Sewage smell outside house near new toilet

[MeaMaximaCulpa]

Last year, I had a garage converted and included a new toilet room in the development.

I noticed when it was all put in, that outside the house, near the new waste pipe and soil stack, there was an intermittent sewage smell. My builders played it down and so I though it would be temporary.

About 8 months on, we're noticing an increasingly overpowering smell of sewage round the side of the house, outside, where the waste pipe and soil stack are situated. We can't open windows on this side of the house anymore and gag when we're in that area outside.

Not sure if it's a smell from the waste pipe or the soil stack. The soil stack doesn't end very high up because it's right beside a flat roof area outside my son's bedroom. I again had queried this with the builders but they said it had to be there as it needs to be directly vertical above the waste pipe.

If the smell is from the soil stack, not sure it could be extended a lot lot higher, so it ended way above the flat roof and my son's bedroom window - as this would end up as a really tall soil stack that could potentially blow down in high winds. It would also then be visible from my son's bedroom and presumably lower the potential sale value of the house.

Can anyone give me some advice about all this? Builders aren't responding to my contact though were out here about a month ago, discussing another problem - but haven't got back to me about further works at all.

So would this sewage smell likely be from a soil stack or from a waste pipe? I've sniffed around the waste pipe area and there's no noticeable intensifying of the smell and it's much more noticeable when it's windy. So I'm worried it's probably from the short soil stack. Any ideas?

Oh no! Just been researching on the web and if the problem is the sewage gas from the soil vent pipe, outside my son's bedroom - then this might explain why he's had a persistent dry cough all summer - when the windows have been open a lot.

Looks like this gas can be a major health hazard and even lead to explosions cos of the methane.

How can I find out whether the sewage smell is definitely coming from the vent pipe? PigletJohn - have you any advice or suggestions please? Really worried now.

There re building regulation rules with how high the soil stack has to be above windows, etc. sounds like yours may be too low.

You can also grease any manhole covers to make them more airtight and this stops smells coming through from covers.

Building regulations vary by jurisdiction, of course, but in this part of the world a vent pipe must be a minimum of 12" above the roof, and 2' above and 10' away from any opening window.

Look at the photo attached... notice how the pipe extends above the roof. Notice also the supporting strap near the top of vent pipe. www.flickr.com/photos/dalesd/2691314530/sizes/l/

Look into the manholes.

What size is this "waste pipe" you mention?

How do you know they connected the WC to a foul drain and not to a rainwater soak-away? When you submitted plans for Building Regulations approval, what drains did they show?

Stop using that WC.

Ask around for an experienced local plumber. He might not want to dig up the drains but will probably spot the fault easily.

Thanks. Not sure of size of waste pipe but I think it's standard. I watched them dig up a patio and drive area and lay a new waste pipe to connect it to the foul drain pipe already there and I assume that this is what they did but can't be certain they didn't mistake it for the rainwater soakaway. To check this, the entire patio and new steps and driveway would need to be dug up again!

The plans from the design/architect person seemed to show that the pipe fitted would and should connect to the foul drain.

CanadianJohn, there are brackets on the soil vent pipe but it ends at the base of a flat roof area which must be about 8 to 10 feet higher than the flat roof. The flat roof is adjacent to my son's bedroom window and the vent pipe would obscure the view from that window and sort of 'hang there' in the air, not right adjacent to the house wall, which stops in that flat roof area.

You couldn't therefore get a support strap/bracket for the last 8 to 10 feet of the pipe, if it were extended, as that length of it would not be adjacent to a house wall.

The builders already kind of ruined that view by siting the extractor fan vent pipe within the middle of that flat roof.

So the resultant soil vent pipe is a few inches only below the flat roof level - thus BELOW the height of the opening bedroom window and only about 8 feet from ground level.

No smell this morning as no wind blowing. Frustrating as I can't exactly time a visit from a plumber to coincide with when the smell is there but when it IS there, it's very strong.

Do you mean the waste pipe is 100mm?

I've now had a good look. The pipe says on it: 110mm x 87.5 degrees CENTER OSJ92 - on the lower part. It's greay PVC.

Higher up the vent pipe - also grey PVC, it says: F14500 3m Soil pipe CSPS3 CENTER. However, it's possibly less than 3m high - more like 8 to 10ft - not sure of the conversion to metres.

The lowest part - that's cemented in and goes right into the ground - is a pale 'terracotta' coloured PVC pipe that is pushed into the grey pipe and has no numbers or letters visible on it.

