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Posted: Mon Sep 06, 2004 4:37 pm
by disaster_jack
Hi,

I had a bath and WC along side each other in the bathroom. I want to replace bath with Shower tray and move the WC.

Groundfloor - solid floor. If I move the WC I am thinking I could have the waste pipe going straight out throught the wall (rather than digging up the floor in the bathroom and trying to drill a new hole through the "house wall" below ground level).

Presently there is an inspection chamber right out side the bathroom window. Going upstream (in the IC) is a 100mm pipe which goes to a SVP about four feet away. This is about 8 inches away from where the new WC pipe will come through the wall.

Can I connect the WC outflow directly to the SVP, presumably leaving the SVP above this join as it is now?

Having removed the SVP for inspection I have found that below ground level (about 3 - 4 inches) there is a 100 mm pipe elbow, at 'this' end it has an internal diameter of about 110mm, the SVP has a diameter of 110mm also. Above this elbow there is a final covering of concrete about 3-4 inches thick, and at this point above the elbow there is a pipe slot which the SVP went into, this is misalligned (off centre) with the elbow by about 8mm. Presumably I will have to allign the SVP properly with the elbow? I believe it is misalligned because the brackets holding the SVP to the wall hold the SVP off the wall by a specific unadjustable distance, and unfortunatlely this was 8mm away from the elbow below ground.

Assuming you tell me I have to allign the elbow with the SVP properly, how do I then fix the SVP to the wall?

On a more general note, what could the consequences be of removing the SVP (unsightly) altogether? If their function is to allow air to enter and leave the drain system, would this air not just go in and out around the IC covers? I suppose the arguement could be that the IC covers could become sealed with dirt, but I don't see it as being a particularly serious problem not to have an SVP.

Next, is what to do with the shower waste. I will have to dig up the solid floor in the bathroom, and I am thinking the 40mm waste pipe will go through what is the existing WC pipe - through the 'house wall' (below ground level).

My research has led me to believe I will need a "P trap" with a seal depth of 75mm. As the 40mm waste pipe will go directly into the IC through the existing WC pipe. Does this set up sound ok to you? where can I get a P trap with a 75 mm seal depth? the ones I have seen so far (including the one I took off the bath) only have a seal depth of about 8mm - 10mm. Would it matter if when lifting the IC cover you could see the 40mm pipe protruding from the house? How could I do it better?

Posted: Mon Sep 06, 2004 9:28 pm
by 84-1089053830
Can I connect the WC outflow directly to the SVP, presumably leaving the SVP above this join as it is now?


I can't see why not - assuming I've understood the layout correctly.

The 'elbow' you meantion is more correctly known as a "rest bend" or "long radius bend". The SVP, which is the vertical pipe leading up into daylight from the rest bend should be directly aligned - this is normally achieved by use of a coupling, so I'm not sure how your's has come to be misaligned.

Once you've got the SVP properly aligned, you can use one of the adjustable wall-fixing brackets to anchor it fiirmly in position. Any decent BM should be able to sell you these items as they really are everyday stuff.

If you remove the SVP, you need to have some other way of venting the bog, and this may be via an AAV - an air admittance valve. This is where it gets tricky as, without seeing the actual layout, I can't say what would and wouldn't be acceptable or feasible.

Finally, moving on to you shower waste, this falls into the realm of 'internal plumbing' rather than draionage. As a general rule, us groundworkers are not allowed inside the house with our mucky boots, our chunky pipes and our coarse manners - we have to let 'plumbers' do all the internal fittings (plumbers are best thought of as pipelayers who are scared of the rain! :;): ). So, any pipes outside the house and below ground, are proper, manly "drainage", while anything inside the house or above ground, is girly "plumbage".

Anyway, internal plumbing fittings are outside my realm - I have catalogues, and I know what you mean, but I really don't know where to recommend as the most likely source. Whenever owt like this came up, I 'phoned my mate Keith the Plumber and he got hold of whatever was needed from some hidey-hole near Bolton that plumbers are wont to frequent. Have you tried a local Plumb Center (sic)?