read with interest the above project, and am wondering if i could use this to help with my gurgling bath trap?
When i pull the plug on the hand basin, i get terrible gurgling from the bath trap and have on a few occasions had water come back up thru the bath plughole.
The sink drains away quickly enough, the bath takes somewhat longer. I am sure there is no blockage, as i have recently dis-assembled the bath trap, cleaned it out, and removed the sink. I fed a pipe cleaner thingymujig down from the bath waste, past the point where the sink tees into the pipe and on down to the main waste. The thingymujig came back up clean but to be on the safe side, i also fed a drain attachement down from my pressure washer. I regularly clean the pipes with soda chrystals.
The bath doesn't get much use since i had a wet room installed downstairs but the sink is in constant use and the noise is horrendous!
Dunno if i can add a drawing of the plumbing route to the post but if not i will happily email it to someone if they feel they can help me.
This is typical of what happens if someone combines the bath and basin wastes. The regulations say each should have its own independent pipe.
What you are experiencing is actually the opposite of what is shown in the project. There air is being drawn in to the pipe causing the gurgle. When you pull the basin plug because it is so much higher than the bath the water rushing away is forcing air and even some water out of the bath trap. An AIV only allows air INTO the waste.
The only way to cure the fault is to replace the wastes.
I actually made no changes to the plumbing under the floor, all i have done is to replace the bath and the sink, the actual pipework has been in situ for at least 20 years. I have been in the house for 5 of those. I replaced the bath & sink 2 years ago but this problem has only just raised it's ugly head.
Assuming that as you say, i need to give seperate wastes, this would be major work for me, the only option would be to remove a Tongue & Groove ceiling in the kitchen to gain access.
Would it be possible to run a surface mounted waste pipe and run it into the toilet waste?
If this has just occurred, then the waste is slowly blocking up. It is possible the combined wastes have been ok whilst they are new, but as they naturally clog up, the flow is reduced to the point it becomes a problem.
If you can try and clear it by pushing a hosepipe at full flow as far down the waste as possible. Sometimes this will clear debris sufficiently to cure the problem.
If there is room for a connection in the pipework you can connect the basin at the back of a toilet. I wouldn't make drastic changes to the plumbing without trying to clear the pipes first. If it worked before........
I'm pretty sure that the wastes aren't blocked, certainly not until they reach the main waste pipe. If i remember, the wastes are conected to the soil? pipe, the one that carries the poo etc from the lav. The toilet show no sign of any blockage in deed works beautifully. is it possible that the poo pipe is becoming clogged? i'd have thought though that i'd get a problem with the toilet first rather than at the bath/sink waste because it's closest to the pipe?
I will give the bath waste a good going over with the hose as you suggest though first.
No, as you say, it won't be the main soil pipe that is blocked because that certainly would show up in the toilet worst.
The bath and basin waste pipes don't have to be blocked a great deal to have the effect you are experiencing. Remember, the back flow into the bath will be at best almost happening even if the pipes are new and clear. Over a period of time, limescale and other matter will collect and although may not significantly reduce the pipe bore, is likely to reduce the speed of flow which can cause the problem.
I would certainly agree with you about the limescale issue, we have a major problem with it here in wiltshire. Are you aware of anything that i could use to pour into the waste pipe to alleviate it? tried the stuff you can buy like mr muscle etc but i doubt whether that would help shift 50+ years off accumulated limescale. If you can suggest anything, could you let me know where i am likely to be able to find it and if it would be ok with the plastic fittings.
I have a similar problem that also did not used to be apparent until a couple of years ago, however I' don't agree with some of the suggested ideas for root cause. I live in an area with very soft water and absolutely no scale issue and also the waste pipes are certainly blockage free. My thoughts are that this is a venting issue, i.e. when you discharge water into a drain pipe from a basin or bath, then air requires to be expelled. Shoud the vent pipe have a restriction then a small backpressure will build-up in the waste pipes and if this pressure is larger than the few inches of water head in a waste U bend, then air will bubble through. I havn't verified this yet, it is just a theory, but I need to get onto the roof and ensure that the vent is not restricted.
Try fitting an in line trap to your bath. An in line trap would certainly fix the problem of the gurgling as they dont hold any water in the trap, they use a plastic film that the water can flow through but then closes up after the water to stop the drain smell coming back up.
"Try fitting an in line trap to your bath. An in line trap would certainly fix the problem of the gurgling as they dont hold any water in the trap, they use a plastic film that the water can flow through but then closes up after the water to stop the drain smell coming back up."
Hope he might have solved it by now LoL. The HepVO works only as long as it doesn't get jammed up with soap scum, hair etc. When that happens it stops functioning.
Does anyone know the source of the regulations in the comment from Plumbob in the posts above that "This is typical of what happens if someone combines the bath and basin wastes. The regulations say each should have its own independent pipe."
My sink and bath gurgle and have a common pipe. I would like to be able to discuss this on a sound basis with the builders who installed the work.