Shower waste with concrete floor

I am finalising the details of the a bathroom refurb which includes a 1000x900 shower enclosure. The shower will be located against two internal walls and the floor is a concrete slab. I understand the usual way around this is to raise the shower tray using a purpose built kit or d-i-y frame and surface run the pipework - not the best result from a looks viewpoint.
The only alternative would seem to be digging an 90mm deep x 3 metres long channel in the floor to meet up with the existing bath waste. A bit of googling reveals that this is frowned on by many as it may have maintenance implications. Given that shower wastes are now accessible from above which should cope with any likely blockages is there any reason not to consider this alternative?
Grateful for your thoughts. -- rbel
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rbel wrote:

You can have the pipes boxed in - I've used 175mm upvc coverboard for this in modern bathrooms including my own. Boxing in used to always be done in plywood / hardboard etc and it always looked crap, but I would consider this long before I contemplated digging up a concrete floor.
Where do the water pipes enter the shower cubicle?
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On Mon, 16 Jul 2012 20:08:40 +0100, "Phil L"

Boxing in is a last resort - there is also a lot of resistance to raising the shower tray and forming a step up from floor level at the entrance to the shower.
The H&C supply are routed via an adjoining coats cupboard, which unfortunately has no access to drainage.
-- rbel
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rbel wrote:

If you must go through the concrete, use one continuous length from shower to outside, don't have any joints buried in the concrete, also, don't forget it will have to be sloped downwards towards the exterior wall otherwise you will end up with an inaccessable clog of body fat and hair. The channel will therefore have to be deeper at the wall furthest from the shower. The pipe will be carrying both hot and cold water and will be subject to expansion and contraction, so best bet will be to wrap in fibreglass prior to cementing and tiling over to allow movement without cracking tiles
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On Mon, 16 Jul 2012 20:50:02 +0100, "Phil L"

A 3 metres length of 40mm pipe will span the distance between the shower waste connection and the exterior drain or the bath waste so no joins until then. I understand that the minimum fall should be 54mm for 3 metres.
I had thought of leaving the waste pipe uncovered in the floor slab channel where it runs under the shower tray and length of the bath and just covering it in a 500mm area between the shower and the bath, which can be insulated as you suggest.
-- rbel
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On Mon, 16 Jul 2012 19:02:32 +0100, rbel wrote:

You'll need some drop, obviously, so the way that I'd minimise it is to fit a 32mm bend (should be plenty big enough unless you're using a super-power shower) and the HepVo trap in the straight run: http://www.a-s-m.com/hepvosanitarywastevalve.html
--
Peter.
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Phil, Mike and Peter, many thanks for your comments.
-- rbel
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