor to the soil pipe in the corner.

This might work - need to consult.

I will lift a floor board and check dimensions and direction.

Cheers

Dave R

Have you considered dropping the pipe through to the room underneath and running it boxed in under the ceiling. In our last house I had a similar problem doing the above was the only solution. In the end it looked OK as to the left in the room below the bathroom there was a pillar part of a wall that had been removed and to the right some pipe boxing so the boxing in below the ceiling formed an archway.

Alternatively if it is not too big a job a complete false ceiling might look pleasanter

The joist sizes and directions are going to be deciding factors.

In many cases plumbers will simply notch the top of the joist rather than drilling through it on the centre line.

This is a fairly common approach particularly if they need to run the waste across a number of joists, simply because it is nigh impossible to thread a length of rigid pipe through holes drilled in the centre of a number of joists.

I can't remember the exact figure but the notch can't be more than something like 15% of the joist depth. A visit to the planning office of your local council would be worthwhile to confirm what is permissible.

The suggestion that the waste be run vertically down (assuming your property is a house rather than a bungalow) has some merit as it would permit the installation of the shower tray with no upstand. The only negative is if you need to gain access to the trap should it become blocked and chemical/mechanical means can't unblock it.

FWIW (probably not a great deal!) I was tasked with trying to route wastes under the floor of my bathroom to fit the existing.

I decided it was all too much trouble, and involved some convoluted routes and quite a lot of joist hacking.

In the end I moved the basin and bath (toilet stayed where it was) round to meet the outside drain more neatly (so, on an outside wall) - replaced over 6m of pipe with less than 1m, and everything except the water supply is above the floor, the whole lot concealed by the bath and basin cabinet.

It's not a very good pic but:

It's probably better to move things around BUT, if you're stuck, a shower waste pump is not very expensive and would allow you to have a walk-in shower and run the waste at floor level.

I noticed that as well - but figured lager was less likely to have you drill holes to close together, so CBA to mention it :-)

If you are drilling through joists, how do you get teh large waste pipe through? They're not that flexible.

In my case simply unavoidable ]

But the waste the runs behind an enclose bath to and enclosed downpipe from the loo...

Thinking back, the washbasin is ion the other side of the room and I have memory of where its waste goes apart from into the wall..as there are doorways between it and the main wast downpipe.

Of course for a shower you can uses one of those electric shitpumps to pump the waste out

In message snipped-for-privacy@mid.individual.net>, No mail snipped-for-privacy@aolbin.com writes

snip Point of order on walk in showers..

I fitted one in a ground floor *toilet/shower* in anticipation of possible future disablement and wheelchair use. Despite an air inlet valve on a stubby stack, the shower trap can suck dry with bulky toilet waste; allowing drain smells into the room:-(

Chop into shorter sections, insert and then solvent-weld them back together ...