Chasing out Wall

[Ian]

Hopefully someone can give me some advice.......

I need to get a waste pipe past a dish washer. The only way I can get the pipe past the washer and have the washer far enough back to sit flush with the units is the chase the wall out and sink part of the pipe partly into the wall.

The wall is constructed of grey bricks approx. 22x7 cm. (Don't know the depth). Can anyway advice me if this is a bad idea and if not how deep I should chase the wall out without *any* risk.

The washer has a recess at the bottom for running pipes but this is actually

10cm lower than the inlet into the main waster pipe in the flats!, so unless anyone knows how to make water run upwards is chasing the wall out my only option.

Thanks in advance.

[Dave Plowman (News)]

It's the head that matters - so dropping the pipe and then bringing it back up again - although not ideal - will still work ok for a washing machine. (think about a u-bend - this is exactly the same principle)

[Ian]

Thanks for your reply......

sink \/\ | | ____________main outlet. |_____________| 1m run

So this will work ?, there will be enough natural preasure to keep the flow running?

I guess that the only problem will be food waste etc. getting stuck at the "up" point. It's a 40mm pipe BTW.

If I can recess the pipe though I assume this would be better?

Thanks agian......

[BigWallop]

Can you raise the pipework to the top of the washer and drop it down the other side. Is there enough room for the 40 mm pipe to run behind the washer nearer the top of it, say, just under its lid.

To tell you it's OK to start cutting chunks out of your walls, when we don't know exactly what they are made of, or how they are constructed, would be a silly thing to do on our part. You say the wall is grey coloured bricks, but what type of grey coloured bricks are they. Are they thermal blocks, which are much larger and softer than normal red clay bricks.

[Dave Plowman (News)]

Right. It escaped me it was a sink waste. Have you got easy access to either end of the lowest part? You could fit rodding ends - these have screw fitting end caps.

It would, but cutting such a chunk out of a wall may not be a good idea. Might be that merely removing the plaster (if there is any) behind the pipe, and not using any brackets so the pipe sits flush against the wall might give just enough clearance.

[Ian]

hmmm.... not really any room above because it sits under a kitchen worktop.

I'm just trying to get an idea about whether or not it's feasible to recess the wall about 20-30mm.... the bricks are standard house size bricks, grey with a smooth exterior. They seem pretty dense.

The wall is a partition wall between two flats built in the late sixties. Bricks have been layed end to end in one row then the next row is side by side (so the end of the brick is visible) autonated up the wall.

Do you think I'm wasting my time with this option or is it worth getting a builder to give me a quote ?

Thanks.

[Ian]

Thank you all for your help.

I've measure it all up again and I think that, if like you say, I take the plaster off the wall, sit the pipe right against the wall I should be OK. I found that the worktop I'm installing is 616mm deep rather than 600mm, this, aswell as removing the plaster has bought me enough space.

If I need to grab an extra 5-10mm I will make a *small* recess in the wall. I checked exposed brick work and the wall is a 9" partition wall so nicking

10mm shouldn't be a problem (According to a build mate anyway!). There is actually a pipe already recessed in this way.

Cheers, Ian.

[Set Square]

Er . . in that case it *would* have to run uphill from the sink outlet, with nothing to drive it!

[logized]

You need to refer to Building regulations document A (downloadable from the government website )

extract is here -

2C30 Chases:

a. vertical chases should not be deeper

than 1/3 of the wall thickness or, in cavity

walls, 1/3 of the thickness of the leaf.

b. horizontal chases should not be deeper

than 1/6 of the thickness of the leaf of the wall.

c. chases should not be so positioned as to

impair the stability of the wall, particularly

where hollow blocks are used.

Dave

[Ian]

I should be OK then, cheers.

> an extract is here -