Shower waste pipe and concrete floor

Stu2010 · 7 Oct 2010

Hi All

I'm replacing a bath with fitting a new shower cubical. Sadly, I have a concrete floor... I was wondering, would i be ok to cut a channel in the concrete floor and sink the pipe.

Its 40mm pipe and would need to run about 1.5m to the external wall.. so i'm guessing i'd have to dig a channel that goes from 40mm deep to about 70mm deep..

Am i going to run into major structural problems with the concrete floor if i cut the channel

thanks

Stu

plumb111 · 7 Oct 2010

Hi
Can the shower tray not sit on a wooden plinth, or by a tray with legs.

Rgds
Peter

Stu2010 · 7 Oct 2010

Hi

I would really like to avoid building a wooden plinth or elevating the shower tray i have a very eldely aunt who finds steps very difficult, hence why i want to sit the shower tray on the floor and dig out the channel for the waste pipe.

Thanks

Stu

londonboy · 7 Oct 2010

You could use a whale pump and then you would only have to channel in a 15mm pipe.

muggles · 7 Oct 2010

You can channel out the floor, normal waste fall is 40mm/metre. Make sure you don't compromise the damp-proof membrane, and if you do make sure you seal it up again.

BournemouthPlumber · 7 Oct 2010

and watch out for any pipework already buried in the floor!!

Stu2010 · 7 Oct 2010

Thanks for the advice guys

Two more stupid questions...

1) The house was built in the mid 1970's... how will i know if i've gone through the DMP? is it a physical DMP that i'll be able to See

2) Can you please explain what whale plumb is and where i can get it? i like the sound of only having to dig out 15mm instead of 40mm

thanks for all you help guys

Stu

muggles · 7 Oct 2010

The DPM is just that, a membrane. It's plastic sheeting basically, so yes you'll see it. There's a chance you won't have one, depends how good the builder was, things were sometimes a bit lax back then.

No idea on the whale pump I'm afraid, never come across one myself, LB will have to help you there

ChrisR · 7 Oct 2010

CHances are you'll have a low-strength "screed" over something harder.Position of the dpm is highly variable. If you HAVE to penetrate it you can fill all round with waterproof stuff - various techniques, check the builders' forum.
You MUST have a fall though, showers are bad for sludging up, and you need to find whewre your drain outside is going to be.

It might sound horrendous but digging up a lot of floor and installing a wet-room floor, is mostly just simple slog and gives a result you won't regret doing. No edges, no worry about water in the wrong place, ultimately no need for a cubicle, fine for wheelchairs even. You can either tile(slippery?) or use a pro vinyl floor with raised skirtings.

electronicsuk · 8 Oct 2010

I'm surprised nobody has mention this, but can we confirm that this is a downstairs floor? If it's upstairs then the concrete will be structural and you must not chase it.

ChrisR · 8 Oct 2010

Fair one, yes, I assumed

. SHould know better!

htgeng · 8 Oct 2010

ChrisR said:
Fair one, yes, I assumed . SHould know better!

I can see the headlines now 'Maisonette collapses. Man says "I was just fitting a shower for my aunt and the floor just fell away. I can't explain it!"

londonboy · 8 Oct 2010

http://www.whalepumps.com/drainage_solutions/premium_wet_rooms/dry_deck_case_studies/

They only need a 15mm chase in the floor.
Be aware they do make a gurgling sound

Stu2010 · 8 Oct 2010

Hi Guys

Thanks so much for the advise.. Its very kind of you. Yes.. It is a down stairs bathroom but thanks for the tip about not chasing out any concrete floors in upstares rooms.

I think a wet room would have been the answer.. sadly my aunt bought all the stuff before i got involved.. so I'm just trying to make the best of what she's bought..

One last question.. if you don't mind.. My aunt has bought cork laimnate flooring. Its the stuff that clicks togeather. ( apparently suitable for bathrooms) The problem i have is that the laying instructions tate there must be a 10mm expation gap around all the edges.. This fine for most of the room.. but i'm not sure what to do about around the shower tray as the shower tray is curved and needs to be laid on a bed of sand and cement..

Could i lay the whole floor in the laminate, then and and cement on top of this and then lay the shower tray??

what would you rcomend..

Thanks again

Stu

Threadjacker · 9 Oct 2010

Hi Stu

NO!

Never attempt to fit the tray onto springy laminate, the tray needs to be on section of 18mm WBP plywood with a weak sand cement mix, use a good quality silicone and appy a generous amount to the edges and squash the tray against the wall letting the silicone ooze out.

Tile down onto it leaving a 2mm gap and run the secondry silicone seal after grouting.
I would leave your 10mm gap round the edges of the room and use the beading, but round the tray I would cut in within 2 or 3mm and run a nice bead of silicone round it.

I0mm gap around the tray would just look like you've cut it short.

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Shower waste pipe and concrete floor

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