big ol' pipe

[theflyingpig]

oops! ..

thanks Jason - is there a set ditance from the floor to drill the hole? I was going to go about halfway between the bottom of the trap and the floor - the hole needs to be about 750 mm to the side of where the sink is and then travel a further 400 odd once outside to reach the drain . .

ta

 

[Softus]

Eh?

 

[theflyingpig]

picture a kitchen sink. now picture an outside drain on the otherside off the wall but its about a metre away from the sink, on the right as you look at the sink. my pipe will have to 'travel' from the sink to this drain, going through the hold I am going to drill.

I was planning on the pipe 'travelling' about half the vertical and half the horizontal distance on the inside of the wall, going through the new hole, and then travelling the remaining distance once outside.

this will be the first time I have:

a. used a core drill
b. re routed a kitchen sink waste

thanks for advice

 

[Bahco]

Is there a set ditance from the floor to drill the hole?

You will need to gauge the hole so that it runs parallel to its perpendicular angle to achieve the correct distance both laterally and longly.

Measure the central point first and then the outside diameter.

Post back if you need any more help.

 

[theflyingpig]

sorry Bahco, I don't understand - do you mean the angle on the hole itself?

 

[Softus]

my pipe will have to 'travel' from the sink to this drain, going through the hold I am going to drill.

In that case, install the sink first, then get as assistant to hold a length of pipe at the correct height and 'gradient' while you mark the wall for where you want to drill. Remove pipe and assistant, and drill the hole. Clear the core regularly.

 

[theflyingpig]

softus - its the height and gradient I'm wondering about!

 

[Softus]

The position on the wall will be determined by both:

a) The height of the trap outlet from the sink;
b) The gradient of the pipe.

If you don't install the sink first you're making a rod for own back by having to forecast/calculate a number of parameters, which is why I recommend installing the sink first.

The pipe size should be 40mm or greater, and the gradient should be between 1.8% and 9%, i.e. over one metre distance should be a drop of between 18mm to 90mm.

If you really want to drill the hole first, then work out the trap outlet and use the maximum of the range for the drop, then go lower by another 50mm - you can always use bends etc. to lower the sink outlet end, but if you drill too high (like most builders seem to do) then you'll be b*ggered up a creek without a paddle.

 

[theflyingpig]

softus - many thanks - I will be drilling the hole before putting the sink in - sounds like I've plenty of drop available as the outside drain hole is at ground level and the sink trap outlet I guess (I'm at work so can't measure) at least 500 mm off the floor.

do I have to slope the hole, or will the head be sufficient to push the water out?

ta

 

[Softus]

Well, it won't much matter if the pipe is going to be turning down on the outside, so I wouldn't put any effort into making the hole slope - it's hard enough keeping it level and straight sometimes, what with having to contend with hard bits of brick, mortar, and the occasional wall tie.