I've sniffed around the lower areas - at ground level - and can detect no apparent smell at all. Will have to get stepladders and sniff right near top of soil vent pipe but suspect that this is where the smell is coming from and that when it's windy, the smell is blowing down wards, as there is a garden shed wall about 3 feet from the house wall here. So a kind of 'trap' area for air to collect, may be created.

Many thanks PigletJohn.

Does any of this help?

that sounds like correct soilpipe. So you haven't got a saniflow

The one market 3m was sold in a 3m length before being cut to size on site.

If there is a horizontal run, and no bath or shower running down it, sometimes there is insufficient water flow to wash the solids along.

I still think an experienced plumber should roll his eye over it.

Have you looked down the manhole covers?

"a pale 'terracotta' coloured PVC pipe "

the brick-coloured plastic is usually used underground, and grey above.

the soil pipe should go into the collar or socket of the fitting. Sometimes a loose collar is used, and the brown pipe and the grey pipe both go into it, which is OK and nearly as good. Such a collar has a bulge running round it where the upper and the lower "rubber" sealing rings are. The collar which is moulded onto a fitting only has an upper ring.

You can perhaps see this has two sealing rings but this has only one.

Erm, just to hijack a minute - PJ I have a horizontal run of soil pipe under the house and the shower attached to it is only run a couple of times a week. We now have drain flies in the downstairs loo and I wondered if that might be related? Can I pour something hardcore down the loo/waste to clean them out?

I wouldn't have thought it was connected.

If you have a dual-flush WC, use the full flush more often.

p.s.

I haven't seen drain flies. Might there be a leak? If you put food dye in the cistern, see if the colour shows up anywhere. It might be leaking under the floor, which will be harder to see (and to repair)

also, if it is badly designed, the suction from the waste might be pulling the water out of the shower trap (they are supposed to be deep enough to prevent that happening).

Put a pint of water, with half a squeeze of WUL, down the shower trap twice a day and see if the flies stop.

Look for the instructions for cleaning hair out of the shower trap, and look down it to see if it is full of water, as it should be, even when you have not poured water down it.

Oooh - maybe it's the lodger's long hair! She uses that shower occasionally. I shall get cleaning. I'll also poke at the connection between the loo and the waste pipe, it looks a bit grim (builders did that one, not me). I have a spare connector so could always replace if the seal is shot.

Drain flies are rank by the way - like super powered fruit flies. Bleurgh.

'mmmmm

saw this

OP again, PigletJohn. The smell is definitely coming from the top of the soil vent pipe and not the base near the drains. Have been up on a ladder today clearing gutters and right beside it and it's horrible!

I presume it should be much much taller in height, away from the ground level but as I said in previous posts, this would be tricky as it'd effectively extend up into air space as the house wall stops at the flat roof and when it continues, this is a few feet in from the flat roof. So for the pipe to extend to house roof height, it'd have metres of unbracketed pipe.

Would that work or would it blow down, as I fear?

Also, it'd be an eyesore outside my son's bedroom window.

Finally, am I right in assuming now that the smell will be 'ordinary' smell from the top of such a pipe but that we don't usually smell these as they're normally situated well above head height at roof level? Or - even with a short pipe, should no smell be apparent and would that then be indicative of an issue with the sewage system?

Can't lift the manholes at present and can't stop that toilet being used as this is my business office and business clients use it maybe 3 times a week. However, this toilet has therefore v v little regular use.

There's also a shower room that I assume uses the same waste system. This is for family use but has actually only been used 3 times in the last 8 months since the shower was installed. Have read something on the internet about needing to have regular water flow through these systems in order to flush away sewage and make the vent system work or something?

Might it be that I should be turning on taps and shower more regularly and flushing that toilet regularly and could the lack of use be the source of the smell ourside? (No smell inside by the way).

That toilet has been used I think 3 times only for 'solid waste' but to put it bluntly, could each of those have got 'stuck' somehow and this be what's smelling above the vent pipe or would we smell sewage anyway around the top of a soil vent pipe if they were all situatted as low to the ground as this one?

How about a roof brace kit to support the soil pipe... here is one, adjusts up to 10' long - for a chimney, but I'm sure there are similar things for soil pipes.

www.ventingpipe.com/metalbest-urbk-class-a-chimney-pipe-universal-roof-brace-kit/p1070018

the soilpipe vent should not routinely smell bad.

I won't be surprised if when you lift the lids and look in the chambers you find an accumulation or blockage. If not, leave the lids up while someone flushes each WC and pulls the plug out of each bath and basin in turn, look for a good clean flow.

