Macerator being installed in new open plan kitchen

[joneech]

Hello there,

I'm looking for a bit of advice. We're in the middle of renovating our new top floor tenement flat and we've created an open kitchen to living room in what was a cupboard and recess. We will only have the sink requiring drainage as the washing machine has been left in position elsewhere in the flat, and our architect has included '50mm upvc taken under floor and connected into existing drainage'. Our builder hasn't followed this instruction and has instead installed one pipe running up the wall which will be connected to a macerator and then into the drainage.

Does anyone have experience with this sort of thing? Our builder has told us that due to the floorboards and joists, we can't run the pipes under the floor (this would notch joists) and he thought we wouldn't like the pipes running along the skirting boards of the new room.

Any advice/help would be greatly appreciated!

Thanks,

n

 

[denso13]

Use a macerator only if there are absolutely no other options. Avoid them if at all possible.

 

[muggles]

Don't put a macerator in. Ever.

 

[SimonH2]

it won't be a macerator (they are for the bog), but just a pump.

Put simply, it'll work but is best avoided. It's something to fail, and when it does then it'll overflow and wet your floor (unless someone noticed that it's not running). In theory, the Sanivite pumps have a flap that lifts and blocks the vent when this happens, but when I tested the one I put in the garage of the flat, it leaked elsewhere once full

The builder is (probably) talking out of his derriere regarding running the pipe. It is possible (and preferable) to drill holes at the centreline of the joist and feed the pipe in - but if retrofitting then it's quite difficult unless you have access to feed the pipes in from somewhere without having to go round corners.
If the "existing drainage" is an outside stack then the pipe will have to go through the wall. That means he could drill through the wall, drill the joists, and feed the pipe in from outside - still fiddly but completely doable (probably - it depends on the layout).

It is important to note that there are rules as to where, and how big, you can drill holes in the joists. 50m is quite big, and you may find a 40mm or even 32mm pipe may be the limit for the joists - though that would slow the sink draining.
I've seen some horrendous hacks (literally) where people have taken out huge chunks from a joist and severely weakened it. On one occasion, someone had gone a full 1/2 way down to get two pipes in one above the other

Whatever the situation, the builder should have mentioned the issue before changing things.
EDIT: And of course, the architect shouldn't have specified something that's not possible (if that is how it turns out).

 

[tincup]

Hi

One of the pro's working for you is wrong. How far is the run?
what is the width and depth of the joists?

 

[joneech]

Thank you so much for your helpful replies! I have no idea how people figure this stuff out with their first property...it's mental!

Managed to convince my builder to check under the floorboards and turns out it was fairly straightforward to sort out under floor plumbing without affecting any joists! He hadn't checked initially and made assumptions based on his experience. So we now have proper drainage without the need for a pump phew!

Thanks again,

n

 

[SimonH2]

Thank you so much for your helpful replies! I have no idea how people figure this stuff out with their first property...it's mental!

Sensible ones get second opinions, others just accept the first their "professional" tells them. Lucky ones have a family member (or friend) who knows enough about such stuff to ask the right questions.

Managed to convince my builder to ...

Did he wear spurs and a stetson ?