Back again. I'm really worried that the methane gas is a risk - ie explosive and also a health risk to my son particularly - who sleeps in the bedroom beside the vent pipe and who has his window open all day and night. Should I be concerned or am I over-reacting?

Have now done lots of research on the web and I've also hopefully got a plumber coming out sometime next week to have a look.

I think the problem maybe to do with the 'plumbing traps' that may have gone dry or lost enough water that the water seals inside the trap has broken - so the sewage smell is rising up through the vent pipe. Is this something about the P-trap being emptied by a vacuum in the waste line?

I'm speculating this to be the case, as when the toilet is flushed (which is infrequent, as it's the least used toilet) not very much water flushes through it and the toilet bowl level is fairly low. But I may be completely wrong to deduce there's an issue with the plumbing traps. I'm just going by what I've learned from the internet.

I doubt the issue is a clogged vent pipe as there are no trees etc near the vent pipe entrance and it's so newly installed.

It might be blocked waste pipe but I doubt it, as this toilet has barely been used at all in the last 8 months since it was installed. So I'm inclined to think it's to do with something about the P traps going dry.

I also think it may be because the vent pipe ends BELOW the bedroom window and well below the main roofline. This would mean that any issue at all with the vent pipe /vacuum/ P trap will be even more apparent as it's so near to ground level.

Wish I'd trained as a plumber! The plumber who fit this new toilet made such a hash of it that it leaked 4 to 5 times and had to be re-installed several times - in the end by a different plumber. But at last it stopped leaking. However, looks like he may have done a botched job in the rest of the system.

I'm really hoping that I won't need the walls taken down and the waste pipe dug up outside (a massive job).

Finally, it's not a year yet since the works were done. Do I have any right to claim against the original builder or is it difficult to prove fault with his plumber and has too much time passed since works were completed?

plumbing traps can dry out, but unless there is a defective design causing then to syphon out, it takes more than a couple of weeks.

Basin, sink and shower traps can easily refilled with a pint of water or less. A WC you can just flush and it will leave the trap full. A full trap will not allow sewer gas to enter the house (unless perhaps there is a blockage or design fault).

Saniflows can sometimes have undesirable effects but you have not mentioned one.

It might be tiresome trying to claim against a builder. Your claim will be whoever you paid, even if he used a subcontractor. You would probably need some kind of expert witness to say design or build not done to a satisfactory standard.

Building inspectors have the authority to look at drains before they are backfilled and covered up, but will deny any responsibility if they failed to spot a defect, or were busy elsewhere and didn't come.

PigletJohn - just had plumber out and it's NOT good news. He's sure that the waste pipe system has been incorrectly fitted. It doesn't slope downwards but upwards. The inspection hatch, which we lifted, shows sluggish movement, a past block/overflow and a construction that is a right angle bend to the next pipe, thus encouraging blockage, especially as there are plastic parts of it that will cause waste to stick onto it inside.

Disaster! This is causing all the smell - not the siting of the soil vent pipe. Lack of use of the toilet won't be helping but in any case, every use will accumulate more blockage.

He says I need a drains company (not rip-off ones though) to come out and flush the system first. But he warned me that if the pipes are a botched job, the water pressure could lead to cracks and sewage leaks!

He also said the problem would recur as the system is laid wrong. I'll need all the new waste pipes dug up - which will mean removal again of a new patio area, steps, the entire driveway - and then all put back again too. While works are going on - which will be expensive - I'll also suffer loss of earnings, as I work from home and business clients use the office and toilet.

So - if i can't claim this from the original builders, I'm out of pocket and can't even really afford the works done anyway. If I can claim it and the builders re-do it, they may botch the job again - but even if they don't I can't work, whilst the job's being carried out. This is really bad news for me.

Two people run the building company. One of them and his father did the drainage works. No way will they want to admit they did it wrong. How can I prove otherwise? The plumber today has said, understandably, that he doesn't want to get involved in any dispute. Where do i go from here?

grrrrr

don't know

See if your home insurance includes legal expenses cover.

i.e.

this sounds like a substantial amount of money, so I think you should be taking legal advice, even if an amicable agreement is subsequently reached.

You are supposed to give a builder the opportunity to correct faulty work, but I would be reluctant to let builders, who ran drains that tried to make water and sewage flow uphill, back in my house.

Call the office of fair trading and see what they suggest. They have loads of advice online re: bodge bldg work. Definitely get advice!! Sounds so stressful :(